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</style><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /></head><body><div xml:lang="en" class="book" lang="en"><div class="titlepage"><div><div><h1 class="title"><a id="idm45490015313024"></a>dracut 12e4c10f8a21272f796afbd6c1408dd41885f6ab</h1></div><div><div class="author"><h3 class="author"><span class="firstname">Harald</span> <span class="surname">Hoyer</span></h3><code class="email"><<a class="email" href="mailto:harald@profian.com">harald@profian.com</a>></code></div></div></div><hr /></div><div class="toc"><p><strong>Table of Contents</strong></p><dl class="toc"><dt><span class="part"><a href="#_introduction">I. Introduction</a></span></dt><dd><dl><dt><span class="chapter"><a href="#_definition">1. Definition</a></span></dt><dt><span class="chapter"><a href="#_rationale">2. Rationale</a></span></dt><dt><span class="chapter"><a href="#_implementation">3. Implementation</a></span></dt><dt><span class="chapter"><a href="#_mount_preparations">4. Mount preparations</a></span></dt><dt><span class="chapter"><a href="#_dracut_on_shutdown">5. Dracut on shutdown</a></span></dt></dl></dd><dt><span class="part"><a href="#_user_manual">II. User Manual</a></span></dt><dd><dl><dt><span class="chapter"><a href="#_dracut_8">6. DRACUT(8)</a></span></dt><dd><dl><dt><span class="section"><a href="#_name">NAME</a></span></dt><dt><span class="section"><a href="#_synopsis">SYNOPSIS</a></span></dt><dt><span class="section"><a href="#_description">DESCRIPTION</a></span></dt><dt><span class="section"><a href="#_usage">USAGE</a></span></dt><dd><dl><dt><span class="section"><a href="#_inspecting_the_contents">Inspecting the Contents</a></span></dt><dt><span class="section"><a href="#_adding_dracut_modules">Adding dracut Modules</a></span></dt><dt><span class="section"><a href="#_omitting_dracut_modules">Omitting dracut Modules</a></span></dt><dt><span class="section"><a href="#_adding_kernel_modules">Adding Kernel Modules</a></span></dt><dt><span class="section"><a href="#_boot_parameters">Boot parameters</a></span></dt><dt><span class="section"><a href="#Injecting">Injecting custom Files</a></span></dt><dt><span class="section"><a href="#NetworkBoot">Network Boot</a></span></dt></dl></dd><dt><span class="section"><a href="#_troubleshooting">Troubleshooting</a></span></dt><dd><dl><dt><span class="section"><a href="#identifying-your-problem-area">Identifying your problem area</a></span></dt><dt><span class="section"><a href="#information-to-include-in-your-report">Information to include in your report</a></span></dt><dt><span class="section"><a href="#debugging-dracut">Debugging dracut</a></span></dt></dl></dd><dt><span class="section"><a href="#_options">OPTIONS</a></span></dt><dt><span class="section"><a href="#_environment">ENVIRONMENT</a></span></dt><dt><span class="section"><a href="#_files">FILES</a></span></dt><dd><dl><dt><span class="section"><a href="#_configuration_in_the_initramfs">Configuration in the initramfs</a></span></dt></dl></dd><dt><span class="section"><a href="#_availability">AVAILABILITY</a></span></dt><dt><span class="section"><a href="#_authors">AUTHORS</a></span></dt><dt><span class="section"><a href="#_see_also">SEE ALSO</a></span></dt></dl></dd><dt><span class="chapter"><a href="#dracutconf5">7. DRACUT.CONF(5)</a></span></dt><dd><dl><dt><span class="section"><a href="#_name_2">NAME</a></span></dt><dt><span class="section"><a href="#_synopsis_2">SYNOPSIS</a></span></dt><dt><span class="section"><a href="#_description_2">Description</a></span></dt><dt><span class="section"><a href="#_files_2">Files</a></span></dt><dt><span class="section"><a href="#_author">AUTHOR</a></span></dt><dt><span class="section"><a href="#_see_also_2">See Also</a></span></dt></dl></dd><dt><span class="chapter"><a href="#dracutcmdline7">8. DRACUT.CMDLINE(7)</a></span></dt><dd><dl><dt><span class="section"><a href="#_name_3">NAME</a></span></dt><dt><span class="section"><a href="#_description_3">DESCRIPTION</a></span></dt><dd><dl><dt><span class="section"><a href="#_standard">Standard</a></span></dt><dt><span class="section"><a href="#_iso_scan_filename">iso-scan/filename</a></span></dt><dt><span class="section"><a href="#_misc">Misc</a></span></dt><dt><span class="section"><a href="#dracutkerneldebug">Debug</a></span></dt><dt><span class="section"><a href="#_i18n">I18N</a></span></dt><dt><span class="section"><a href="#_lvm">LVM</a></span></dt><dt><span class="section"><a href="#_crypto_luks">crypto LUKS</a></span></dt><dt><span class="section"><a href="#_crypto_luks_key_on_removable_device_support">crypto LUKS - key on removable device support</a></span></dt><dt><span class="section"><a href="#_md_raid">MD RAID</a></span></dt><dt><span class="section"><a href="#_dm_raid">DM RAID</a></span></dt><dt><span class="section"><a href="#_multipath">MULTIPATH</a></span></dt><dt><span class="section"><a href="#_fips">FIPS</a></span></dt><dt><span class="section"><a href="#_network">Network</a></span></dt><dt><span class="section"><a href="#_nfs">NFS</a></span></dt><dt><span class="section"><a href="#_cifs">CIFS</a></span></dt><dt><span class="section"><a href="#_iscsi">iSCSI</a></span></dt><dt><span class="section"><a href="#_fcoe">FCoE</a></span></dt><dt><span class="section"><a href="#_nvmf">NVMf</a></span></dt><dt><span class="section"><a href="#_nbd">NBD</a></span></dt><dt><span class="section"><a href="#_virtiofs">VIRTIOFS</a></span></dt><dt><span class="section"><a href="#_dasd">DASD</a></span></dt><dt><span class="section"><a href="#_zfcp">ZFCP</a></span></dt><dt><span class="section"><a href="#_znet">ZNET</a></span></dt><dt><span class="section"><a href="#_booting_live_images">Booting live images</a></span></dt><dt><span class="section"><a href="#_zipl">ZIPL</a></span></dt><dt><span class="section"><a href="#_cio_ignore">CIO_IGNORE</a></span></dt><dt><span class="section"><a href="#_plymouth_boot_splash">Plymouth Boot Splash</a></span></dt><dt><span class="section"><a href="#_kernel_keys">Kernel keys</a></span></dt><dt><span class="section"><a href="#_deprecated_renamed_options">Deprecated, renamed Options</a></span></dt><dt><span class="section"><a href="#_configuration_in_the_initramfs_2">Configuration in the Initramfs</a></span></dt></dl></dd><dt><span class="section"><a href="#_author_2">AUTHOR</a></span></dt><dt><span class="section"><a href="#_see_also_3">SEE ALSO</a></span></dt></dl></dd><dt><span class="chapter"><a href="#lsinitrd1">9. LSINITRD(1)</a></span></dt><dd><dl><dt><span class="section"><a href="#_name_4">NAME</a></span></dt><dt><span class="section"><a href="#_synopsis_3">SYNOPSIS</a></span></dt><dt><span class="section"><a href="#_description_4">DESCRIPTION</a></span></dt><dt><span class="section"><a href="#_options_2">OPTIONS</a></span></dt><dt><span class="section"><a href="#_availability_2">AVAILABILITY</a></span></dt><dt><span class="section"><a href="#_authors_2">AUTHORS</a></span></dt><dt><span class="section"><a href="#_see_also_4">SEE ALSO</a></span></dt></dl></dd><dt><span class="chapter"><a href="#_developer_manual">10. Developer Manual</a></span></dt><dt><span class="chapter"><a href="#dracutmodules7">11. DRACUT.MODULES(7)</a></span></dt><dd><dl><dt><span class="section"><a href="#_name_5">NAME</a></span></dt><dt><span class="section"><a href="#_description_5">DESCRIPTION</a></span></dt><dt><span class="section"><a href="#stages">Boot Process Stages</a></span></dt><dd><dl><dt><span class="section"><a href="#_hook_cmdline">Hook: cmdline</a></span></dt><dt><span class="section"><a href="#_hook_pre_udev">Hook: pre-udev</a></span></dt><dt><span class="section"><a href="#_start_udev">Start Udev</a></span></dt><dt><span class="section"><a href="#_hook_pre_trigger">Hook: pre-trigger</a></span></dt><dt><span class="section"><a href="#_trigger_udev">Trigger Udev</a></span></dt><dt><span class="section"><a href="#_main_loop">Main Loop</a></span></dt><dt><span class="section"><a href="#_hook_pre_mount">Hook: pre-mount</a></span></dt><dt><span class="section"><a href="#_hook_mount">Hook: mount</a></span></dt><dt><span class="section"><a href="#_hook_pre_pivot">Hook: pre-pivot</a></span></dt><dt><span class="section"><a href="#_hook_cleanup">Hook: cleanup</a></span></dt><dt><span class="section"><a href="#_cleanup_and_switch_root">Cleanup and switch_root</a></span></dt></dl></dd><dt><span class="section"><a href="#_network_infrastructure">Network Infrastructure</a></span></dt><dt><span class="section"><a href="#_writing_a_module">Writing a Module</a></span></dt><dd><dl><dt><span class="section"><a href="#_module_setup_sh_check">module-setup.sh: check()</a></span></dt><dt><span class="section"><a href="#_module_setup_sh_depends">module-setup.sh: depends()</a></span></dt><dt><span class="section"><a href="#_module_setup_sh_cmdline">module-setup.sh: cmdline()</a></span></dt><dt><span class="section"><a href="#_module_setup_sh_install">module-setup.sh: install()</a></span></dt><dt><span class="section"><a href="#_module_setup_sh_installkernel">module-setup.sh: installkernel()</a></span></dt><dt><span class="section"><a href="#_anchor_id_creation_xreflabel_creation_creation_functions">Creation Functions</a></span></dt><dt><span class="section"><a href="#_initramfs_functions">Initramfs Functions</a></span></dt><dt><span class="section"><a href="#_network_modules">Network Modules</a></span></dt></dl></dd><dt><span class="section"><a href="#_author_3">AUTHOR</a></span></dt><dt><span class="section"><a href="#_see_also_5">SEE ALSO</a></span></dt></dl></dd><dt><span class="chapter"><a href="#dracutbootup7">12. DRACUT.BOOTUP(7)</a></span></dt><dd><dl><dt><span class="section"><a href="#_name_6">NAME</a></span></dt><dt><span class="section"><a href="#_description_6">DESCRIPTION</a></span></dt><dt><span class="section"><a href="#_author_4">AUTHOR</a></span></dt><dt><span class="section"><a href="#_see_also_6">SEE ALSO</a></span></dt></dl></dd><dt><span class="appendix"><a href="#_license">A. License</a></span></dt></dl></dd></dl></div><div class="part"><div class="titlepage"><div><div><h1 class="title"><a id="_introduction"></a>Part I. Introduction</h1></div></div></div><div class="toc"><p><strong>Table of Contents</strong></p><dl class="toc"><dt><span class="chapter"><a href="#_definition">1. Definition</a></span></dt><dt><span class="chapter"><a href="#_rationale">2. Rationale</a></span></dt><dt><span class="chapter"><a href="#_implementation">3. Implementation</a></span></dt><dt><span class="chapter"><a href="#_mount_preparations">4. Mount preparations</a></span></dt><dt><span class="chapter"><a href="#_dracut_on_shutdown">5. Dracut on shutdown</a></span></dt></dl></div><p>This section is a modified version of
<a class="ulink" href="http://en.wikipedia.org/wiki/Initrd" target="_top">http://en.wikipedia.org/wiki/Initrd</a> which is licensed under the
Creative Commons Attribution/Share-Alike License.</p><div class="chapter"><div class="titlepage"><div><div><h2 class="title"><a id="_definition"></a>Chapter 1. Definition</h2></div></div></div><p>An <span class="emphasis"><em>initial ramdisk</em></span> is a temporary file system used in the boot process of the
Linux kernel. <span class="emphasis"><em>initrd</em></span> and <span class="emphasis"><em>initramfs</em></span> refer to slightly different schemes for
loading this file system into memory. Both are commonly used to make
preparations before the real root file system can be mounted.</p></div><div class="chapter"><div class="titlepage"><div><div><h2 class="title"><a id="_rationale"></a>Chapter 2. Rationale</h2></div></div></div><p>Many Linux distributions ship a single, generic kernel image that is intended to
boot as wide a variety of hardware as possible. The device drivers for this
generic kernel image are included as loadable modules, as it is not possible to
statically compile them all into the one kernel without making it too large to
boot from computers with limited memory or from lower-capacity media like floppy
disks.</p><p>This then raises the problem of detecting and loading the modules necessary to
mount the root file system at boot time (or, for that matter, deducing where or
what the root file system is).</p><p>To further complicate matters, the root file system may be on a software RAID
volume, LVM, NFS (on diskless workstations), or on an encrypted partition. All
of these require special preparations to mount.</p><p>Another complication is kernel support for hibernation, which suspends the
computer to disk by dumping an image of the entire system to a swap partition or
a regular file, then powering off. On next boot, this image has to be made
accessible before it can be loaded back into memory.</p><p>To avoid having to hardcode handling for so many special cases into the kernel,
an initial boot stage with a temporary root file system
—now dubbed early user space— is used. This root file system would contain
user-space helpers that would do the hardware detection, module loading and
device discovery necessary to get the real root file system mounted.</p></div><div class="chapter"><div class="titlepage"><div><div><h2 class="title"><a id="_implementation"></a>Chapter 3. Implementation</h2></div></div></div><p>An image of this initial root file system (along with the kernel image) must be
stored somewhere accessible by the Linux bootloader or the boot firmware of the
computer. This can be:</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">
The root file system itself
</li><li class="listitem">
A boot image on an optical disc
</li><li class="listitem">
A small ext2/ext3 or FAT-formatted partition on a local disk
(a <span class="emphasis"><em>boot partition</em></span>)
</li><li class="listitem">
A TFTP server (on systems that can boot from Ethernet)
</li></ul></div><p>The bootloader will load the kernel and initial root file system image into
memory and then start the kernel, passing in the memory address of the image.</p><p>Depending on which algorithms were compiled statically into it, the kernel can
currently unpack initrd/initramfs images compressed with gzip, bzip2 and LZMA.</p></div><div class="chapter"><div class="titlepage"><div><div><h2 class="title"><a id="_mount_preparations"></a>Chapter 4. Mount preparations</h2></div></div></div><p>dracut can generate a customized initramfs image which contains only whatever is
necessary to boot some particular computer, such as ATA, SCSI and filesystem
kernel modules (host-only mode).</p><p>dracut can also generate a more generic initramfs image (default mode).</p><p>dracut’s initramfs starts only with the device name of the root file system (or
its UUID) and must discover everything else at boot time. A complex cascade of
tasks must be performed to get the root file system mounted:</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">
Any hardware drivers that the boot process depends on must be loaded. All
kernel modules for common storage devices are packed onto the initramfs and then
udev pulls in modules matching the computer’s detected hardware.
</li><li class="listitem">
On systems which display a boot rd.splash screen, the video hardware must be
initialized and a user-space helper started to paint animations onto the display
in lockstep with the boot process.
</li><li class="listitem"><p class="simpara">
If the root file system is on NFS, dracut does then:
</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: circle; "><li class="listitem">
Bring up the primary network interface.
</li><li class="listitem">
Invoke a DHCP client, with which it can obtain a DHCP lease.
</li><li class="listitem">
Extract the name of the NFS share and the address of the NFS server from the
lease.
</li><li class="listitem">
Mount the NFS share.
</li></ul></div></li><li class="listitem">
If the root file system appears to be on a software RAID device, there is no
way of knowing which devices the RAID volume spans; the standard MD utilities
must be invoked to scan all available block devices with a raid signature and
bring the required ones online.
</li><li class="listitem">
If the root file system appears to be on a logical volume, the LVM utilities
must be invoked to scan for and activate the volume group containing it.
</li><li class="listitem"><p class="simpara">
If the root file system is on an encrypted block device:
</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: circle; "><li class="listitem">
Invoke a helper script to prompt the user to type in a passphrase and/or
insert a hardware token (such as a smart card or a USB security dongle).
</li></ul></div></li><li class="listitem">
Create a decryption target with the device mapper.
</li></ul></div><p>dracut uses udev, an event-driven hotplug agent, which invokes helper programs
as hardware devices, disk partitions and storage volumes matching certain rules
come online. This allows discovery to run in parallel, and to progressively
cascade into arbitrary nestings of LVM, RAID or encryption to get at the root
file system.</p><p>When the root file system finally becomes visible:</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">
Any maintenance tasks which cannot run on a mounted root file system
are done.
</li><li class="listitem">
The root file system is mounted read-only.
</li><li class="listitem">
Any processes which must continue running (such as the rd.splash screen helper
and its command FIFO) are hoisted into the newly-mounted root file system.
</li></ul></div><p>The final root file system cannot simply be mounted over /, since that would
make the scripts and tools on the initial root file system inaccessible for any
final cleanup tasks. On an initramfs, the initial root file system cannot be
rotated away. Instead, it is simply emptied and the final root file system
mounted over the top.</p><p>If the systemd module is used in the initramfs, the ordering of the services
started looks like <a class="xref" href="#dracutbootup7" title="Chapter 12. DRACUT.BOOTUP(7)">Chapter 12, <em>DRACUT.BOOTUP(7)</em></a>.</p></div><div class="chapter"><div class="titlepage"><div><div><h2 class="title"><a id="_dracut_on_shutdown"></a>Chapter 5. Dracut on shutdown</h2></div></div></div><p>On a systemd driven system, the dracut initramfs is also used for the shutdown
procedure.</p><p>The following steps are executed during a shutdown:</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">
systemd switches to the shutdown.target
</li><li class="listitem">
systemd starts
$prefix/lib/systemd/system/shutdown.target.wants/dracut-shutdown.service
</li><li class="listitem">
dracut-shutdown.service executes /usr/lib/dracut/dracut-initramfs-restore
which unpacks the initramfs to /run/initramfs
</li><li class="listitem">
systemd finishes shutdown.target
</li><li class="listitem">
systemd kills all processes
</li><li class="listitem">
systemd tries to unmount everything and mounts the remaining read-only
</li><li class="listitem">
systemd checks, if there is a /run/initramfs/shutdown executable
</li><li class="listitem">
if yes, it does a pivot_root to /run/initramfs and executes ./shutdown.
The old root is then mounted on /oldroot.
/usr/lib/dracut/modules.d/99shutdown/shutdown.sh is the shutdown executable.
</li><li class="listitem">
shutdown will try to unmount every /oldroot mount and calls the various
shutdown hooks from the dracut modules
</li></ul></div><p>This ensures, that all devices are disassembled and unmounted cleanly.</p></div></div><div class="part"><div class="titlepage"><div><div><h1 class="title"><a id="_user_manual"></a>Part II. User Manual</h1></div></div></div><div class="toc"><p><strong>Table of Contents</strong></p><dl class="toc"><dt><span class="chapter"><a href="#_dracut_8">6. DRACUT(8)</a></span></dt><dd><dl><dt><span class="section"><a href="#_name">NAME</a></span></dt><dt><span class="section"><a href="#_synopsis">SYNOPSIS</a></span></dt><dt><span class="section"><a href="#_description">DESCRIPTION</a></span></dt><dt><span class="section"><a href="#_usage">USAGE</a></span></dt><dd><dl><dt><span class="section"><a href="#_inspecting_the_contents">Inspecting the Contents</a></span></dt><dt><span class="section"><a href="#_adding_dracut_modules">Adding dracut Modules</a></span></dt><dt><span class="section"><a href="#_omitting_dracut_modules">Omitting dracut Modules</a></span></dt><dt><span class="section"><a href="#_adding_kernel_modules">Adding Kernel Modules</a></span></dt><dt><span class="section"><a href="#_boot_parameters">Boot parameters</a></span></dt><dt><span class="section"><a href="#Injecting">Injecting custom Files</a></span></dt><dt><span class="section"><a href="#NetworkBoot">Network Boot</a></span></dt></dl></dd><dt><span class="section"><a href="#_troubleshooting">Troubleshooting</a></span></dt><dd><dl><dt><span class="section"><a href="#identifying-your-problem-area">Identifying your problem area</a></span></dt><dt><span class="section"><a href="#information-to-include-in-your-report">Information to include in your report</a></span></dt><dt><span class="section"><a href="#debugging-dracut">Debugging dracut</a></span></dt></dl></dd><dt><span class="section"><a href="#_options">OPTIONS</a></span></dt><dt><span class="section"><a href="#_environment">ENVIRONMENT</a></span></dt><dt><span class="section"><a href="#_files">FILES</a></span></dt><dd><dl><dt><span class="section"><a href="#_configuration_in_the_initramfs">Configuration in the initramfs</a></span></dt></dl></dd><dt><span class="section"><a href="#_availability">AVAILABILITY</a></span></dt><dt><span class="section"><a href="#_authors">AUTHORS</a></span></dt><dt><span class="section"><a href="#_see_also">SEE ALSO</a></span></dt></dl></dd><dt><span class="chapter"><a href="#dracutconf5">7. DRACUT.CONF(5)</a></span></dt><dd><dl><dt><span class="section"><a href="#_name_2">NAME</a></span></dt><dt><span class="section"><a href="#_synopsis_2">SYNOPSIS</a></span></dt><dt><span class="section"><a href="#_description_2">Description</a></span></dt><dt><span class="section"><a href="#_files_2">Files</a></span></dt><dt><span class="section"><a href="#_author">AUTHOR</a></span></dt><dt><span class="section"><a href="#_see_also_2">See Also</a></span></dt></dl></dd><dt><span class="chapter"><a href="#dracutcmdline7">8. DRACUT.CMDLINE(7)</a></span></dt><dd><dl><dt><span class="section"><a href="#_name_3">NAME</a></span></dt><dt><span class="section"><a href="#_description_3">DESCRIPTION</a></span></dt><dd><dl><dt><span class="section"><a href="#_standard">Standard</a></span></dt><dt><span class="section"><a href="#_iso_scan_filename">iso-scan/filename</a></span></dt><dt><span class="section"><a href="#_misc">Misc</a></span></dt><dt><span class="section"><a href="#dracutkerneldebug">Debug</a></span></dt><dt><span class="section"><a href="#_i18n">I18N</a></span></dt><dt><span class="section"><a href="#_lvm">LVM</a></span></dt><dt><span class="section"><a href="#_crypto_luks">crypto LUKS</a></span></dt><dt><span class="section"><a href="#_crypto_luks_key_on_removable_device_support">crypto LUKS - key on removable device support</a></span></dt><dt><span class="section"><a href="#_md_raid">MD RAID</a></span></dt><dt><span class="section"><a href="#_dm_raid">DM RAID</a></span></dt><dt><span class="section"><a href="#_multipath">MULTIPATH</a></span></dt><dt><span class="section"><a href="#_fips">FIPS</a></span></dt><dt><span class="section"><a href="#_network">Network</a></span></dt><dt><span class="section"><a href="#_nfs">NFS</a></span></dt><dt><span class="section"><a href="#_cifs">CIFS</a></span></dt><dt><span class="section"><a href="#_iscsi">iSCSI</a></span></dt><dt><span class="section"><a href="#_fcoe">FCoE</a></span></dt><dt><span class="section"><a href="#_nvmf">NVMf</a></span></dt><dt><span class="section"><a href="#_nbd">NBD</a></span></dt><dt><span class="section"><a href="#_virtiofs">VIRTIOFS</a></span></dt><dt><span class="section"><a href="#_dasd">DASD</a></span></dt><dt><span class="section"><a href="#_zfcp">ZFCP</a></span></dt><dt><span class="section"><a href="#_znet">ZNET</a></span></dt><dt><span class="section"><a href="#_booting_live_images">Booting live images</a></span></dt><dt><span class="section"><a href="#_zipl">ZIPL</a></span></dt><dt><span class="section"><a href="#_cio_ignore">CIO_IGNORE</a></span></dt><dt><span class="section"><a href="#_plymouth_boot_splash">Plymouth Boot Splash</a></span></dt><dt><span class="section"><a href="#_kernel_keys">Kernel keys</a></span></dt><dt><span class="section"><a href="#_deprecated_renamed_options">Deprecated, renamed Options</a></span></dt><dt><span class="section"><a href="#_configuration_in_the_initramfs_2">Configuration in the Initramfs</a></span></dt></dl></dd><dt><span class="section"><a href="#_author_2">AUTHOR</a></span></dt><dt><span class="section"><a href="#_see_also_3">SEE ALSO</a></span></dt></dl></dd><dt><span class="chapter"><a href="#lsinitrd1">9. LSINITRD(1)</a></span></dt><dd><dl><dt><span class="section"><a href="#_name_4">NAME</a></span></dt><dt><span class="section"><a href="#_synopsis_3">SYNOPSIS</a></span></dt><dt><span class="section"><a href="#_description_4">DESCRIPTION</a></span></dt><dt><span class="section"><a href="#_options_2">OPTIONS</a></span></dt><dt><span class="section"><a href="#_availability_2">AVAILABILITY</a></span></dt><dt><span class="section"><a href="#_authors_2">AUTHORS</a></span></dt><dt><span class="section"><a href="#_see_also_4">SEE ALSO</a></span></dt></dl></dd><dt><span class="chapter"><a href="#_developer_manual">10. Developer Manual</a></span></dt><dt><span class="chapter"><a href="#dracutmodules7">11. DRACUT.MODULES(7)</a></span></dt><dd><dl><dt><span class="section"><a href="#_name_5">NAME</a></span></dt><dt><span class="section"><a href="#_description_5">DESCRIPTION</a></span></dt><dt><span class="section"><a href="#stages">Boot Process Stages</a></span></dt><dd><dl><dt><span class="section"><a href="#_hook_cmdline">Hook: cmdline</a></span></dt><dt><span class="section"><a href="#_hook_pre_udev">Hook: pre-udev</a></span></dt><dt><span class="section"><a href="#_start_udev">Start Udev</a></span></dt><dt><span class="section"><a href="#_hook_pre_trigger">Hook: pre-trigger</a></span></dt><dt><span class="section"><a href="#_trigger_udev">Trigger Udev</a></span></dt><dt><span class="section"><a href="#_main_loop">Main Loop</a></span></dt><dt><span class="section"><a href="#_hook_pre_mount">Hook: pre-mount</a></span></dt><dt><span class="section"><a href="#_hook_mount">Hook: mount</a></span></dt><dt><span class="section"><a href="#_hook_pre_pivot">Hook: pre-pivot</a></span></dt><dt><span class="section"><a href="#_hook_cleanup">Hook: cleanup</a></span></dt><dt><span class="section"><a href="#_cleanup_and_switch_root">Cleanup and switch_root</a></span></dt></dl></dd><dt><span class="section"><a href="#_network_infrastructure">Network Infrastructure</a></span></dt><dt><span class="section"><a href="#_writing_a_module">Writing a Module</a></span></dt><dd><dl><dt><span class="section"><a href="#_module_setup_sh_check">module-setup.sh: check()</a></span></dt><dt><span class="section"><a href="#_module_setup_sh_depends">module-setup.sh: depends()</a></span></dt><dt><span class="section"><a href="#_module_setup_sh_cmdline">module-setup.sh: cmdline()</a></span></dt><dt><span class="section"><a href="#_module_setup_sh_install">module-setup.sh: install()</a></span></dt><dt><span class="section"><a href="#_module_setup_sh_installkernel">module-setup.sh: installkernel()</a></span></dt><dt><span class="section"><a href="#_anchor_id_creation_xreflabel_creation_creation_functions">Creation Functions</a></span></dt><dt><span class="section"><a href="#_initramfs_functions">Initramfs Functions</a></span></dt><dt><span class="section"><a href="#_network_modules">Network Modules</a></span></dt></dl></dd><dt><span class="section"><a href="#_author_3">AUTHOR</a></span></dt><dt><span class="section"><a href="#_see_also_5">SEE ALSO</a></span></dt></dl></dd><dt><span class="chapter"><a href="#dracutbootup7">12. DRACUT.BOOTUP(7)</a></span></dt><dd><dl><dt><span class="section"><a href="#_name_6">NAME</a></span></dt><dt><span class="section"><a href="#_description_6">DESCRIPTION</a></span></dt><dt><span class="section"><a href="#_author_4">AUTHOR</a></span></dt><dt><span class="section"><a href="#_see_also_6">SEE ALSO</a></span></dt></dl></dd><dt><span class="appendix"><a href="#_license">A. License</a></span></dt></dl></div><div class="chapter"><div class="titlepage"><div><div><h2 class="title"><a id="_dracut_8"></a>Chapter 6. DRACUT(8)</h2></div></div></div><div class="toc"><p><strong>Table of Contents</strong></p><dl class="toc"><dt><span class="section"><a href="#_name">NAME</a></span></dt><dt><span class="section"><a href="#_synopsis">SYNOPSIS</a></span></dt><dt><span class="section"><a href="#_description">DESCRIPTION</a></span></dt><dt><span class="section"><a href="#_usage">USAGE</a></span></dt><dd><dl><dt><span class="section"><a href="#_inspecting_the_contents">Inspecting the Contents</a></span></dt><dt><span class="section"><a href="#_adding_dracut_modules">Adding dracut Modules</a></span></dt><dt><span class="section"><a href="#_omitting_dracut_modules">Omitting dracut Modules</a></span></dt><dt><span class="section"><a href="#_adding_kernel_modules">Adding Kernel Modules</a></span></dt><dt><span class="section"><a href="#_boot_parameters">Boot parameters</a></span></dt><dt><span class="section"><a href="#Injecting">Injecting custom Files</a></span></dt><dt><span class="section"><a href="#NetworkBoot">Network Boot</a></span></dt></dl></dd><dt><span class="section"><a href="#_troubleshooting">Troubleshooting</a></span></dt><dd><dl><dt><span class="section"><a href="#identifying-your-problem-area">Identifying your problem area</a></span></dt><dt><span class="section"><a href="#information-to-include-in-your-report">Information to include in your report</a></span></dt><dt><span class="section"><a href="#debugging-dracut">Debugging dracut</a></span></dt></dl></dd><dt><span class="section"><a href="#_options">OPTIONS</a></span></dt><dt><span class="section"><a href="#_environment">ENVIRONMENT</a></span></dt><dt><span class="section"><a href="#_files">FILES</a></span></dt><dd><dl><dt><span class="section"><a href="#_configuration_in_the_initramfs">Configuration in the initramfs</a></span></dt></dl></dd><dt><span class="section"><a href="#_availability">AVAILABILITY</a></span></dt><dt><span class="section"><a href="#_authors">AUTHORS</a></span></dt><dt><span class="section"><a href="#_see_also">SEE ALSO</a></span></dt></dl></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="_name"></a>NAME</h2></div></div></div><p>dracut - low-level tool for generating an initramfs/initrd image</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="_synopsis"></a>SYNOPSIS</h2></div></div></div><p><span class="strong"><strong>dracut</strong></span> [<span class="emphasis"><em>OPTION…</em></span>] [<span class="emphasis"><em><image></em></span> [<span class="emphasis"><em><kernel version></em></span>]]</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="_description"></a>DESCRIPTION</h2></div></div></div><p>Create an initramfs <image> for the kernel with the version <kernel version>.
If <kernel version> is omitted, then the version of the actual running
kernel is used. If <image> is omitted or empty, depending on bootloader
specification, the default location can be
<span class="emphasis"><em>/efi/<machine-id>/<kernel-version>/initrd</em></span>,
<span class="emphasis"><em>/boot/<machine-id>/<kernel-version>/initrd</em></span>,
<span class="emphasis"><em>/boot/efi/<machine-id>/<kernel-version>/initrd</em></span>,
<span class="emphasis"><em>/lib/modules/<kernel-version>/initrd</em></span> or
<span class="emphasis"><em>/boot/initramfs-<kernel-version>.img</em></span>.</p><p>dracut creates an initial image used by the kernel for preloading the block
device modules (such as IDE, SCSI or RAID) which are needed to access the root
filesystem, mounting the root filesystem and booting into the real system.</p><p>At boot time, the kernel unpacks that archive into RAM disk, mounts and uses it
as initial root file system. All finding of the root device happens in this
early userspace.</p><p>Initramfs images are also called "initrd".</p><p>For a complete list of kernel command line options see <span class="strong"><strong>dracut.cmdline</strong></span>(7).</p><p>If you are dropped to an emergency shell, while booting your initramfs,
the file <span class="emphasis"><em>/run/initramfs/rdsosreport.txt</em></span> is created, which can be saved to a
(to be mounted by hand) partition (usually /boot) or a USB stick.
Additional debugging info can be produced by adding <span class="strong"><strong>rd.debug</strong></span> to the kernel
command line. <span class="emphasis"><em>/run/initramfs/rdsosreport.txt</em></span> contains all logs and the output
of some tools. It should be attached to any report about dracut problems.</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="_usage"></a>USAGE</h2></div></div></div><p>To create a initramfs image, the most simple command is:</p><pre class="screen"># dracut</pre><p>This will generate a general purpose initramfs image, with all possible
functionality resulting of the combination of the installed dracut modules and
system tools. The image, depending on bootloader specification, can be
<span class="emphasis"><em>/efi/</em></span><code class="literal"><machine-id></code><span class="emphasis"><em>/</em></span><code class="literal"><kernel-version></code><span class="emphasis"><em>/initrd</em></span>,
<span class="emphasis"><em>/boot/</em></span><code class="literal"><machine-id></code><span class="emphasis"><em>/</em></span><code class="literal"><kernel-version></code><span class="emphasis"><em>/initrd</em></span>,
<span class="emphasis"><em>/boot/efi/</em></span><code class="literal"><machine-id></code><span class="emphasis"><em>/</em></span><code class="literal"><kernel-version></code><span class="emphasis"><em>/initrd</em></span>,
<span class="emphasis"><em>/lib/modules/</em></span><code class="literal"><kernel-version></code><span class="emphasis"><em>/initrd</em></span> or
<span class="emphasis"><em>/boot/initramfs-</em></span><code class="literal"><kernel-version></code><span class="emphasis"><em>.img</em></span> and contains the kernel modules of
the currently active kernel with version <span class="emphasis"><em><code class="literal"><kernel-version></code></em></span>.</p><p>If the initramfs image already exists, dracut will display an error message, and
to overwrite the existing image, you have to use the --force option.</p><pre class="screen"># dracut --force</pre><p>If you want to specify another filename for the resulting image you would issue
a command like:</p><pre class="screen"># dracut foobar.img</pre><p>To generate an image for a specific kernel version, the command would be:</p><pre class="screen"># dracut foobar.img 2.6.40-1.rc5.f20</pre><p>A shortcut to generate the image at the default location for a specific kernel
version is:</p><pre class="screen"># dracut --kver 2.6.40-1.rc5.f20</pre><p>If you want to create lighter, smaller initramfs images, you may want to specify
the --hostonly or -H option. Using this option, the resulting image will
contain only those dracut modules, kernel modules and filesystems, which are
needed to boot this specific machine. This has the drawback, that you can’t put
the disk on another controller or machine, and that you can’t switch to another
root filesystem, without recreating the initramfs image. The usage of the
--hostonly option is only for experts and you will have to keep the broken
pieces. At least keep a copy of a general purpose image (and corresponding
kernel) as a fallback to rescue your system.</p><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_inspecting_the_contents"></a>Inspecting the Contents</h3></div></div></div><p>To see the contents of the image created by dracut, you can use the lsinitrd
tool.</p><pre class="screen"># lsinitrd | less</pre><p>To display the contents of a file in the initramfs also use the lsinitrd tool:</p><pre class="screen"># lsinitrd -f /etc/ld.so.conf
include ld.so.conf.d/*.conf</pre></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_adding_dracut_modules"></a>Adding dracut Modules</h3></div></div></div><p>Some dracut modules are turned off by default and have to be activated manually.
You can do this by adding the dracut modules to the configuration file
<span class="emphasis"><em>/etc/dracut.conf</em></span> or <span class="emphasis"><em>/etc/dracut.conf.d/myconf.conf</em></span>. See <span class="strong"><strong>dracut.conf</strong></span>(5).
You can also add dracut modules on the command line
by using the -a or --add option:</p><pre class="screen"># dracut --add module initramfs-module.img</pre><p>To see a list of available dracut modules, use the --list-modules option:</p><pre class="screen"># dracut --list-modules</pre></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_omitting_dracut_modules"></a>Omitting dracut Modules</h3></div></div></div><p>Sometimes you don’t want a dracut module to be included for reasons of speed,
size or functionality. To do this, either specify the omit_dracutmodules
variable in the <span class="emphasis"><em>dracut.conf</em></span> or <span class="emphasis"><em>/etc/dracut.conf.d/myconf.conf</em></span> configuration
file (see <span class="strong"><strong>dracut.conf</strong></span>(5)), or use the -o or --omit option
on the command line:</p><pre class="screen"># dracut -o "multipath lvm" no-multipath-lvm.img</pre></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_adding_kernel_modules"></a>Adding Kernel Modules</h3></div></div></div><p>If you need a special kernel module in the initramfs, which is not
automatically picked up by dracut, you have the use the --add-drivers option
on the command line or the drivers variable in the <span class="emphasis"><em>/etc/dracut.conf</em></span>
or <span class="emphasis"><em>/etc/dracut.conf.d/myconf.conf</em></span> configuration file (see <span class="strong"><strong>dracut.conf</strong></span>(5)):</p><pre class="screen"># dracut --add-drivers mymod initramfs-with-mymod.img</pre></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_boot_parameters"></a>Boot parameters</h3></div></div></div><p>An initramfs generated without the "hostonly" mode, does not contain any system
configuration files (except for some special exceptions), so the configuration
has to be done on the kernel command line. With this flexibility, you can easily
boot from a changed root partition, without the need to recompile the initramfs
image. So, you could completely change your root partition (move it inside a md
raid with encryption and LVM on top), as long as you specify the correct
filesystem LABEL or UUID on the kernel command line for your root device, dracut
will find it and boot from it.</p><p>The kernel command line can also be provided by the dhcp server with the
root-path option. See <a class="xref" href="#NetworkBoot" title="Network Boot">the section called “Network Boot”</a>.</p><p>For a full reference of all kernel command line parameters,
see <span class="strong"><strong>dracut.cmdline</strong></span>(7).</p><p>To get a quick start for the suitable kernel command line on your system,
use the <span class="emphasis"><em>--print-cmdline</em></span> option:</p><pre class="screen"># dracut --print-cmdline
root=UUID=8b8b6f91-95c7-4da2-831b-171e12179081 rootflags=rw,relatime,discard,data=ordered rootfstype=ext4</pre><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="_specifying_the_root_device"></a>Specifying the root Device</h4></div></div></div><p>This is the only option dracut really needs to boot from your root partition.
Because your root partition can live in various environments, there are a lot of
formats for the root= option. The most basic one is root=<span class="emphasis"><em><code class="literal"><path to device
node></code></em></span>:</p><pre class="screen">root=/dev/sda2</pre><p>Because device node names can change, dependent on the drive ordering, you are
encouraged to use the filesystem identifier (UUID) or filesystem label (LABEL)
to specify your root partition:</p><pre class="screen">root=UUID=19e9dda3-5a38-484d-a9b0-fa6b067d0331</pre><p>or</p><pre class="screen">root=LABEL=myrootpartitionlabel</pre><p>To see all UUIDs or LABELs on your system, do:</p><pre class="screen"># ls -l /dev/disk/by-uuid</pre><p>or</p><pre class="screen"># ls -l /dev/disk/by-label</pre><p>If your root partition is on the network see <a class="xref" href="#NetworkBoot" title="Network Boot">the section called “Network Boot”</a>.</p></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="_keyboard_settings"></a>Keyboard Settings</h4></div></div></div><p>If you have to input passwords for encrypted disk volumes, you might want to set
the keyboard layout and specify a display font.</p><p>A typical german kernel command line would contain:</p><pre class="screen">rd.vconsole.font=eurlatgr rd.vconsole.keymap=de-latin1-nodeadkeys rd.locale.LANG=de_DE.UTF-8</pre><p>Setting these options can override the setting stored on your system, if you use
a modern init system, like systemd.</p></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="_blacklisting_kernel_modules"></a>Blacklisting Kernel Modules</h4></div></div></div><p>Sometimes it is required to prevent the automatic kernel module loading of a
specific kernel module. To do this, just add rd.blacklist=<span class="emphasis"><em><code class="literal"><kernel module
name></code></em></span>, with <span class="emphasis"><em><code class="literal"><kernel module name></code></em></span> not containing the <span class="emphasis"><em>.ko</em></span>
suffix, to the kernel command line. For example:</p><pre class="screen">rd.driver.blacklist=mptsas rd.driver.blacklist=nouveau</pre><p>The option can be specified multiple times on the kernel command line.</p></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="_speeding_up_the_boot_process"></a>Speeding up the Boot Process</h4></div></div></div><p>If you want to speed up the boot process, you can specify as much information
for dracut on the kernel command as possible. For example, you can tell dracut,
that you root partition is not on a LVM volume or not on a raid partition, or
that it lives inside a specific crypto LUKS encrypted volume. By default, dracut
searches everywhere. A typical dracut kernel command line for a plain primary or
logical partition would contain:</p><pre class="screen">rd.luks=0 rd.lvm=0 rd.md=0 rd.dm=0</pre><p>This turns off every automatic assembly of LVM, MD raids, DM raids and
crypto LUKS.</p><p>Of course, you could also omit the dracut modules in the initramfs creation
process, but then you would lose the possibility to turn it on on demand.</p></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="Injecting"></a>Injecting custom Files</h3></div></div></div><p>To add your own files to the initramfs image, you have several possibilities.</p><p>The --include option let you specify a source path and a target path.
For example</p><pre class="screen"># dracut --include cmdline-preset /etc/cmdline.d/mycmdline.conf initramfs-cmdline-pre.img</pre><p>will create an initramfs image, where the file cmdline-preset will be copied
inside the initramfs to <span class="emphasis"><em>/etc/cmdline.d/mycmdline.conf</em></span>. --include can only
be specified once.</p><pre class="screen"># mkdir -p rd.live.overlay/etc/cmdline.d
# mkdir -p rd.live.overlay/etc/conf.d
# echo "ip=dhcp" >> rd.live.overlay/etc/cmdline.d/mycmdline.conf
# echo export FOO=testtest >> rd.live.overlay/etc/conf.d/testvar.conf
# echo export BAR=testtest >> rd.live.overlay/etc/conf.d/testvar.conf
# tree rd.live.overlay/
rd.live.overlay/
`-- etc
|-- cmdline.d
| `-- mycmdline.conf
`-- conf.d
`-- testvar.conf
# dracut --include rd.live.overlay / initramfs-rd.live.overlay.img</pre><p>This will put the contents of the rd.live.overlay directory into the root of the
initramfs image.</p><p>The --install option let you specify several files, which will get installed in
the initramfs image at the same location, as they are present on initramfs
creation time.</p><pre class="screen"># dracut --install 'strace fsck.ext3 ssh' initramfs-dbg.img</pre><p>This will create an initramfs with the strace, fsck.ext3 and ssh executables,
together with the libraries needed to start those. The --install option can be
specified multiple times.</p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="NetworkBoot"></a>Network Boot</h3></div></div></div><p>If your root partition is on a network drive, you have to have the network
dracut modules installed to create a network aware initramfs image.</p><p>If you specify ip=dhcp on the kernel command line, then dracut asks a dhcp
server about the ip address for the machine. The dhcp server can also serve an
additional root-path, which will set the root device for dracut. With this
mechanism, you have static configuration on your client machine and a
centralized boot configuration on your TFTP/DHCP server. If you can’t pass a
kernel command line, then you can inject <span class="emphasis"><em>/etc/cmdline.d/mycmdline.conf</em></span>, with a
method described in <a class="xref" href="#Injecting" title="Injecting custom Files">the section called “Injecting custom Files”</a>.</p><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="_reducing_the_image_size"></a>Reducing the Image Size</h4></div></div></div><p>To reduce the size of the initramfs, you should create it with by omitting all
dracut modules, which you know, you don’t need to boot the machine.</p><p>You can also specify the exact dracut and kernel modules to produce a very tiny
initramfs image.</p><p>For example for a NFS image, you would do:</p><pre class="screen"># dracut -m "nfs network base" initramfs-nfs-only.img</pre><p>Then you would boot from this image with your target machine and reduce the size
once more by creating it on the target machine with the --host-only option:</p><pre class="screen"># dracut -m "nfs network base" --host-only initramfs-nfs-host-only.img</pre><p>This will reduce the size of the initramfs image significantly.</p></div></div></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="_troubleshooting"></a>Troubleshooting</h2></div></div></div><p>If the boot process does not succeed, you have several options to debug the
situation. Some of the basic operations are covered here. For more information
you should also visit:
<a class="ulink" href="https://www.kernel.org/pub/linux/utils/boot/dracut/dracut.html" target="_top">https://www.kernel.org/pub/linux/utils/boot/dracut/dracut.html</a></p><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="identifying-your-problem-area"></a>Identifying your problem area</h3></div></div></div><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem">
Remove <span class="emphasis"><em>'rhgb</em></span>' and <span class="emphasis"><em>'quiet</em></span>' from the kernel command line
</li><li class="listitem">
Add <span class="emphasis"><em>'rd.shell</em></span>' to the kernel command line. This will present a shell should
dracut be unable to locate your root device
</li><li class="listitem">
Add <span class="emphasis"><em>'rd.shell rd.debug log_buf_len=1M</em></span>' to the kernel command line so that
dracut shell commands are printed as they are executed
</li><li class="listitem">
The file /run/initramfs/rdsosreport.txt is generated,
which contains all the logs and the output of all significant tools, which are
mentioned later.
</li></ol></div><p>If you want to save that output, simply mount /boot by hand or insert an USB
stick and mount that. Then you can store the output for later inspection.</p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="information-to-include-in-your-report"></a>Information to include in your report</h3></div></div></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="all-bug-reports"></a>All bug reports</h4></div></div></div><p>In all cases, the following should be mentioned and attached to your bug report:</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">
The exact kernel command-line used. Typically from the bootloader
configuration file (e.g. <span class="emphasis"><em>/boot/grub2/grub.cfg</em></span>) or from <span class="emphasis"><em>/proc/cmdline</em></span>.
</li><li class="listitem">
A copy of your disk partition information from <span class="emphasis"><em>/etc/fstab</em></span>, which might be
obtained booting an old working initramfs or a rescue medium.
</li><li class="listitem">
Turn on dracut debugging (see <span class="emphasis"><em>the <span class="emphasis"><em>debugging dracut</em></span> section</em></span>), and attach
the file /run/initramfs/rdsosreport.txt.
</li><li class="listitem">
If you use a dracut configuration file, please include <span class="emphasis"><em>/etc/dracut.conf</em></span> and
all files in <span class="emphasis"><em>/etc/dracut.conf.d/*.conf</em></span>
</li></ul></div></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="network-root-device-related-problems"></a>Network root device related problems</h4></div></div></div><p>This section details information to include when experiencing problems on a
system whose root device is located on a network attached volume (e.g. iSCSI,
NFS or NBD). As well as the information from <a class="xref" href="#all-bug-reports" title="All bug reports">the section called “All bug reports”</a>, include the
following information:</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p class="simpara">
Please include the output of
</p><pre class="screen"># /sbin/ifup <interfacename>
# ip addr show</pre></li></ul></div></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="debugging-dracut"></a>Debugging dracut</h3></div></div></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="configure-a-serial-console"></a>Configure a serial console</h4></div></div></div><p>Successfully debugging dracut will require some form of console
logging during the system boot. This section documents configuring a
serial console connection to record boot messages.</p><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem">
First, enable serial console output for both the kernel and the bootloader.
</li><li class="listitem"><p class="simpara">
Open the file <span class="emphasis"><em>/boot/grub2/grub.cfg</em></span> for editing. Below the line <span class="emphasis"><em>'timeout=5</em></span>', add
the following:
</p><pre class="screen">serial --unit=0 --speed=9600
terminal --timeout=5 serial console</pre></li><li class="listitem"><p class="simpara">
Also in <span class="emphasis"><em>/boot/grub2/grub.cfg</em></span>, add the following boot arguments to the <span class="emphasis"><em>'kernel</em></span>'
line:
</p><pre class="screen">console=tty0 console=ttyS0,9600</pre></li><li class="listitem"><p class="simpara">
When finished, the <span class="emphasis"><em>/boot/grub2/grub.cfg</em></span> file should look similar to the example
below.
</p><pre class="screen">default=0
timeout=5
serial --unit=0 --speed=9600
terminal --timeout=5 serial console
title Fedora (2.6.29.5-191.fc11.x86_64)
root (hd0,0)
kernel /vmlinuz-2.6.29.5-191.fc11.x86_64 ro root=/dev/mapper/vg_uc1-lv_root console=tty0 console=ttyS0,9600
initrd /dracut-2.6.29.5-191.fc11.x86_64.img</pre></li><li class="listitem">
More detailed information on how to configure the kernel for console output
can be found at
<a class="ulink" href="http://www.faqs.org/docs/Linux-HOWTO/Remote-Serial-Console-HOWTO.html#CONFIGURE-KERNEL" target="_top">http://www.faqs.org/docs/Linux-HOWTO/Remote-Serial-Console-HOWTO.html#CONFIGURE-KERNEL</a>.
</li><li class="listitem"><p class="simpara">
Redirecting non-interactive output
</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>You can redirect all non-interactive output to <span class="emphasis"><em>/dev/kmsg</em></span> and the kernel
will put it out on the console when it reaches the kernel buffer by doing</p></div><pre class="screen"># exec >/dev/kmsg 2>&1 </dev/console</pre></li></ol></div></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="using-the-dracut-shell"></a>Using the dracut shell</h4></div></div></div><p>dracut offers a shell for interactive debugging in the event dracut fails to
locate your root filesystem. To enable the shell:</p><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem">
Add the boot parameter <span class="emphasis"><em>'rd.shell</em></span>' to your bootloader configuration file
(e.g. <span class="emphasis"><em>/boot/grub2/grub.cfg</em></span>)
</li><li class="listitem"><p class="simpara">
Remove the boot arguments <span class="emphasis"><em>'rhgb</em></span>' and <span class="emphasis"><em>'quiet</em></span>'
</p><p class="simpara">A sample <span class="emphasis"><em>/boot/grub2/grub.cfg</em></span> bootloader configuration file is listed below.</p><pre class="screen">default=0
timeout=5
serial --unit=0 --speed=9600
terminal --timeout=5 serial console
title Fedora (2.6.29.5-191.fc11.x86_64)
root (hd0,0)
kernel /vmlinuz-2.6.29.5-191.fc11.x86_64 ro root=/dev/mapper/vg_uc1-lv_root console=tty0 rd.shell
initrd /dracut-2.6.29.5-191.fc11.x86_64.img</pre></li><li class="listitem"><p class="simpara">
If system boot fails, you will be dropped into a shell as seen in the example
below.
</p><pre class="screen">No root device found
Dropping to debug shell.
#</pre></li><li class="listitem">
Use this shell prompt to gather the information requested above
(see <a class="xref" href="#all-bug-reports" title="All bug reports">the section called “All bug reports”</a>).
</li></ol></div></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="accessing-the-root-volume-from-the-dracut-shell"></a>Accessing the root volume from the dracut shell</h4></div></div></div><p>From the dracut debug shell, you can manually perform the task of locating and
preparing your root volume for boot. The required steps will depend on how your
root volume is configured. Common scenarios include:</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">
A block device (e.g. <span class="emphasis"><em>/dev/sda7</em></span>)
</li><li class="listitem">
A LVM logical volume (e.g. <span class="emphasis"><em>/dev/VolGroup00/LogVol00</em></span>)
</li><li class="listitem">
An encrypted device
(e.g. <span class="emphasis"><em>/dev/mapper/luks-4d5972ea-901c-4584-bd75-1da802417d83</em></span>)
</li><li class="listitem">
A network attached device
(e.g. <span class="emphasis"><em>netroot=iscsi:@192.168.0.4::3260::iqn.2009-02.org.example:for.all</em></span>)
</li></ul></div><p>The exact method for locating and preparing will vary. However, to continue with
a successful boot, the objective is to locate your root volume and create a
symlink <span class="emphasis"><em>/dev/root</em></span> which points to the file system. For example, the following
example demonstrates accessing and booting a root volume that is an encrypted
LVM Logical volume.</p><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"><p class="simpara">
Inspect your partitions using parted
</p><pre class="screen"># parted /dev/sda -s p
Model: ATA HTS541060G9AT00 (scsi)
Disk /dev/sda: 60.0GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Number Start End Size Type File system Flags
1 32.3kB 10.8GB 107MB primary ext4 boot
2 10.8GB 55.6GB 44.7GB logical lvm</pre></li><li class="listitem"><p class="simpara">
You recall that your root volume was a LVM logical volume. Scan and activate
any logical volumes.
</p><pre class="screen"># lvm vgscan
# lvm vgchange -ay</pre></li><li class="listitem"><p class="simpara">
You should see any logical volumes now using the command blkid:
</p><pre class="screen"># blkid
/dev/sda1: UUID="3de247f3-5de4-4a44-afc5-1fe179750cf7" TYPE="ext4"
/dev/sda2: UUID="Ek4dQw-cOtq-5MJu-OGRF-xz5k-O2l8-wdDj0I" TYPE="LVM2_member"
/dev/mapper/linux-root: UUID="def0269e-424b-4752-acf3-1077bf96ad2c" TYPE="crypto_LUKS"
/dev/mapper/linux-home: UUID="c69127c1-f153-4ea2-b58e-4cbfa9257c5e" TYPE="ext3"
/dev/mapper/linux-swap: UUID="47b4d329-975c-4c08-b218-f9c9bf3635f1" TYPE="swap"</pre></li><li class="listitem"><p class="simpara">
From the output above, you recall that your root volume exists on an encrypted
block device. Following the guidance disk encryption guidance from the
Installation Guide, you unlock your encrypted root volume.
</p><pre class="screen"># UUID=$(cryptsetup luksUUID /dev/mapper/linux-root)
# cryptsetup luksOpen /dev/mapper/linux-root luks-$UUID
Enter passphrase for /dev/mapper/linux-root:
Key slot 0 unlocked.</pre></li><li class="listitem"><p class="simpara">
Next, make a symbolic link to the unlocked root volume
</p><pre class="screen"># ln -s /dev/mapper/luks-$UUID /dev/root</pre></li><li class="listitem"><p class="simpara">
With the root volume available, you may continue booting the system by exiting
the dracut shell
</p><pre class="screen"># exit</pre></li></ol></div></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="additional-dracut-boot-parameters"></a>Additional dracut boot parameters</h4></div></div></div><p>For more debugging options, see <span class="strong"><strong>dracut.cmdline</strong></span>(7).</p></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="debugging-dracut-on-shutdown"></a>Debugging dracut on shutdown</h4></div></div></div><p>To debug the shutdown sequence on systemd systems, you can <span class="emphasis"><em>rd.break</em></span>
on <span class="emphasis"><em>pre-shutdown</em></span> or <span class="emphasis"><em>shutdown</em></span>.</p><p>To do this from an already booted system:</p><pre class="screen"># mkdir -p /run/initramfs/etc/cmdline.d
# echo "rd.debug rd.break=pre-shutdown rd.break=shutdown" > /run/initramfs/etc/cmdline.d/debug.conf
# touch /run/initramfs/.need_shutdown</pre><p>This will give you a dracut shell after the system pivot’ed back in the
initramfs.</p></div></div></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="_options"></a>OPTIONS</h2></div></div></div><div class="variablelist"><dl class="variablelist"><dt><span class="term">
<span class="strong"><strong>--kver</strong></span> <span class="emphasis"><em><kernel version></em></span>
</span></dt><dd>
Set the kernel version. This enables to specify the kernel version, without
specifying the location of the initramfs image. For example:
</dd></dl></div><pre class="screen"># dracut --kver 3.5.0-0.rc7.git1.2.fc18.x86_64</pre><div class="variablelist"><dl class="variablelist"><dt><span class="term">
<span class="strong"><strong>-f, --force</strong></span>
</span></dt><dd>
Overwrite existing initramfs file.
</dd><dt><span class="term">
<span class="emphasis"><em><output file></em></span> <span class="strong"><strong>--rebuild</strong></span>
</span></dt><dd>
Append the current arguments to those with which the input initramfs image
was built. This option helps in incrementally building the initramfs for
testing. If optional <span class="emphasis"><em><output file></em></span> is not provided, the input initramfs
provided to rebuild will be used as output file.
</dd><dt><span class="term">
<span class="strong"><strong>-a, --add</strong></span> <span class="emphasis"><em><list of dracut modules></em></span>
</span></dt><dd><p class="simpara">
Add a space-separated list of dracut modules to the default set of modules.
This parameter can be specified multiple times.
</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>If the list has multiple arguments, then you have to put these in quotes. For
example:</p><pre class="screen"># dracut --add "module1 module2" ...</pre></div></dd><dt><span class="term">
<span class="strong"><strong>--force-add</strong></span> <span class="emphasis"><em><list of dracut modules></em></span>
</span></dt><dd><p class="simpara">
Force to add a space-separated list of dracut modules to the default set of
modules, when -H is specified. This parameter can be specified multiple
times.
</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>If the list has multiple arguments, then you have to put these in quotes. For
example:</p><pre class="screen"># dracut --force-add "module1 module2" ...</pre></div></dd><dt><span class="term">
<span class="strong"><strong>-o, --omit</strong></span> <span class="emphasis"><em><list of dracut modules></em></span>
</span></dt><dd><p class="simpara">
Omit a space-separated list of dracut modules. This parameter can be
specified multiple times.
</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>If the list has multiple arguments, then you have to put these in quotes. For
example:</p><pre class="screen"># dracut --omit "module1 module2" ...</pre></div></dd><dt><span class="term">
<span class="strong"><strong>-m, --modules</strong></span> <span class="emphasis"><em><list of dracut modules></em></span>
</span></dt><dd><p class="simpara">
Specify a space-separated list of dracut modules to call when building the
initramfs. Modules are located in <span class="emphasis"><em>/usr/lib/dracut/modules.d</em></span>. This
parameter can be specified multiple times.
This option forces dracut to only include the specified dracut modules.
In most cases the "--add" option is what you want to use.
</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>If the list has multiple arguments, then you have to put these in quotes. For
example:</p><pre class="screen"># dracut --modules "module1 module2" ...</pre></div></dd><dt><span class="term">
<span class="strong"><strong>-d, --drivers</strong></span> <span class="emphasis"><em><list of kernel modules></em></span>
</span></dt><dd><p class="simpara">
Specify a space-separated list of kernel modules to exclusively include
in the initramfs. The kernel modules have to be specified without the ".ko"
suffix. This parameter can be specified multiple times.
</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>If the list has multiple arguments, then you have to put these in quotes. For
example:</p><pre class="screen"># dracut --drivers "kmodule1 kmodule2" ...</pre></div></dd><dt><span class="term">
<span class="strong"><strong>--add-drivers</strong></span> <span class="emphasis"><em><list of kernel modules></em></span>
</span></dt><dd><p class="simpara">
Specify a space-separated list of kernel modules to add to the initramfs.
The kernel modules have to be specified without the ".ko" suffix. This
parameter can be specified multiple times.
</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>If the list has multiple arguments, then you have to put these in quotes. For
example:</p><pre class="screen"># dracut --add-drivers "kmodule1 kmodule2" ...</pre></div></dd><dt><span class="term">
<span class="strong"><strong>--force-drivers</strong></span> <span class="emphasis"><em><list of kernel modules></em></span>
</span></dt><dd><p class="simpara">
See add-drivers above. But in this case it is ensured that the drivers
are tried to be loaded early via modprobe.
</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>If the list has multiple arguments, then you have to put these in quotes. For
example:</p><pre class="screen"># dracut --force-drivers "kmodule1 kmodule2" ...</pre></div></dd><dt><span class="term">
<span class="strong"><strong>--omit-drivers</strong></span> <span class="emphasis"><em><list of kernel modules></em></span>
</span></dt><dd><p class="simpara">
Specify a space-separated list of kernel modules not to add to the
initramfs.
The kernel modules have to be specified without the ".ko" suffix. This
parameter can be specified multiple times.
</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>If the list has multiple arguments, then you have to put these in quotes. For
example:</p><pre class="screen"># dracut --omit-drivers "kmodule1 kmodule2" ...</pre></div></dd><dt><span class="term">
<span class="strong"><strong>--filesystems</strong></span> <span class="emphasis"><em><list of filesystems></em></span>
</span></dt><dd><p class="simpara">
Specify a space-separated list of kernel filesystem modules to exclusively
include in the generic initramfs. This parameter can be specified multiple
times.
</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>If the list has multiple arguments, then you have to put these in quotes. For
example:</p><pre class="screen"># dracut --filesystems "filesystem1 filesystem2" ...</pre></div></dd><dt><span class="term">
<span class="strong"><strong>-k, --kmoddir</strong></span> <span class="emphasis"><em><kernel directory></em></span>
</span></dt><dd>
Specify the directory, where to look for kernel modules.
</dd><dt><span class="term">
<span class="strong"><strong>--fwdir</strong></span> <span class="emphasis"><em><dir>[:<dir>…]++</em></span>
</span></dt><dd>
Specify additional directories, where to look for firmwares. This parameter
can be specified multiple times.
</dd><dt><span class="term">
<span class="strong"><strong>--libdirs</strong></span> <span class="emphasis"><em><list of directories></em></span>
</span></dt><dd><p class="simpara">
Specify a space-separated list of directories to look for libraries to
include in the generic initramfs. This parameter can be specified multiple
times.
</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>If the list has multiple arguments, then you have to put these in quotes. For
example:</p><pre class="screen"># dracut --libdirs "dir1 dir2" ...</pre></div></dd><dt><span class="term">
<span class="strong"><strong>--kernel-cmdline <parameters></strong></span>
</span></dt><dd>
Specify default kernel command line parameters.
</dd><dt><span class="term">
<span class="strong"><strong>--kernel-only</strong></span>
</span></dt><dd>
Only install kernel drivers and firmware files.
</dd><dt><span class="term">
<span class="strong"><strong>--no-kernel</strong></span>
</span></dt><dd>
Do not install kernel drivers and firmware files.
</dd><dt><span class="term">
<span class="strong"><strong>--early-microcode</strong></span>
</span></dt><dd>
Combine early microcode with ramdisk.
</dd><dt><span class="term">
<span class="strong"><strong>--no-early-microcode</strong></span>
</span></dt><dd>
Do not combine early microcode with ramdisk.
</dd><dt><span class="term">
<span class="strong"><strong>--print-cmdline</strong></span>
</span></dt><dd>
Print the kernel command line for the current disk layout.
</dd><dt><span class="term">
<span class="strong"><strong>--mdadmconf</strong></span>
</span></dt><dd>
Include local <span class="emphasis"><em>/etc/mdadm.conf</em></span> file.
</dd><dt><span class="term">
<span class="strong"><strong>--nomdadmconf</strong></span>
</span></dt><dd>
Do not include local <span class="emphasis"><em>/etc/mdadm.conf</em></span> file.
</dd><dt><span class="term">
<span class="strong"><strong>--lvmconf</strong></span>
</span></dt><dd>
Include local <span class="emphasis"><em>/etc/lvm/lvm.conf</em></span> file.
</dd><dt><span class="term">
<span class="strong"><strong>--nolvmconf</strong></span>
</span></dt><dd>
Do not include local <span class="emphasis"><em>/etc/lvm/lvm.conf</em></span> file.
</dd><dt><span class="term">
<span class="strong"><strong>--fscks</strong></span> <span class="emphasis"><em><list of fsck tools></em></span>
</span></dt><dd><p class="simpara">
Add a space-separated list of fsck tools, in addition to <span class="emphasis"><em>dracut.conf</em></span>'s
specification; the installation is opportunistic (non-existing tools are
ignored).
</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>If the list has multiple arguments, then you have to put these in quotes. For
example:</p><pre class="screen"># dracut --fscks "fsck.foo barfsck" ...</pre></div></dd><dt><span class="term">
<span class="strong"><strong>--nofscks</strong></span>
</span></dt><dd>
Inhibit installation of any fsck tools.
</dd><dt><span class="term">
<span class="strong"><strong>--strip</strong></span>
</span></dt><dd>
Strip binaries in the initramfs (default).
</dd><dt><span class="term">
<span class="strong"><strong>--aggresive-strip</strong></span>
</span></dt><dd>
Strip more than just debug symbol and sections, for a smaller initramfs
build. The --strip option must also be specified.
</dd><dt><span class="term">
<span class="strong"><strong>--nostrip</strong></span>
</span></dt><dd>
Do not strip binaries in the initramfs.
</dd><dt><span class="term">
<span class="strong"><strong>--hardlink</strong></span>
</span></dt><dd>
Hardlink files in the initramfs (default).
</dd><dt><span class="term">
<span class="strong"><strong>--nohardlink</strong></span>
</span></dt><dd>
Do not hardlink files in the initramfs.
</dd><dt><span class="term">
<span class="strong"><strong>--prefix</strong></span> <span class="emphasis"><em><dir></em></span>
</span></dt><dd>
Prefix initramfs files with the specified directory.
</dd><dt><span class="term">
<span class="strong"><strong>--noprefix</strong></span>
</span></dt><dd>
Do not prefix initramfs files (default).
</dd><dt><span class="term">
<span class="strong"><strong>-h, --help</strong></span>
</span></dt><dd>
Display help text and exit.
</dd><dt><span class="term">
<span class="strong"><strong>--debug</strong></span>
</span></dt><dd>
Output debug information of the build process.
</dd><dt><span class="term">
<span class="strong"><strong>-v, --verbose</strong></span>
</span></dt><dd>
Increase verbosity level (default is info(4)).
</dd><dt><span class="term">
<span class="strong"><strong>--version</strong></span>
</span></dt><dd>
Display version and exit.
</dd><dt><span class="term">
<span class="strong"><strong>-q, --quiet</strong></span>
</span></dt><dd>
Decrease verbosity level (default is info(4)).
</dd><dt><span class="term">
<span class="strong"><strong>-c, --conf</strong></span> <span class="emphasis"><em><dracut configuration file></em></span>
</span></dt><dd><p class="simpara">
Specify configuration file to use.
</p><p class="simpara">Default:
<span class="emphasis"><em>/etc/dracut.conf</em></span></p></dd><dt><span class="term">
<span class="strong"><strong>--confdir</strong></span> <span class="emphasis"><em><configuration directory></em></span>
</span></dt><dd><p class="simpara">
Specify configuration directory to use.
</p><p class="simpara">Default:
<span class="emphasis"><em>/etc/dracut.conf.d</em></span></p></dd><dt><span class="term">
<span class="strong"><strong>--tmpdir</strong></span> <span class="emphasis"><em><temporary directory></em></span>
</span></dt><dd><p class="simpara">
Specify temporary directory to use.
</p><p class="simpara">Default:
<span class="emphasis"><em>/var/tmp</em></span></p></dd><dt><span class="term">
<span class="strong"><strong>-r, --sysroot</strong></span> <span class="emphasis"><em><sysroot directory></em></span>
</span></dt><dd><p class="simpara">
Specify the sysroot directory to collect files from.
This is useful to create the initramfs image from
a cross-compiled sysroot directory. For the extra helper
variables, see <span class="strong"><strong>ENVIRONMENT</strong></span> below.
</p><p class="simpara">Default:
<span class="emphasis"><em>empty</em></span></p></dd><dt><span class="term">
<span class="strong"><strong>--sshkey</strong></span> <span class="emphasis"><em><sshkey file></em></span>
</span></dt><dd>
SSH key file used with ssh-client module.
</dd><dt><span class="term">
<span class="strong"><strong>--logfile</strong></span> <span class="emphasis"><em><logfile></em></span>
</span></dt><dd><p class="simpara">
Logfile to use; overrides any setting from the configuration files.
</p><p class="simpara">Default:
<span class="emphasis"><em>/var/log/dracut.log</em></span></p></dd><dt><span class="term">
<span class="strong"><strong>-l, --local</strong></span>
</span></dt><dd>
Activates the local mode. dracut will use modules from the current working
directory instead of the system-wide installed modules in
<span class="emphasis"><em>/usr/lib/dracut/modules.d</em></span>.
This is useful when running dracut from a git checkout.
</dd><dt><span class="term">
<span class="strong"><strong>-H, --hostonly</strong></span>
</span></dt><dd><p class="simpara">
Host-only mode: Install only what is needed for booting the local host
instead of a generic host and generate host-specific configuration.
</p><div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Warning</h3><p>If chrooted to another root other than the real root device, use "--fstab" and
provide a valid <span class="emphasis"><em>/etc/fstab</em></span>.</p></div></dd><dt><span class="term">
<span class="strong"><strong>-N, --no-hostonly</strong></span>
</span></dt><dd>
Disable host-only mode.
</dd><dt><span class="term">
<span class="strong"><strong>--hostonly-mode <span class="emphasis"><em><mode></em></span></strong></span>
</span></dt><dd><p class="simpara">
Specify the host-only mode to use. <span class="emphasis"><em><mode></em></span> could be one of "sloppy" or
"strict".
In "sloppy" host-only mode, extra drivers and modules will be installed, so
minor hardware change won’t make the image unbootable (e.g. changed
keyboard), and the image is still portable among similar hosts.
With "strict" mode enabled, anything not necessary for booting the local
host in its current state will not be included, and modules may do some
extra job to save more space. Minor change of hardware or environment could
make the image unbootable.
</p><p class="simpara">Default:
<span class="emphasis"><em>sloppy</em></span></p></dd><dt><span class="term">
<span class="strong"><strong>--hostonly-cmdline</strong></span>
</span></dt><dd>
Store kernel command line arguments needed in the initramfs.
</dd><dt><span class="term">
<span class="strong"><strong>--no-hostonly-cmdline</strong></span>
</span></dt><dd>
Do not store kernel command line arguments needed in the initramfs.
</dd><dt><span class="term">
<span class="strong"><strong>--no-hostonly-default-device</strong></span>
</span></dt><dd>
Do not generate implicit host devices like root, swap, fstab, etc.
Use "--mount" or "--add-device" to explicitly add devices as needed.
</dd><dt><span class="term">
<span class="strong"><strong>--hostonly-i18n</strong></span>
</span></dt><dd>
Install only needed keyboard and font files according to the host
configuration (default).
</dd><dt><span class="term">
<span class="strong"><strong>--no-hostonly-i18n</strong></span>
</span></dt><dd>
Install all keyboard and font files available.
</dd><dt><span class="term">
<span class="strong"><strong>--hostonly-nics</strong></span> <span class="emphasis"><em><list of nics></em></span>
</span></dt><dd>
Only enable listed NICs in the initramfs. The list can be empty, so other
modules can install only the necessary network drivers.
</dd><dt><span class="term">
<span class="strong"><strong>--persistent-policy</strong></span> <span class="emphasis"><em><policy></em></span>
</span></dt><dd>
Use <span class="emphasis"><em><policy></em></span> to address disks and partitions.
<span class="emphasis"><em><policy></em></span> can be any directory name found in /dev/disk.
E.g. "by-uuid", "by-label"
</dd><dt><span class="term">
<span class="strong"><strong>--fstab</strong></span>
</span></dt><dd>
Use <span class="emphasis"><em>/etc/fstab</em></span> instead of <span class="emphasis"><em>/proc/self/mountinfo</em></span>.
</dd><dt><span class="term">
<span class="strong"><strong>--add-fstab</strong></span> <span class="emphasis"><em><filename></em></span>
</span></dt><dd>
Add entries of <span class="emphasis"><em><filename></em></span> to the initramfs /etc/fstab.
</dd><dt><span class="term">
<span class="strong"><strong>--mount</strong></span> "<span class="emphasis"><em><device></em></span> <span class="emphasis"><em><mountpoint></em></span> <span class="emphasis"><em><filesystem type></em></span> [<span class="emphasis"><em><filesystem options></em></span> [<span class="emphasis"><em><dump frequency></em></span> [<span class="emphasis"><em><fsck order></em></span>]]]"
</span></dt><dd>
Mount <span class="emphasis"><em><device></em></span> on <span class="emphasis"><em><mountpoint></em></span> with <span class="emphasis"><em><filesystem type></em></span> in the
initramfs. <span class="emphasis"><em><filesystem options></em></span>, <span class="emphasis"><em><dump options></em></span> and <span class="emphasis"><em><fsck order></em></span> can
be specified, see fstab manpage for the details.
The default <span class="emphasis"><em><filesystem options></em></span> is "defaults".
The default <span class="emphasis"><em><dump frequency></em></span> is "0".
The default <span class="emphasis"><em><fsck order></em></span> is "2".
</dd><dt><span class="term">
<span class="strong"><strong>--mount</strong></span> "<span class="emphasis"><em><mountpoint></em></span>"
</span></dt><dd>
Like above, but <span class="emphasis"><em><device></em></span>, <span class="emphasis"><em><filesystem type></em></span> and <span class="emphasis"><em><filesystem options></em></span>
are determined by looking at the current mounts.
</dd><dt><span class="term">
<span class="strong"><strong>--add-device</strong></span> <span class="emphasis"><em><device></em></span>
</span></dt><dd>
Bring up <span class="emphasis"><em><device></em></span> in initramfs, <span class="emphasis"><em><device></em></span> should be the device name.
This can be useful in host-only mode for resume support when your swap is on
LVM or an encrypted partition.
[NB --device can be used for compatibility with earlier releases]
</dd><dt><span class="term">
<span class="strong"><strong>-i, --include</strong></span> <span class="emphasis"><em><SOURCE></em></span> <span class="emphasis"><em><TARGET></em></span>
</span></dt><dd>
Include the files in the SOURCE directory into the
TARGET directory in the final initramfs. If SOURCE is a file, it will be
installed to TARGET in the final initramfs. This parameter can be specified
multiple times.
</dd><dt><span class="term">
<span class="strong"><strong>-I, --install</strong></span> <span class="emphasis"><em><file list></em></span>
</span></dt><dd><p class="simpara">
Install the space separated list of files into the initramfs.
</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>If the list has multiple arguments, then you have to put these in quotes. For
example:</p><pre class="screen"># dracut --install "/bin/foo /sbin/bar" ...</pre></div></dd><dt><span class="term">
<span class="strong"><strong>--install-optional</strong></span> <span class="emphasis"><em><file list></em></span>
</span></dt><dd>
Install the space separated list of files into the initramfs, if they exist.
</dd><dt><span class="term">
<span class="strong"><strong>--gzip</strong></span>
</span></dt><dd>
Compress the generated initramfs using gzip. This will be done by default,
unless another compression option or --no-compress is passed. Equivalent to
"--compress=gzip -9".
</dd><dt><span class="term">
<span class="strong"><strong>--bzip2</strong></span>
</span></dt><dd><p class="simpara">
Compress the generated initramfs using bzip2.
</p><div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Warning</h3><p>Make sure your kernel has bzip2 decompression support compiled in, otherwise you
will not be able to boot. Equivalent to "--compress=bzip2 -9".</p></div></dd><dt><span class="term">
<span class="strong"><strong>--lzma</strong></span>
</span></dt><dd><p class="simpara">
Compress the generated initramfs using lzma.
</p><div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Warning</h3><p>Make sure your kernel has lzma decompression support compiled in, otherwise you
will not be able to boot. Equivalent to "--compress=lzma -9 -T0".</p></div></dd><dt><span class="term">
<span class="strong"><strong>--xz</strong></span>
</span></dt><dd><p class="simpara">
Compress the generated initramfs using xz.
</p><div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Warning</h3><p>Make sure your kernel has xz decompression support compiled in, otherwise you
will not be able to boot. Equivalent to
"--compress=xz --check=crc32 --lzma2=dict=1MiB -T0".</p></div></dd><dt><span class="term">
<span class="strong"><strong>--lzo</strong></span>
</span></dt><dd><p class="simpara">
Compress the generated initramfs using lzop.
</p><div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Warning</h3><p>Make sure your kernel has lzo decompression support compiled in, otherwise you
will not be able to boot. Equivalent to "--compress=lzop -9".</p></div></dd><dt><span class="term">
<span class="strong"><strong>--lz4</strong></span>
</span></dt><dd><p class="simpara">
Compress the generated initramfs using lz4.
</p><div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Warning</h3><p>Make sure your kernel has lz4 decompression support compiled in, otherwise you
will not be able to boot. Equivalent to "--compress=lz4 -l -9".</p></div></dd><dt><span class="term">
<span class="strong"><strong>--zstd</strong></span>
</span></dt><dd><p class="simpara">
Compress the generated initramfs using Zstandard.
</p><div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Warning</h3><p>Make sure your kernel has zstd decompression support compiled in, otherwise you
will not be able to boot. Equivalent to "--compress=zstd -15 -q -T0".</p></div></dd><dt><span class="term">
<span class="strong"><strong>--compress</strong></span> <span class="emphasis"><em><compressor></em></span>
</span></dt><dd>
Compress the generated initramfs using the passed compression program. If
you pass it just the name of a compression program, it will call that
program with known-working arguments. If you pass a quoted string with
arguments, it will be called with exactly those arguments. Depending on what
you pass, this may result in an initramfs that the kernel cannot decompress.
The default value can also be set via the <span class="emphasis"><em>INITRD_COMPRESS</em></span> environment
variable.
</dd><dt><span class="term">
<span class="strong"><strong>--squash-compressor</strong></span> <span class="emphasis"><em><compressor></em></span>
</span></dt><dd>
Compress the squashfs image using the passed compressor and compressor
specific options for mksquashfs. You can refer to mksquashfs manual for
supported compressors and compressor specific options. If squash module is
not called when building the initramfs, this option will not take effect.
</dd><dt><span class="term">
<span class="strong"><strong>--no-compress</strong></span>
</span></dt><dd>
Do not compress the generated initramfs. This will override any other
compression options.
</dd><dt><span class="term">
<span class="strong"><strong>--reproducible</strong></span>
</span></dt><dd>
Create reproducible images.
</dd><dt><span class="term">
<span class="strong"><strong>--no-reproducible</strong></span>
</span></dt><dd>
Do not create reproducible images.
</dd><dt><span class="term">
<span class="strong"><strong>--list-modules</strong></span>
</span></dt><dd>
List all available dracut modules.
</dd><dt><span class="term">
<span class="strong"><strong>-M, --show-modules</strong></span>
</span></dt><dd>
Print included module’s name to standard output during build.
</dd><dt><span class="term">
<span class="strong"><strong>--keep</strong></span>
</span></dt><dd>
Keep the initramfs temporary directory for debugging purposes.
</dd><dt><span class="term">
<span class="strong"><strong>--printsize</strong></span>
</span></dt><dd>
Print out the module install size.
</dd><dt><span class="term">
<span class="strong"><strong>--profile</strong></span>
</span></dt><dd>
Output profile information of the build process.
</dd><dt><span class="term">
<span class="strong"><strong>--ro-mnt</strong></span>
</span></dt><dd>
Mount / and /usr read-only by default.
</dd><dt><span class="term">
<span class="strong"><strong>-L, --stdlog</strong></span> <span class="emphasis"><em><level></em></span>
</span></dt><dd>
[0-6] Specify logging level (to standard error).
</dd></dl></div><pre class="screen"> 0 - suppress any messages
1 - only fatal errors
2 - all errors
3 - warnings
4 - info
5 - debug info (here starts lots of output)
6 - trace info (and even more)</pre><div class="variablelist"><dl class="variablelist"><dt><span class="term">
<span class="strong"><strong>--regenerate-all</strong></span>
</span></dt><dd>
Regenerate all initramfs images at the default location with the kernel
versions found on the system. Additional parameters are passed through.
</dd><dt><span class="term">
<span class="strong"><strong>-p, --parallel</strong></span>
</span></dt><dd>
Try to execute tasks in parallel. Currently only supported with
<span class="strong"><strong>--regenerate-all</strong></span> (build initramfs images for all kernel
versions simultaneously).
</dd><dt><span class="term">
<span class="strong"><strong>--noimageifnotneeded</strong></span>
</span></dt><dd>
Do not create an image in host-only mode, if no kernel driver is needed
and no /etc/cmdline/*.conf will be generated into the initramfs.
</dd><dt><span class="term">
<span class="strong"><strong>--loginstall <span class="emphasis"><em><directory></em></span></strong></span>
</span></dt><dd>
Log all files installed from the host to <span class="emphasis"><em><directory></em></span>.
</dd><dt><span class="term">
<span class="strong"><strong>--uefi</strong></span>
</span></dt><dd>
Instead of creating an initramfs image, dracut will create an UEFI
executable, which can be executed by an UEFI BIOS. The default output
filename is <span class="emphasis"><em><EFI>/EFI/Linux/linux-$kernel$-<MACHINE_ID>-<BUILD_ID>.efi</em></span>.
<EFI> might be <span class="emphasis"><em>/efi</em></span>, <span class="emphasis"><em>/boot</em></span> or <span class="emphasis"><em>/boot/efi</em></span> depending on where the ESP
partition is mounted. The <BUILD_ID> is taken from BUILD_ID in
<span class="emphasis"><em>/usr/lib/os-release</em></span> or if it exists <span class="emphasis"><em>/etc/os-release</em></span> and is left out,
if BUILD_ID is non-existant or empty.
</dd><dt><span class="term">
<span class="strong"><strong>--no-uefi</strong></span>
</span></dt><dd>
Disables UEFI mode.
</dd><dt><span class="term">
<span class="strong"><strong>--no-machineid</strong></span>
</span></dt><dd>
Affects the default output filename of <span class="strong"><strong>--uefi</strong></span> and will discard the
<MACHINE_ID> part.
</dd><dt><span class="term">
<span class="strong"><strong>--uefi-stub <span class="emphasis"><em><file></em></span></strong></span>
</span></dt><dd>
Specifies the UEFI stub loader, which will load the attached kernel,
initramfs and kernel command line and boots the kernel. The default is
<span class="emphasis"><em>$prefix/lib/systemd/boot/efi/linux<EFI-MACHINE-TYPE-NAME>.efi.stub</em></span>.
</dd><dt><span class="term">
<span class="strong"><strong>--uefi-splash-image <span class="emphasis"><em><file></em></span></strong></span>
</span></dt><dd>
Specifies the UEFI stub loader’s splash image. Requires bitmap (<span class="strong"><strong>.bmp</strong></span>)
image format.
</dd><dt><span class="term">
<span class="strong"><strong>--kernel-image <span class="emphasis"><em><file></em></span></strong></span>
</span></dt><dd>
Specifies the kernel image, which to include in the UEFI executable. The
default is <span class="emphasis"><em>/lib/modules/<KERNEL-VERSION>/vmlinuz</em></span> or
<span class="emphasis"><em>/boot/vmlinuz-<KERNEL-VERSION></em></span>.
</dd><dt><span class="term">
<span class="strong"><strong>--sbat <parameters></strong></span>
</span></dt><dd>
Specifies the SBAT parameters, which to include in the UEFI executable. By default
the default SBAT string added is "sbat,1,SBAT Version,sbat,1,
<a class="ulink" href="https://github.com/rhboot/shim/blob/main/SBAT.md" target="_top">https://github.com/rhboot/shim/blob/main/SBAT.md</a>".
</dd><dt><span class="term">
<span class="strong"><strong>--enhanced-cpio</strong></span>
</span></dt><dd>
Attempt to use the dracut-cpio binary, which optimizes archive creation for
copy-on-write filesystems by using the copy_file_range(2) syscall via Rust’s
io::copy(). When specified, initramfs archives are also padded to ensure
optimal data alignment for extent sharing. To retain reflink data
deduplication benefits, this should be used alongside the <span class="strong"><strong>--no-compress</strong></span>
and <span class="strong"><strong>--no-strip</strong></span> parameters, with initramfs source files, <span class="strong"><strong>--tmpdir</strong></span>
staging area and destination all on the same copy-on-write capable
filesystem.
</dd></dl></div></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="_environment"></a>ENVIRONMENT</h2></div></div></div><div class="variablelist"><dl class="variablelist"><dt><span class="term">
<span class="emphasis"><em>INITRD_COMPRESS</em></span>
</span></dt><dd>
sets the default compression program. See <span class="strong"><strong>--compress</strong></span>.
</dd><dt><span class="term">
<span class="emphasis"><em>DRACUT_LDCONFIG</em></span>
</span></dt><dd><p class="simpara">
sets the <span class="emphasis"><em>ldconfig</em></span> program path and options. Optional.
Used for <span class="strong"><strong>--sysroot</strong></span>.
</p><p class="simpara">Default:
<span class="emphasis"><em>ldconfig</em></span></p></dd><dt><span class="term">
<span class="emphasis"><em>DRACUT_LDD</em></span>
</span></dt><dd><p class="simpara">
sets the <span class="emphasis"><em>ldd</em></span> program path and options. Optional.
Used for <span class="strong"><strong>--sysroot</strong></span>.
</p><p class="simpara">Default:
<span class="emphasis"><em>ldd</em></span></p></dd><dt><span class="term">
<span class="emphasis"><em>DRACUT_TESTBIN</em></span>
</span></dt><dd><p class="simpara">
sets the initially tested binary for detecting library paths.
Optional. Used for <span class="strong"><strong>--sysroot</strong></span>. In the cross-compiled sysroot,
the default value (<span class="emphasis"><em>/bin/sh</em></span>) is unusable, as it is an absolute
symlink and points outside the sysroot directory.
</p><p class="simpara">Default:
<span class="emphasis"><em>/bin/sh</em></span></p></dd><dt><span class="term">
<span class="emphasis"><em>DRACUT_INSTALL</em></span>
</span></dt><dd><p class="simpara">
overrides path and options for executing <span class="emphasis"><em>dracut-install</em></span> internally.
Optional. Can be used to debug <span class="emphasis"><em>dracut-install</em></span> while running the
main dracut script.
</p><p class="simpara">Default:
<span class="emphasis"><em>dracut-install</em></span></p><p class="simpara">Example:
DRACUT_INSTALL="valgrind dracut-install"</p></dd><dt><span class="term">
<span class="emphasis"><em>DRACUT_COMPRESS_BZIP2</em></span>
, </span><span class="term">
<span class="emphasis"><em>DRACUT_COMPRESS_BZIP2</em></span>
, </span><span class="term">
<span class="emphasis"><em>DRACUT_COMPRESS_LBZIP2</em></span>
, </span><span class="term">
<span class="emphasis"><em>DRACUT_COMPRESS_LZMA</em></span>
, </span><span class="term">
<span class="emphasis"><em>DRACUT_COMPRESS_XZ</em></span>
, </span><span class="term">
<span class="emphasis"><em>DRACUT_COMPRESS_GZIP</em></span>
, </span><span class="term">
<span class="emphasis"><em>DRACUT_COMPRESS_PIGZ</em></span>
, </span><span class="term">
<span class="emphasis"><em>DRACUT_COMPRESS_LZOP</em></span>
, </span><span class="term">
<span class="emphasis"><em>DRACUT_COMPRESS_ZSTD</em></span>
, </span><span class="term">
<span class="emphasis"><em>DRACUT_COMPRESS_LZ4</em></span>
, </span><span class="term">
<span class="emphasis"><em>DRACUT_COMPRESS_CAT</em></span>
</span></dt><dd><p class="simpara">
overrides for compression utilities to support using them from
non-standard paths.
</p><p class="simpara">Default values are the default compression utility names to be found in <span class="strong"><strong>PATH</strong></span>.</p></dd><dt><span class="term">
<span class="emphasis"><em>DRACUT_ARCH</em></span>
</span></dt><dd><p class="simpara">
overrides the value of <span class="strong"><strong>uname -m</strong></span>. Used for <span class="strong"><strong>--sysroot</strong></span>.
</p><p class="simpara">Default:
<span class="emphasis"><em>empty</em></span> (the value of <span class="strong"><strong>uname -m</strong></span> on the host system)</p></dd><dt><span class="term">
<span class="emphasis"><em>SYSTEMD_VERSION</em></span>
</span></dt><dd>
overrides systemd version. Used for <span class="strong"><strong>--sysroot</strong></span>.
</dd><dt><span class="term">
<span class="emphasis"><em>SYSTEMCTL</em></span>
</span></dt><dd>
overrides the systemctl binary. Used for <span class="strong"><strong>--sysroot</strong></span>.
</dd><dt><span class="term">
<span class="emphasis"><em>NM_VERSION</em></span>
</span></dt><dd>
overrides the NetworkManager version. Used for <span class="strong"><strong>--sysroot</strong></span>.
</dd><dt><span class="term">
<span class="emphasis"><em>DRACUT_INSTALL_PATH</em></span>
</span></dt><dd><p class="simpara">
overrides <span class="strong"><strong>PATH</strong></span> environment for <span class="strong"><strong>dracut-install</strong></span> to look for
binaries relative to <span class="strong"><strong>--sysroot</strong></span>. In a cross-compiled environment
(e.g. Yocto), PATH points to natively built binaries that are not
in the host’s /bin, /usr/bin, etc. <span class="strong"><strong>dracut-install</strong></span> still needs plain
/bin and /usr/bin that are relative to the cross-compiled sysroot.
</p><p class="simpara">Default:
<span class="emphasis"><em>PATH</em></span></p></dd><dt><span class="term">
<span class="emphasis"><em>DRACUT_INSTALL_LOG_TARGET</em></span>
</span></dt><dd><p class="simpara">
overrides <span class="strong"><strong>DRACUT_LOG_TARGET</strong></span> for <span class="strong"><strong>dracut-install</strong></span>. It allows
running <span class="strong"><strong>dracut-install* to run with different log target that
</strong></span>dracut** runs with.
</p><p class="simpara">Default:
<span class="emphasis"><em>DRACUT_LOG_TARGET</em></span></p></dd><dt><span class="term">
<span class="emphasis"><em>DRACUT_INSTALL_LOG_LEVEL</em></span>
</span></dt><dd><p class="simpara">
overrides <span class="strong"><strong>DRACUT_LOG_LEVEL</strong></span> for <span class="strong"><strong>dracut-install</strong></span>. It allows
running <span class="strong"><strong>dracut-install* to run with different log level that
</strong></span>dracut** runs with.
</p><p class="simpara">Default:
<span class="emphasis"><em>DRACUT_LOG_LEVEL</em></span></p></dd></dl></div></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="_files"></a>FILES</h2></div></div></div><div class="variablelist"><dl class="variablelist"><dt><span class="term">
<span class="emphasis"><em>/var/log/dracut.log</em></span>
</span></dt><dd>
logfile of initramfs image creation
</dd><dt><span class="term">
<span class="emphasis"><em>/tmp/dracut.log</em></span>
</span></dt><dd>
logfile of initramfs image creation, if <span class="emphasis"><em>/var/log/dracut.log</em></span> is not
writable
</dd><dt><span class="term">
<span class="emphasis"><em>/etc/dracut.conf</em></span>
</span></dt><dd>
see dracut.conf5
</dd><dt><span class="term">
<span class="emphasis"><em>/etc/dracut.conf.d/*.conf</em></span>
</span></dt><dd>
see dracut.conf5
</dd><dt><span class="term">
<span class="emphasis"><em>/usr/lib/dracut/dracut.conf.d/*.conf</em></span>
</span></dt><dd>
see dracut.conf5
</dd></dl></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_configuration_in_the_initramfs"></a>Configuration in the initramfs</h3></div></div></div><div class="variablelist"><dl class="variablelist"><dt><span class="term">
<span class="emphasis"><em>/etc/conf.d/</em></span>
</span></dt><dd>
Any files found in <span class="emphasis"><em>/etc/conf.d/</em></span> will be sourced in the initramfs to
set initial values. Command line options will override these values
set in the configuration files.
</dd><dt><span class="term">
<span class="emphasis"><em>/etc/cmdline</em></span>
</span></dt><dd>
Can contain additional command line options. Deprecated, better use
/etc/cmdline.d/*.conf.
</dd><dt><span class="term">
<span class="emphasis"><em>/etc/cmdline.d/*.conf</em></span>
</span></dt><dd>
Can contain additional command line options.
</dd></dl></div></div></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="_availability"></a>AVAILABILITY</h2></div></div></div><p>The dracut command is part of the dracut package and is available from
<a class="ulink" href="https://dracut.wiki.kernel.org" target="_top">https://dracut.wiki.kernel.org</a></p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="_authors"></a>AUTHORS</h2></div></div></div><p>Harald Hoyer</p><p>Victor Lowther</p><p>Amadeusz Żołnowski</p><p>Hannes Reinecke</p><p>Daniel Molkentin</p><p>Will Woods</p><p>Philippe Seewer</p><p>Warren Togami</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="_see_also"></a>SEE ALSO</h2></div></div></div><p><span class="strong"><strong>dracut.cmdline</strong></span>(7) <span class="strong"><strong>dracut.conf</strong></span>(5) <span class="strong"><strong>lsinitrd</strong></span>(1)</p></div></div><div class="chapter"><div class="titlepage"><div><div><h2 class="title"><a id="dracutconf5"></a>Chapter 7. DRACUT.CONF(5)</h2></div></div></div><div class="toc"><p><strong>Table of Contents</strong></p><dl class="toc"><dt><span class="section"><a href="#_name_2">NAME</a></span></dt><dt><span class="section"><a href="#_synopsis_2">SYNOPSIS</a></span></dt><dt><span class="section"><a href="#_description_2">Description</a></span></dt><dt><span class="section"><a href="#_files_2">Files</a></span></dt><dt><span class="section"><a href="#_author">AUTHOR</a></span></dt><dt><span class="section"><a href="#_see_also_2">See Also</a></span></dt></dl></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="_name_2"></a>NAME</h2></div></div></div><p>dracut.conf - configuration file(s) for dracut</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="_synopsis_2"></a>SYNOPSIS</h2></div></div></div><p><span class="emphasis"><em>/etc/dracut.conf</em></span>
<span class="emphasis"><em>/etc/dracut.conf.d/*.conf</em></span>
<span class="emphasis"><em>/usr/lib/dracut/dracut.conf.d/*.conf</em></span></p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="_description_2"></a>Description</h2></div></div></div><p><span class="emphasis"><em>dracut.conf</em></span> is loaded during the initialisation phase of dracut. Command line
parameter will override any values set here.</p><p><span class="emphasis"><em>*.conf</em></span> files are read from /usr/lib/dracut/dracut.conf.d and
/etc/dracut.conf.d. Files with the same name in /etc/dracut.conf.d will replace
files in /usr/lib/dracut/dracut.conf.d.
The files are then read in alphanumerical order and will override parameters
set in <span class="emphasis"><em>/etc/dracut.conf</em></span>. Each line specifies an attribute and a value. A <span class="emphasis"><em>#</em></span>
indicates the beginning of a comment; following characters, up to the end of the
line are not interpreted.</p><p>dracut command line options will override any values set here.</p><p>Configuration files must have the extension .conf; other extensions are ignored.</p><div class="variablelist"><dl class="variablelist"><dt><span class="term">
<span class="strong"><strong>add_dracutmodules+=</strong></span>" <span class="emphasis"><em><dracut modules></em></span> "
</span></dt><dd>
Add a space-separated list of dracut modules to call when building the
initramfs. Modules are located in <span class="emphasis"><em>/usr/lib/dracut/modules.d</em></span>.
</dd><dt><span class="term">
<span class="strong"><strong>force_add_dracutmodules+=</strong></span>" <span class="emphasis"><em><dracut modules></em></span> "
</span></dt><dd>
Force to add a space-separated list of dracut modules to the default set of
modules, when host-only mode is specified. This parameter can be specified
multiple times.
</dd><dt><span class="term">
<span class="strong"><strong>omit_dracutmodules+=</strong></span>" <span class="emphasis"><em><dracut modules></em></span> "
</span></dt><dd>
Omit a space-separated list of dracut modules to call when building the
initramfs. Modules are located in <span class="emphasis"><em>/usr/lib/dracut/modules.d</em></span>.
</dd><dt><span class="term">
<span class="strong"><strong>dracutmodules+=</strong></span>" <span class="emphasis"><em><dracut modules></em></span> "
</span></dt><dd>
Specify a space-separated list of dracut modules to call when building the
initramfs. Modules are located in <span class="emphasis"><em>/usr/lib/dracut/modules.d</em></span>.
This option forces dracut to only include the specified dracut modules.
In most cases the "add_dracutmodules" option is what you want to use.
</dd><dt><span class="term">
<span class="strong"><strong>add_drivers+=</strong></span>" <span class="emphasis"><em><kernel modules></em></span> "
</span></dt><dd>
Specify a space-separated list of kernel modules to add to the initramfs.
The kernel modules have to be specified without the ".ko" suffix.
</dd><dt><span class="term">
<span class="strong"><strong>force_drivers+=</strong></span>" <span class="emphasis"><em><list of kernel modules></em></span> "
</span></dt><dd>
See add_drivers above. But in this case it is ensured that the drivers
are tried to be loaded early via modprobe.
</dd><dt><span class="term">
<span class="strong"><strong>omit_drivers+=</strong></span>" <span class="emphasis"><em><kernel modules></em></span> "
</span></dt><dd>
Specify a space-separated list of kernel modules not to add to the
initramfs. The kernel modules have to be specified without the ".ko" suffix.
</dd><dt><span class="term">
<span class="strong"><strong>drivers+=</strong></span>" <span class="emphasis"><em><kernel modules></em></span> "
</span></dt><dd>
Specify a space-separated list of kernel modules to exclusively include in
the initramfs. The kernel modules have to be specified without the ".ko"
suffix.
</dd><dt><span class="term">
<span class="strong"><strong>filesystems+=</strong></span>" <span class="emphasis"><em><filesystem names></em></span> "
</span></dt><dd>
Specify a space-separated list of kernel filesystem modules to exclusively
include in the generic initramfs.
</dd><dt><span class="term">
<span class="strong"><strong>drivers_dir=</strong></span>"<span class="emphasis"><em><kernel modules directory></em></span>"
</span></dt><dd>
Specify the directory where to look for kernel modules.
</dd><dt><span class="term">
<span class="strong"><strong>fw_dir+=</strong></span>" :<span class="emphasis"><em><dir></em></span>[:<span class="emphasis"><em><dir></em></span> …] "
</span></dt><dd>
Specify additional colon-separated list of directories where to look for
firmware files.
</dd><dt><span class="term">
<span class="strong"><strong>libdirs+=</strong></span>" <span class="emphasis"><em><dir></em></span>[ <span class="emphasis"><em><dir></em></span> …] "
</span></dt><dd>
Specify a space-separated list of directories where to look for libraries.
</dd><dt><span class="term">
<span class="strong"><strong>install_items+=</strong></span>" <span class="emphasis"><em><file></em></span>[ <span class="emphasis"><em><file></em></span> …] "
</span></dt><dd>
Specify additional files to include in the initramfs, separated by spaces.
</dd><dt><span class="term">
<span class="strong"><strong>install_optional_items+=</strong></span>" <span class="emphasis"><em><file></em></span>[ <span class="emphasis"><em><file></em></span> …] "
</span></dt><dd>
Specify additional files to include in the initramfs, separated by spaces,
if they exist.
</dd><dt><span class="term">
<span class="strong"><strong>compress=</strong></span>"<span class="emphasis"><em>{cat|bzip2|lzma|xz|gzip|lzo|lz4|zstd|<compressor [args …]>}</em></span>"
</span></dt><dd>
Compress the generated initramfs using the passed compression program. If
you pass it just the name of a compression program, it will call that
program with known-working arguments. If you pass arguments, it will be
called with exactly those arguments. Depending on what you pass, this may
result in an initramfs that the kernel cannot decompress.
To disable compression, use "cat".
</dd><dt><span class="term">
<span class="strong"><strong>squash_compress=</strong></span>"<span class="emphasis"><em>{<compressor [args …]>}</em></span>"
</span></dt><dd>
Compress the squashfs image using the passed compressor and compressor
specific options for mksquashfs. You can refer to mksquashfs manual for
supported compressors and compressor specific options. If squash module is
not called when building the initramfs, this option will not take effect.
</dd><dt><span class="term">
<span class="strong"><strong>do_strip=</strong></span>"<span class="emphasis"><em>{yes|no}</em></span>"
</span></dt><dd>
Strip binaries in the initramfs (default=yes).
</dd><dt><span class="term">
<span class="strong"><strong>aggresive_strip=</strong></span>"<span class="emphasis"><em>{yes|no}</em></span>"
</span></dt><dd>
Strip more than just debug symbol and sections, for a smaller initramfs
build. The "do_strip=yes" option must also be specified (default=no).
</dd><dt><span class="term">
<span class="strong"><strong>do_hardlink=</strong></span>"<span class="emphasis"><em>{yes|no}</em></span>"
</span></dt><dd>
Hardlink files in the initramfs (default=yes).
</dd><dt><span class="term">
<span class="strong"><strong>prefix=</strong></span>" <span class="emphasis"><em><directory></em></span> "
</span></dt><dd>
Prefix initramfs files with <span class="emphasis"><em><directory></em></span>.
</dd><dt><span class="term">
<span class="strong"><strong>hostonly=</strong></span>"<span class="emphasis"><em>{yes|no}</em></span>"
</span></dt><dd>
Host-only mode: Install only what is needed for booting the local host
instead of a generic host and generate host-specific configuration
(default=no).
</dd><dt><span class="term">
<span class="strong"><strong>hostonly_mode=</strong></span>"<span class="emphasis"><em>{sloppy|strict}</em></span>"
</span></dt><dd>
Specify the host-only mode to use (default=sloppy).
In "sloppy" host-only mode, extra drivers and modules will be installed, so
minor hardware change won’t make the image unbootable (e.g. changed
keyboard), and the image is still portable among similar hosts.
With "strict" mode enabled, anything not necessary for booting the local
host in its current state will not be included, and modules may do some
extra job to save more space. Minor change of hardware or environment could
make the image unbootable.
</dd><dt><span class="term">
<span class="strong"><strong>hostonly_cmdline=</strong></span>"<span class="emphasis"><em>{yes|no}</em></span>"
</span></dt><dd>
If set to "yes", store the kernel command line arguments needed in the
initramfs. If <span class="strong"><strong>hostonly="yes"</strong></span> and this option is not configured, it’s
automatically set to "yes".
</dd><dt><span class="term">
<span class="strong"><strong>hostonly_nics+=</strong></span>" [<span class="emphasis"><em><nic></em></span>[ <span class="emphasis"><em><nic></em></span> …]] "
</span></dt><dd>
Only enable listed NICs in the initramfs. The list can be empty, so other
modules can install only the necessary network drivers.
</dd><dt><span class="term">
<span class="strong"><strong>persistent_policy=</strong></span>"<span class="emphasis"><em><policy></em></span>"
</span></dt><dd>
Use <span class="emphasis"><em><policy></em></span> to address disks and partitions.
<span class="emphasis"><em><policy></em></span> can be any directory name found in /dev/disk.
E.g. "by-uuid", "by-label"
</dd><dt><span class="term">
<span class="strong"><strong>tmpdir=</strong></span>"<span class="emphasis"><em><temporary directory></em></span>"
</span></dt><dd>
Specify temporary directory to use.
</dd></dl></div><div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Warning</h3><p>If chrooted to another root other than the real root device, use --fstab and
provide a valid <span class="emphasis"><em>/etc/fstab</em></span>.</p></div><div class="variablelist"><dl class="variablelist"><dt><span class="term">
<span class="strong"><strong>use_fstab=</strong></span>"<span class="emphasis"><em>{yes|no}</em></span>"
</span></dt><dd>
Use <span class="emphasis"><em>/etc/fstab</em></span> instead of <span class="emphasis"><em>/proc/self/mountinfo</em></span> (default=no).
</dd><dt><span class="term">
<span class="strong"><strong>add_fstab+=</strong></span>" <span class="emphasis"><em><filename></em></span> "
</span></dt><dd>
Add entries of <span class="emphasis"><em><filename></em></span> to the initramfs /etc/fstab.
</dd><dt><span class="term">
<span class="strong"><strong>add_device+=</strong></span>" <span class="emphasis"><em><device></em></span> "
</span></dt><dd>
Bring up <span class="emphasis"><em><device></em></span> in initramfs, <span class="emphasis"><em><device></em></span> should be the device name.
This can be useful in host-only mode for resume support when your swap is on
LVM an encrypted partition.
</dd><dt><span class="term">
<span class="strong"><strong>mdadmconf=</strong></span>"<span class="emphasis"><em>{yes|no}</em></span>"
</span></dt><dd>
Include local <span class="emphasis"><em>/etc/mdadm.conf</em></span> (default=no).
</dd><dt><span class="term">
<span class="strong"><strong>lvmconf=</strong></span>"<span class="emphasis"><em>{yes|no}</em></span>"
</span></dt><dd>
Include local <span class="emphasis"><em>/etc/lvm/lvm.conf</em></span> (default=no).
</dd><dt><span class="term">
<span class="strong"><strong>fscks=</strong></span>" <span class="emphasis"><em><fsck tools></em></span> "
</span></dt><dd>
Add a space-separated list of fsck tools. If nothing is specified, the
default is: "umount mount /sbin/fsck* xfs_db xfs_check xfs_repair e2fsck
jfs_fsck reiserfsck btrfsck". The installation is opportunistic
(non-existing tools are ignored).
</dd><dt><span class="term">
<span class="strong"><strong>nofscks=</strong></span>"<span class="emphasis"><em>{yes|no}</em></span>"
</span></dt><dd>
If specified, inhibit installation of any fsck tools (default=no).
</dd><dt><span class="term">
<span class="strong"><strong>ro_mnt=</strong></span>"<span class="emphasis"><em>{yes|no}</em></span>"
</span></dt><dd>
Mount <span class="emphasis"><em>/</em></span> and <span class="emphasis"><em>/usr</em></span> read-only by default (default=no).
</dd><dt><span class="term">
<span class="strong"><strong>kernel_cmdline=</strong></span>"<span class="emphasis"><em>parameters</em></span>"
</span></dt><dd>
Specify default kernel command line parameters.
</dd><dt><span class="term">
<span class="strong"><strong>kernel_only=</strong></span>"<span class="emphasis"><em>{yes|no}</em></span>"
</span></dt><dd>
Only install kernel drivers and firmware files (default=no).
</dd><dt><span class="term">
<span class="strong"><strong>no_kernel=</strong></span>"<span class="emphasis"><em>{yes|no}</em></span>"
</span></dt><dd>
Do not install kernel drivers and firmware files (default=no).
</dd><dt><span class="term">
<span class="strong"><strong>acpi_override=</strong></span>"<span class="emphasis"><em>{yes|no}</em></span>"
</span></dt><dd>
[WARNING] ONLY USE THIS IF YOU KNOW WHAT YOU ARE DOING!
Override BIOS provided ACPI tables. For further documentation read
Documentation/acpi/initrd_table_override.txt in the kernel sources.
Search for ACPI table files (must have .aml suffix) in acpi_table_dir=
directory (see below) and add them to a separate uncompressed cpio
archive. This cpio archive gets glued (concatenated, uncompressed one
must be the first one) to the compressed cpio archive. The first,
uncompressed cpio archive is for data which the kernel must be able
to access very early (and cannot make use of uncompress algorithms yet)
like microcode or ACPI tables (default=no).
</dd><dt><span class="term">
<span class="strong"><strong>acpi_table_dir=</strong></span>"<span class="emphasis"><em><dir></em></span>"
</span></dt><dd>
Directory to search for ACPI tables if acpi_override= is set to yes.
</dd><dt><span class="term">
<span class="strong"><strong>early_microcode=</strong></span>"{yes|no}"
</span></dt><dd>
Combine early microcode with ramdisk (default=yes).
</dd><dt><span class="term">
<span class="strong"><strong>stdloglvl</strong></span>="<span class="emphasis"><em>{0-6}</em></span>"
</span></dt><dd>
Specify logging level for standard error (default=4).
</dd></dl></div><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>Logging levels:</p><pre class="screen"> 0 - suppress any messages
1 - only fatal errors
2 - all errors
3 - warnings
4 - info
5 - debug info (here starts lots of output)
6 - trace info (and even more)</pre></div><div class="variablelist"><dl class="variablelist"><dt><span class="term">
<span class="strong"><strong>sysloglvl</strong></span>="<span class="emphasis"><em>{0-6}</em></span>"
</span></dt><dd>
Specify logging level for syslog (default=0).
</dd><dt><span class="term">
<span class="strong"><strong>fileloglvl=</strong></span>"<span class="emphasis"><em>{0-6}</em></span>"
</span></dt><dd>
Specify logging level for logfile (default=4).
</dd><dt><span class="term">
<span class="strong"><strong>logfile=</strong></span>"<span class="emphasis"><em><file></em></span>"
</span></dt><dd>
Path to logfile.
</dd><dt><span class="term">
<span class="strong"><strong>sshkey=</strong></span>"<span class="emphasis"><em><file></em></span>"
</span></dt><dd>
SSH key file used with ssh-client module.
</dd><dt><span class="term">
<span class="strong"><strong>show_modules=</strong></span>"<span class="emphasis"><em>{yes|no}</em></span>"
</span></dt><dd>
Print the name of the included modules to standard output during build
(default=no).
</dd><dt><span class="term">
<span class="strong"><strong>i18n_vars=</strong></span>"<span class="emphasis"><em><variable mapping></em></span>"
</span></dt><dd>
Distribution specific variable mapping.
See dracut/modules.d/10i18n/README for a detailed description.
</dd><dt><span class="term">
<span class="strong"><strong>i18n_default_font=</strong></span>"<span class="emphasis"><em><fontname></em></span>"
</span></dt><dd>
The font <fontname> to install, if not specified otherwise.
Default is "eurlatgr".
</dd><dt><span class="term">
<span class="strong"><strong>i18n_install_all=</strong></span>"<span class="emphasis"><em>{yes|no}</em></span>"
</span></dt><dd>
Install everything regardless of generic or host-only mode (default=no).
</dd><dt><span class="term">
<span class="strong"><strong>reproducible=</strong></span>"<span class="emphasis"><em>{yes|no}</em></span>"
</span></dt><dd>
Create reproducible images (default=no).
</dd><dt><span class="term">
<span class="strong"><strong>noimageifnotneeded=</strong></span>"<span class="emphasis"><em>{yes|no}</em></span>"
</span></dt><dd>
Do not create an image in host-only mode, if no kernel driver is needed
and no /etc/cmdline/*.conf will be generated into the initramfs
(default=no).
</dd><dt><span class="term">
<span class="strong"><strong>loginstall=</strong></span>"<span class="emphasis"><em><directory></em></span>"
</span></dt><dd>
Log all files installed from the host to <span class="emphasis"><em><directory></em></span>.
</dd><dt><span class="term">
<span class="strong"><strong>uefi=</strong></span>"<span class="emphasis"><em>{yes|no}</em></span>"
</span></dt><dd>
Instead of creating an initramfs image, dracut will create an UEFI
executable, which can be executed by an UEFI BIOS (default=no).
The default output filename is
<span class="emphasis"><em><EFI>/EFI/Linux/linux-$kernel$-<MACHINE_ID>-<BUILD_ID>.efi</em></span>.
<EFI> might be <span class="emphasis"><em>/efi</em></span>, <span class="emphasis"><em>/boot</em></span> or <span class="emphasis"><em>/boot/efi</em></span> depending on where the ESP
partition is mounted. The <BUILD_ID> is taken from BUILD_ID in
<span class="emphasis"><em>/usr/lib/os-release</em></span> or if it exists <span class="emphasis"><em>/etc/os-release</em></span> and is left out,
if BUILD_ID is non-existant or empty.
</dd><dt><span class="term">
<span class="strong"><strong>machine_id=</strong></span>"<span class="emphasis"><em>{yes|no}</em></span>"
</span></dt><dd>
Affects the default output filename of the UEFI executable, including the
<MACHINE_ID> part (default=yes).
</dd><dt><span class="term">
<span class="strong"><strong>uefi_stub=</strong></span>"<span class="emphasis"><em><file></em></span>"
</span></dt><dd>
Specifies the UEFI stub loader, which will load the attached kernel,
initramfs and kernel command line and boots the kernel. The default is
<span class="emphasis"><em>/lib/systemd/boot/efi/linux<EFI-MACHINE-TYPE-NAME>.efi.stub</em></span>.
</dd><dt><span class="term">
<span class="strong"><strong>uefi_splash_image=</strong></span>"<span class="emphasis"><em><file></em></span>"
</span></dt><dd>
Specifies the UEFI stub loader’s splash image. Requires bitmap (<span class="strong"><strong>.bmp</strong></span>)
image format.
</dd><dt><span class="term">
<span class="strong"><strong>uefi_secureboot_cert=</strong></span>"<span class="emphasis"><em><file></em></span>", <span class="strong"><strong>uefi_secureboot_key=</strong></span>"<span class="emphasis"><em><file></em></span>"
</span></dt><dd>
Specifies a certificate and corresponding key, which are used to sign the
created UEFI executable.
Requires both certificate and key need to be specified and <span class="emphasis"><em>sbsign</em></span> to be
installed.
</dd><dt><span class="term">
<span class="strong"><strong>kernel_image=</strong></span>"<span class="emphasis"><em><file></em></span>"
</span></dt><dd>
Specifies the kernel image, which to include in the UEFI executable. The
default is <span class="emphasis"><em>/lib/modules/<KERNEL-VERSION>/vmlinuz</em></span> or
<span class="emphasis"><em>/boot/vmlinuz-<KERNEL-VERSION></em></span>.
</dd><dt><span class="term">
<span class="strong"><strong>sbat=</strong></span>"<span class="emphasis"><em>parameters</em></span>"
</span></dt><dd>
Specifies the SBAT parameters, which to include in the UEFI executable. By default
the default SBAT string added is "sbat,1,SBAT Version,sbat,1,
<a class="ulink" href="https://github.com/rhboot/shim/blob/main/SBAT.md" target="_top">https://github.com/rhboot/shim/blob/main/SBAT.md</a>".
</dd><dt><span class="term">
<span class="strong"><strong>enhanced_cpio=</strong></span>"<span class="emphasis"><em>{yes|no}</em></span>"
</span></dt><dd>
Attempt to use the dracut-cpio binary, which optimizes archive creation for
copy-on-write filesystems (default=no).
When specified, initramfs archives are also padded to ensure optimal data
alignment for extent sharing. To retain reflink data deduplication benefits,
this should be used alongside the <span class="strong"><strong>compress="cat"</strong></span> and <span class="strong"><strong>do_strip="no"</strong></span>
parameters, with initramfs source files, <span class="strong"><strong>tmpdir</strong></span> staging area and
destination all on the same copy-on-write capable filesystem.
</dd><dt><span class="term">
<span class="strong"><strong>parallel=</strong></span>"<span class="emphasis"><em>{yes|no}</em></span>"
</span></dt><dd>
If set to <span class="emphasis"><em>yes</em></span>, try to execute tasks in parallel (currently only supported
for <span class="emphasis"><em>--regenerate-all</em></span>).
</dd></dl></div></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="_files_2"></a>Files</h2></div></div></div><div class="variablelist"><dl class="variablelist"><dt><span class="term">
<span class="emphasis"><em>/etc/dracut.conf</em></span>
</span></dt><dd>
Old configuration file. You better use your own file in
<span class="emphasis"><em>/etc/dracut.conf.d/</em></span>.
</dd><dt><span class="term">
<span class="emphasis"><em>/etc/dracut.conf.d/</em></span>
</span></dt><dd>
Any <span class="emphasis"><em>/etc/dracut.conf.d/*.conf</em></span> file can override the values in
<span class="emphasis"><em>/etc/dracut.conf</em></span>. The configuration files are read in alphanumerical
order.
</dd></dl></div></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="_author"></a>AUTHOR</h2></div></div></div><p>Harald Hoyer</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="_see_also_2"></a>See Also</h2></div></div></div><p><span class="strong"><strong>dracut</strong></span>(8) <span class="strong"><strong>dracut.cmdline</strong></span>(7)</p></div></div><div class="chapter"><div class="titlepage"><div><div><h2 class="title"><a id="dracutcmdline7"></a>Chapter 8. DRACUT.CMDLINE(7)</h2></div></div></div><div class="toc"><p><strong>Table of Contents</strong></p><dl class="toc"><dt><span class="section"><a href="#_name_3">NAME</a></span></dt><dt><span class="section"><a href="#_description_3">DESCRIPTION</a></span></dt><dd><dl><dt><span class="section"><a href="#_standard">Standard</a></span></dt><dt><span class="section"><a href="#_iso_scan_filename">iso-scan/filename</a></span></dt><dt><span class="section"><a href="#_misc">Misc</a></span></dt><dt><span class="section"><a href="#dracutkerneldebug">Debug</a></span></dt><dt><span class="section"><a href="#_i18n">I18N</a></span></dt><dt><span class="section"><a href="#_lvm">LVM</a></span></dt><dt><span class="section"><a href="#_crypto_luks">crypto LUKS</a></span></dt><dt><span class="section"><a href="#_crypto_luks_key_on_removable_device_support">crypto LUKS - key on removable device support</a></span></dt><dt><span class="section"><a href="#_md_raid">MD RAID</a></span></dt><dt><span class="section"><a href="#_dm_raid">DM RAID</a></span></dt><dt><span class="section"><a href="#_multipath">MULTIPATH</a></span></dt><dt><span class="section"><a href="#_fips">FIPS</a></span></dt><dt><span class="section"><a href="#_network">Network</a></span></dt><dt><span class="section"><a href="#_nfs">NFS</a></span></dt><dt><span class="section"><a href="#_cifs">CIFS</a></span></dt><dt><span class="section"><a href="#_iscsi">iSCSI</a></span></dt><dt><span class="section"><a href="#_fcoe">FCoE</a></span></dt><dt><span class="section"><a href="#_nvmf">NVMf</a></span></dt><dt><span class="section"><a href="#_nbd">NBD</a></span></dt><dt><span class="section"><a href="#_virtiofs">VIRTIOFS</a></span></dt><dt><span class="section"><a href="#_dasd">DASD</a></span></dt><dt><span class="section"><a href="#_zfcp">ZFCP</a></span></dt><dt><span class="section"><a href="#_znet">ZNET</a></span></dt><dt><span class="section"><a href="#_booting_live_images">Booting live images</a></span></dt><dt><span class="section"><a href="#_zipl">ZIPL</a></span></dt><dt><span class="section"><a href="#_cio_ignore">CIO_IGNORE</a></span></dt><dt><span class="section"><a href="#_plymouth_boot_splash">Plymouth Boot Splash</a></span></dt><dt><span class="section"><a href="#_kernel_keys">Kernel keys</a></span></dt><dt><span class="section"><a href="#_deprecated_renamed_options">Deprecated, renamed Options</a></span></dt><dt><span class="section"><a href="#_configuration_in_the_initramfs_2">Configuration in the Initramfs</a></span></dt></dl></dd><dt><span class="section"><a href="#_author_2">AUTHOR</a></span></dt><dt><span class="section"><a href="#_see_also_3">SEE ALSO</a></span></dt></dl></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="_name_3"></a>NAME</h2></div></div></div><p>dracut.cmdline - dracut kernel command line options</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="_description_3"></a>DESCRIPTION</h2></div></div></div><p>The root device used by the kernel is specified in the boot configuration
file on the kernel command line, as always.</p><p>The traditional <span class="emphasis"><em>root=/dev/sda1</em></span> style device specification is allowed, but not
encouraged. The root device should better be identified by LABEL or UUID. If a
label is used, as in <span class="emphasis"><em>root=LABEL=<label_of_root></em></span> the initramfs will search all
available devices for a filesystem with the appropriate label, and mount that
device as the root filesystem. <span class="emphasis"><em>root=UUID=<uuidnumber></em></span> will mount the partition
with that UUID as the root filesystem.</p><p>In the following all kernel command line parameters, which are processed by
dracut, are described.</p><p>"rd.*" parameters mentioned without "=" are boolean parameters. They can be
turned on/off by setting them to {0|1}. If the assignment with "=" is missing
"=1" is implied. For example <span class="emphasis"><em>rd.info</em></span> can be turned off with <span class="emphasis"><em>rd.info=0</em></span> or
turned on with <span class="emphasis"><em>rd.info=1</em></span> or <span class="emphasis"><em>rd.info</em></span>. The last value in the kernel command
line is the value, which is honored.</p><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_standard"></a>Standard</h3></div></div></div><div class="variablelist"><dl class="variablelist"><dt><span class="term">
<span class="strong"><strong>init=</strong></span><span class="emphasis"><em><path to real init></em></span>
</span></dt><dd>
specify the path to the init program to be started after the initramfs has
finished
</dd><dt><span class="term">
<span class="strong"><strong>root=</strong></span><span class="emphasis"><em><path to blockdevice></em></span>
</span></dt><dd><p class="simpara">
specify the block device to use as the root filesystem.
</p><p><strong>Example. </strong>
</p><pre class="screen">root=/dev/sda1
root=/dev/disk/by-path/pci-0000:00:1f.1-scsi-0:0:1:0-part1
root=/dev/disk/by-label/Root
root=LABEL=Root
root=/dev/disk/by-uuid/3f5ad593-4546-4a94-a374-bcfb68aa11f7
root=UUID=3f5ad593-4546-4a94-a374-bcfb68aa11f7
root=PARTUUID=3f5ad593-4546-4a94-a374-bcfb68aa11f7</pre><p>
</p></dd><dt><span class="term">
<span class="strong"><strong>rootfstype=</strong></span><span class="emphasis"><em><filesystem type></em></span>
</span></dt><dd><p class="simpara">
"auto" if not specified.
</p><p><strong>Example. </strong>
</p><pre class="screen">rootfstype=ext3</pre><p>
</p></dd><dt><span class="term">
<span class="strong"><strong>rootflags=</strong></span><span class="emphasis"><em><mount options></em></span>
</span></dt><dd>
specify additional mount options for the root filesystem. If not set,
<span class="emphasis"><em>/etc/fstab</em></span> of the real root will be parsed for special mount options and
mounted accordingly.
</dd><dt><span class="term">
<span class="strong"><strong>ro</strong></span>
</span></dt><dd>
force mounting <span class="emphasis"><em>/</em></span> and <span class="emphasis"><em>/usr</em></span> (if it is a separate device) read-only. If
none of ro and rw is present, both are mounted according to <span class="emphasis"><em>/etc/fstab</em></span>.
</dd><dt><span class="term">
<span class="strong"><strong>rw</strong></span>
</span></dt><dd>
force mounting <span class="emphasis"><em>/</em></span> and <span class="emphasis"><em>/usr</em></span> (if it is a separate device) read-write.
See also ro option.
</dd><dt><span class="term">
<span class="strong"><strong>rootfallback=</strong></span><span class="emphasis"><em><path to blockdevice></em></span>
</span></dt><dd>
specify the block device to use as the root filesystem, if the normal root
cannot be found. This can only be a simple block device with a simple file
system, for which the filesystem driver is either compiled in, or added
manually to the initramfs. This parameter can be specified multiple times.
</dd><dt><span class="term">
<span class="strong"><strong>rd.auto</strong></span> <span class="strong"><strong>rd.auto=1</strong></span>
</span></dt><dd>
enable autoassembly of special devices like cryptoLUKS, dmraid, mdraid or
lvm. Default is off as of dracut version >= 024.
</dd><dt><span class="term">
<span class="strong"><strong>rd.hostonly=0</strong></span>
</span></dt><dd>
removes all compiled in configuration of the host system the initramfs image
was built on. This helps booting, if any disk layout changed, especially in
combination with rd.auto or other parameters specifying the layout.
</dd><dt><span class="term">
<span class="strong"><strong>rd.cmdline=ask</strong></span>
</span></dt><dd>
prompts the user for additional kernel command line parameters
</dd><dt><span class="term">
<span class="strong"><strong>rd.fstab=0</strong></span>
</span></dt><dd>
do not honor special mount options for the root filesystem found in
<span class="emphasis"><em>/etc/fstab</em></span> of the real root.
</dd><dt><span class="term">
<span class="strong"><strong>resume=</strong></span><span class="emphasis"><em><path to resume partition></em></span>
</span></dt><dd><p class="simpara">
resume from a swap partition
</p><p><strong>Example. </strong>
</p><pre class="screen">resume=/dev/disk/by-path/pci-0000:00:1f.1-scsi-0:0:1:0-part1
resume=/dev/disk/by-uuid/3f5ad593-4546-4a94-a374-bcfb68aa11f7
resume=UUID=3f5ad593-4546-4a94-a374-bcfb68aa11f7</pre><p>
</p></dd><dt><span class="term">
<span class="strong"><strong>rd.skipfsck</strong></span>
</span></dt><dd>
skip fsck for rootfs and <span class="emphasis"><em>/usr</em></span>. If you’re mounting <span class="emphasis"><em>/usr</em></span> read-only and
the init system performs fsck before remount, you might want to use this
option to avoid duplication.
</dd></dl></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_iso_scan_filename"></a>iso-scan/filename</h3></div></div></div><p>Mount all mountable devices and search for ISO pointed by the argument. When
the ISO is found set it up as a loop device. Device containing this ISO
image will stay mounted at /run/initramfs/isoscandev.
Using iso-scan/filename with a Fedora/Red Hat/CentOS Live iso should just work
by copying the original kernel cmdline parameters.</p><p><strong>Example. </strong>
</p><pre class="screen">menuentry 'Live Fedora 20' --class fedora --class gnu-linux --class gnu --class os {
set isolabel=Fedora-Live-LXDE-x86_64-20-1
set isofile="/boot/iso/Fedora-Live-LXDE-x86_64-20-1.iso"
loopback loop $isofile
linux (loop)/isolinux/vmlinuz0 boot=isolinux iso-scan/filename=$isofile root=live:LABEL=$isolabel ro rd.live.image quiet rhgb
initrd (loop)/isolinux/initrd0.img
}</pre><p>
</p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_misc"></a>Misc</h3></div></div></div><div class="variablelist"><dl class="variablelist"><dt><span class="term">
<span class="strong"><strong>rd.emergency=</strong></span><span class="emphasis"><em>[reboot|poweroff|halt]</em></span>
</span></dt><dd>
specify, what action to execute in case of a critical failure. rd.shell=0 must also
be specified.
</dd><dt><span class="term">
<span class="strong"><strong>rd.driver.blacklist=</strong></span><span class="emphasis"><em><drivername></em></span>[,<span class="emphasis"><em><drivername></em></span>,…]
</span></dt><dd>
do not load kernel module <drivername>. This parameter can be specified
multiple times.
</dd><dt><span class="term">
<span class="strong"><strong>rd.driver.pre=</strong></span><span class="emphasis"><em><drivername></em></span>[,<span class="emphasis"><em><drivername></em></span>,…]
</span></dt><dd>
force loading kernel module <drivername>. This parameter can be specified
multiple times.
</dd><dt><span class="term">
<span class="strong"><strong>rd.driver.post=</strong></span><span class="emphasis"><em><drivername></em></span>[,<span class="emphasis"><em><drivername></em></span>,…]
</span></dt><dd>
force loading kernel module <drivername> after all automatic loading modules
have been loaded. This parameter can be specified multiple times.
</dd><dt><span class="term">
<span class="strong"><strong>rd.retry=</strong></span><span class="emphasis"><em><seconds></em></span>
</span></dt><dd>
specify how long dracut should retry the initqueue to configure devices.
The default is 180 seconds. After 2/3 of the time, degraded raids are force
started. If you have hardware, which takes a very long time to announce its
drives, you might want to extend this value.
</dd><dt><span class="term">
<span class="strong"><strong>rd.timeout=</strong></span><span class="emphasis"><em><seconds></em></span>
</span></dt><dd>
specify how long dracut should wait for devices to appear. The
default is <span class="emphasis"><em>0</em></span>, which means <span class="emphasis"><em>forever</em></span>. Note that this timeout
should be longer than rd.retry to allow for proper configuration.
</dd><dt><span class="term">
<span class="strong"><strong>rd.noverifyssl</strong></span>
</span></dt><dd>
accept self-signed certificates for ssl downloads.
</dd><dt><span class="term">
<span class="strong"><strong>rd.ctty=</strong></span><span class="emphasis"><em><terminal device></em></span>
</span></dt><dd>
specify the controlling terminal for the console.
This is useful, if you have multiple "console=" arguments.
</dd><dt><span class="term">
<span class="strong"><strong>rd.shutdown.timeout.umount=</strong></span><span class="emphasis"><em><seconds></em></span>
</span></dt><dd>
specify how long dracut should wait for an individual umount to finish
during shutdown. This avoids the system from blocking when unmounting a file
system cannot complete and waits indefinitely. Value <span class="emphasis"><em>0</em></span> means to wait
<span class="emphasis"><em>forever</em></span>. The default is 90 seconds.
</dd></dl></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="dracutkerneldebug"></a>Debug</h3></div></div></div><p>If you are dropped to an emergency shell, the file
<span class="emphasis"><em>/run/initramfs/rdsosreport.txt</em></span> is created, which can be saved to a (to be
mounted by hand) partition (usually /boot) or a USB stick. Additional debugging
info can be produced by adding <span class="strong"><strong>rd.debug</strong></span> to the kernel command line.
<span class="emphasis"><em>/run/initramfs/rdsosreport.txt</em></span> contains all logs and the output of some tools.
It should be attached to any report about dracut problems.</p><div class="variablelist"><dl class="variablelist"><dt><span class="term">
<span class="strong"><strong>rd.info</strong></span>
</span></dt><dd>
print informational output though "quiet" is set
</dd><dt><span class="term">
<span class="strong"><strong>rd.shell</strong></span>
</span></dt><dd>
allow dropping to a shell, if root mounting fails
</dd><dt><span class="term">
<span class="strong"><strong>rd.debug</strong></span>
</span></dt><dd>
set -x for the dracut shell.
If systemd is active in the initramfs, all output is logged to the systemd
journal, which you can inspect with "journalctl -ab".
If systemd is not active, the logs are written to dmesg and
<span class="emphasis"><em>/run/initramfs/init.log</em></span>.
If "quiet" is set, it also logs to the console.
</dd><dt><span class="term">
<span class="strong"><strong>rd.memdebug=[0-5]</strong></span>
</span></dt><dd><p class="simpara">
Print memory usage info at various points, set the verbose level from 0 to 5.
</p><pre class="literallayout">Higher level means more debugging output:</pre><pre class="screen"> 0 - no output
1 - partial /proc/meminfo
2 - /proc/meminfo
3 - /proc/meminfo + /proc/slabinfo
4 - /proc/meminfo + /proc/slabinfo + memstrack summary
NOTE: memstrack is a memory tracing tool that tracks the total memory
consumption, and peak memory consumption of each kernel modules
and userspace progress during the whole initramfs runtime, report
is genereted and the end of initramsfs run.
5 - /proc/meminfo + /proc/slabinfo + memstrack (with top memory stacktrace)
NOTE: memstrack (with top memory stacktrace) will print top memory
allocation stack traces during the whole initramfs runtime.</pre></dd><dt><span class="term">
<span class="strong"><strong>rd.break</strong></span>
</span></dt><dd>
drop to a shell at the end
</dd><dt><span class="term">
<span class="strong"><strong>rd.break=</strong></span><span class="emphasis"><em>{cmdline|pre-udev|pre-trigger|initqueue|pre-mount|mount|pre-pivot|cleanup}</em></span>
</span></dt><dd>
drop to a shell on defined breakpoint
</dd><dt><span class="term">
<span class="strong"><strong>rd.udev.info</strong></span>
</span></dt><dd>
set udev to loglevel info
</dd><dt><span class="term">
<span class="strong"><strong>rd.udev.debug</strong></span>
</span></dt><dd>
set udev to loglevel debug
</dd></dl></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_i18n"></a>I18N</h3></div></div></div><div class="variablelist"><dl class="variablelist"><dt><span class="term">
<span class="strong"><strong>rd.vconsole.keymap=</strong></span><span class="emphasis"><em><keymap base file name></em></span>
</span></dt><dd><p class="simpara">
keyboard translation table loaded by loadkeys; taken from keymaps directory;
will be written as KEYMAP to <span class="emphasis"><em>/etc/vconsole.conf</em></span> in the initramfs.
</p><p><strong>Example. </strong>
</p><pre class="screen">rd.vconsole.keymap=de-latin1-nodeadkeys</pre><p>
</p></dd><dt><span class="term">
<span class="strong"><strong>rd.vconsole.keymap.ext=</strong></span><span class="emphasis"><em><list of keymap base file names></em></span>
</span></dt><dd>
list of extra keymaps to bo loaded (sep. by space); will be written as
EXT_KEYMAP to <span class="emphasis"><em>/etc/vconsole.conf</em></span> in the initramfs
</dd><dt><span class="term">
<span class="strong"><strong>rd.vconsole.unicode</strong></span>
</span></dt><dd>
boolean, indicating UTF-8 mode; will be written as UNICODE to
<span class="emphasis"><em>/etc/vconsole.conf</em></span> in the initramfs
</dd><dt><span class="term">
<span class="strong"><strong>rd.vconsole.font=</strong></span><span class="emphasis"><em><font base file name></em></span>
</span></dt><dd><p class="simpara">
console font; taken from consolefonts directory; will be written as FONT to
<span class="emphasis"><em>/etc/vconsole.conf</em></span> in the initramfs.
</p><p><strong>Example. </strong>
</p><pre class="screen">rd.vconsole.font=eurlatgr</pre><p>
</p></dd><dt><span class="term">
<span class="strong"><strong>rd.vconsole.font.map=</strong></span><span class="emphasis"><em><console map base file name></em></span>
</span></dt><dd>
see description of <span class="emphasis"><em>-m</em></span> parameter in setfont manual; taken from consoletrans
directory; will be written as FONT_MAP to <span class="emphasis"><em>/etc/vconsole.conf</em></span> in the
initramfs
</dd><dt><span class="term">
<span class="strong"><strong>rd.vconsole.font.unimap=</strong></span><span class="emphasis"><em><unicode table base file name></em></span>
</span></dt><dd>
see description of <span class="emphasis"><em>-u</em></span> parameter in setfont manual; taken from unimaps
directory; will be written as FONT_UNIMAP to <span class="emphasis"><em>/etc/vconsole.conf</em></span> in the
initramfs
</dd><dt><span class="term">
<span class="strong"><strong>rd.locale.LANG=</strong></span><span class="emphasis"><em><locale></em></span>
</span></dt><dd><p class="simpara">
taken from the environment; if no UNICODE is defined we set its value in
basis of LANG value (whether it ends with ".utf8" (or similar) or not); will
be written as LANG to <span class="emphasis"><em>/etc/locale.conf</em></span> in the initramfs.
</p><p><strong>Example. </strong>
</p><pre class="screen">rd.locale.LANG=pl_PL.utf8</pre><p>
</p></dd><dt><span class="term">
<span class="strong"><strong>rd.locale.LC_ALL=</strong></span><span class="emphasis"><em><locale></em></span>
</span></dt><dd>
taken from the environment; will be written as LC_ALL to <span class="emphasis"><em>/etc/locale.conf</em></span>
in the initramfs
</dd></dl></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_lvm"></a>LVM</h3></div></div></div><div class="variablelist"><dl class="variablelist"><dt><span class="term">
<span class="strong"><strong>rd.lvm=0</strong></span>
</span></dt><dd>
disable LVM detection
</dd><dt><span class="term">
<span class="strong"><strong>rd.lvm.vg=</strong></span><span class="emphasis"><em><volume group name></em></span>
</span></dt><dd>
only activate all logical volumes in the the volume groups with the given name.
rd.lvm.vg can be specified multiple times on the kernel command line.
</dd><dt><span class="term">
<span class="strong"><strong>rd.lvm.lv=</strong></span><span class="emphasis"><em><volume group name>/<logical volume name></em></span>
</span></dt><dd>
only activate the logical volumes with the given name.
rd.lvm.lv can be specified multiple times on the kernel command line.
</dd><dt><span class="term">
<span class="strong"><strong>rd.lvm.conf=0</strong></span>
</span></dt><dd>
remove any <span class="emphasis"><em>/etc/lvm/lvm.conf</em></span>, which may exist in the initramfs
</dd></dl></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_crypto_luks"></a>crypto LUKS</h3></div></div></div><div class="variablelist"><dl class="variablelist"><dt><span class="term">
<span class="strong"><strong>rd.luks=0</strong></span>
</span></dt><dd>
disable crypto LUKS detection
</dd><dt><span class="term">
<span class="strong"><strong>rd.luks.uuid=</strong></span><span class="emphasis"><em><luks uuid></em></span>
</span></dt><dd>
only activate the LUKS partitions with the given UUID. Any "luks-" of the
LUKS UUID is removed before comparing to <span class="emphasis"><em><luks uuid></em></span>.
The comparisons also matches, if <span class="emphasis"><em><luks uuid></em></span> is only the beginning of the
LUKS UUID, so you don’t have to specify the full UUID.
This parameter can be specified multiple times.
<span class="emphasis"><em><luks uuid></em></span> may be prefixed by the keyword <code class="literal">keysource:</code>, see
<span class="emphasis"><em>rd.luks.key</em></span> below.
</dd><dt><span class="term">
<span class="strong"><strong>rd.luks.allow-discards=</strong></span><span class="emphasis"><em><luks uuid></em></span>
</span></dt><dd>
Allow using of discards (TRIM) requests for LUKS partitions with the given
UUID. Any "luks-" of the LUKS UUID is removed before comparing to
<span class="emphasis"><em><luks uuid></em></span>. The comparisons also matches, if <span class="emphasis"><em><luks uuid></em></span> is only the
beginning of the LUKS UUID, so you don’t have to specify the full UUID.
This parameter can be specified multiple times.
</dd><dt><span class="term">
<span class="strong"><strong>rd.luks.allow-discards</strong></span>
</span></dt><dd>
Allow using of discards (TRIM) requests on all LUKS partitions.
</dd><dt><span class="term">
<span class="strong"><strong>rd.luks.crypttab=0</strong></span>
</span></dt><dd>
do not check, if LUKS partition is in <span class="emphasis"><em>/etc/crypttab</em></span>
</dd><dt><span class="term">
<span class="strong"><strong>rd.luks.timeout=</strong></span><span class="emphasis"><em><seconds></em></span>
</span></dt><dd>
specify how long dracut should wait when waiting for the user to enter the
password. This avoid blocking the boot if no password is entered. It does
not apply to luks key. The default is <span class="emphasis"><em>0</em></span>, which means <span class="emphasis"><em>forever</em></span>.
</dd></dl></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_crypto_luks_key_on_removable_device_support"></a>crypto LUKS - key on removable device support</h3></div></div></div><p>NB: If systemd is included in the dracut initrd, dracut’s built in
removable device keying support won’t work. systemd will prompt for
a password from the console even if you’ve supplied <span class="strong"><strong>rd.luks.key</strong></span>.
You may be able to use standard systemd <span class="strong"><strong>fstab</strong></span>(5) syntax to
get the same effect. If you do need <span class="strong"><strong>rd.luks.key</strong></span> to work,
you will have to exclude the "systemd" dracut module and any modules
that depend on it. See <span class="strong"><strong>dracut.conf</strong></span>(5) and
<a class="ulink" href="https://bugzilla.redhat.com/show_bug.cgi?id=905683" target="_top">https://bugzilla.redhat.com/show_bug.cgi?id=905683</a> for more
information.</p><div class="variablelist"><dl class="variablelist"><dt><span class="term">
<span class="strong"><strong>rd.luks.key=</strong></span><span class="emphasis"><em><keypath>[:<keydev>[:<luksdev>]]</em></span>
</span></dt><dd><p class="simpara">
<span class="emphasis"><em><keypath></em></span> is the pathname of a key file, relative to the root
of the filesystem on some device. It’s REQUIRED. When
<span class="emphasis"><em><keypath></em></span> ends with <span class="emphasis"><em>.gpg</em></span> it’s considered to be key encrypted
symmetrically with GPG. You will be prompted for the GPG password on
boot. GPG support comes with the <span class="emphasis"><em>crypt-gpg</em></span> module, which needs to be
added explicitly.
</p><p class="simpara"><span class="emphasis"><em><keydev></em></span> identifies the device on which the key file resides. It may
be the kernel name of the device (should start with "/dev/"), a UUID
(prefixed with "UUID=") or a label (prefix with "LABEL="). You don’t
have to specify a full UUID. Just its beginning will suffice, even if
its ambiguous. All matching devices will be probed. This parameter is
recommended, but not required. If it’s not present, all block devices will
be probed, which may significantly increase boot time.</p><p class="simpara">If <span class="emphasis"><em><luksdev></em></span> is given, the specified key will only be used for
the specified LUKS device. Possible values are the same as for
<span class="emphasis"><em><keydev></em></span>. Unless you have several LUKS devices, you don’t have to
specify this parameter. The simplest usage is:</p><p><strong>Example. </strong>
</p><pre class="screen">rd.luks.key=/foo/bar.key</pre><p>
</p><p class="simpara">As you see, you can skip colons in such a case.</p></dd></dl></div><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>Your LUKS partition must match your key file.</p><p>dracut provides keys to cryptsetup with <span class="emphasis"><em>-d</em></span> (an older alias for
<span class="emphasis"><em>--key-file</em></span>). This uses the entire binary
content of the key file as part of the secret. If
you pipe a password into cryptsetup <span class="strong"><strong>without</strong></span> <span class="emphasis"><em>-d</em></span> or <span class="emphasis"><em>--key-file</em></span>,
it will be treated as text user input, and only characters before
the first newline will be used. Therefore, when you’re creating
an encrypted partition for dracut to mount, and you pipe a key into
<span class="emphasis"><em>cryptsetup luksFormat</em></span>,you must use <span class="emphasis"><em>-d -</em></span>.</p><p>Here is an example for a key encrypted with GPG (warning:
<span class="emphasis"><em>--batch-mode</em></span> will overwrite the device without asking for
confirmation):</p><pre class="screen">gpg --quiet --decrypt rootkey.gpg | \
cryptsetup --batch-mode --key-file - \
luksFormat /dev/sda47</pre><p>If you use unencrypted key files, just use the key file pathname
instead of the standard input. For a random key with 256 bits of
entropy, you might use:</p><pre class="screen">head -32c /dev/urandom > rootkey.key
cryptsetup --batch-mode --key-file rootkey.key \
luksFormat /dev/sda47</pre><p>You can also use regular key files on an encrypted <span class="emphasis"><em>keydev</em></span>.</p><p>Compared to using GPG encrypted keyfiles on an unencrypted
device this provides the following advantages:</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">
you can unlock your disk(s) using multiple passphrases
</li><li class="listitem">
better security by not loosing the key stretching mechanism
</li></ul></div><p>To use an encrypted <span class="emphasis"><em>keydev</em></span> you <span class="strong"><strong>must</strong></span> ensure that it becomes
available by using the keyword <code class="literal">keysource</code>, e.g.
<code class="literal">rd.luks.uuid=keysource:aaaa</code>
<span class="emphasis"><em>aaaa</em></span> being the uuid of the encrypted <span class="emphasis"><em>keydev</em></span>.</p><p>Example:</p><p>Lets assume you have three disks <span class="emphasis"><em>A</em></span>, <span class="emphasis"><em>B</em></span> and <span class="emphasis"><em>C</em></span> with the uuids
<span class="emphasis"><em>aaaa</em></span>, <span class="emphasis"><em>bbbb</em></span> and <span class="emphasis"><em>cccc</em></span>.
You want to unlock <span class="emphasis"><em>A</em></span> and <span class="emphasis"><em>B</em></span> using keyfile <span class="emphasis"><em>keyfile</em></span>.
The unlocked volumes be <span class="emphasis"><em>A'</em></span>, <span class="emphasis"><em>B'</em></span> and <span class="emphasis"><em>C'</em></span> with the uuids
<span class="emphasis"><em>AAAA</em></span>, <span class="emphasis"><em>BBBB</em></span> and <span class="emphasis"><em>CCCC</em></span>.
<span class="emphasis"><em>keyfile</em></span> is saved on <span class="emphasis"><em>C'</em></span> as <span class="emphasis"><em>/keyfile</em></span>.</p><p>One luks keyslot of each <span class="emphasis"><em>A</em></span>, <span class="emphasis"><em>B</em></span> and <span class="emphasis"><em>C</em></span> is setup with a
passphrase.
Another luks keyslot of each <span class="emphasis"><em>A</em></span> and <span class="emphasis"><em>B</em></span> is setup with <span class="emphasis"><em>keyfile</em></span>.</p><p>To boot this configuration you could use:</p><pre class="screen">rd.luks.uuid=aaaa
rd.luks.uuid=bbbb
rd.luks.uuid=keysource:cccc
rd.luks.key=/keyfile:UUID=CCCC</pre><p>Dracut asks for the passphrase for <span class="emphasis"><em>C</em></span> and uses the
keyfile to unlock <span class="emphasis"><em>A</em></span> and <span class="emphasis"><em>B</em></span>.
If getting the passphrase for <span class="emphasis"><em>C</em></span> fails it falls back to
asking for the passphrases for <span class="emphasis"><em>A</em></span> and <span class="emphasis"><em>B</em></span>.</p><p>If you want <span class="emphasis"><em>C'</em></span> to stay unlocked, specify a luks name for
it, e.g. <code class="literal">rd.luks.name=cccc=mykeys</code>, otherwise it gets closed
when not needed anymore.</p></div><div class="variablelist"><dl class="variablelist"><dt><span class="term">
<span class="strong"><strong>rd.luks.key.tout=0</strong></span>
</span></dt><dd>
specify how many times dracut will try to read the keys specified in in
rd.luk.key. This gives a chance to the removable device containing the key
to initialise.
</dd></dl></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_md_raid"></a>MD RAID</h3></div></div></div><div class="variablelist"><dl class="variablelist"><dt><span class="term">
<span class="strong"><strong>rd.md=0</strong></span>
</span></dt><dd>
disable MD RAID detection
</dd><dt><span class="term">
<span class="strong"><strong>rd.md.imsm=0</strong></span>
</span></dt><dd>
disable MD RAID for imsm/isw raids, use DM RAID instead
</dd><dt><span class="term">
<span class="strong"><strong>rd.md.ddf=0</strong></span>
</span></dt><dd>
disable MD RAID for SNIA ddf raids, use DM RAID instead
</dd><dt><span class="term">
<span class="strong"><strong>rd.md.conf=0</strong></span>
</span></dt><dd>
ignore mdadm.conf included in initramfs
</dd><dt><span class="term">
<span class="strong"><strong>rd.md.waitclean=1</strong></span>
</span></dt><dd>
wait for any resync, recovery, or reshape activity to finish before
continuing
</dd><dt><span class="term">
<span class="strong"><strong>rd.md.uuid=</strong></span><span class="emphasis"><em><md raid uuid></em></span>
</span></dt><dd>
only activate the raid sets with the given UUID. This parameter can be
specified multiple times.
</dd></dl></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_dm_raid"></a>DM RAID</h3></div></div></div><div class="variablelist"><dl class="variablelist"><dt><span class="term">
<span class="strong"><strong>rd.dm=0</strong></span>
</span></dt><dd>
disable DM RAID detection
</dd><dt><span class="term">
<span class="strong"><strong>rd.dm.uuid=</strong></span><span class="emphasis"><em><dm raid uuid></em></span>
</span></dt><dd>
only activate the raid sets with the given UUID. This parameter can be
specified multiple times.
</dd></dl></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_multipath"></a>MULTIPATH</h3></div></div></div><div class="variablelist"><dl class="variablelist"><dt><span class="term">
<span class="strong"><strong>rd.multipath=0</strong></span>
</span></dt><dd>
disable multipath detection
</dd><dt><span class="term">
<span class="strong"><strong>rd.multipath=default</strong></span>
</span></dt><dd>
use default multipath settings
</dd></dl></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_fips"></a>FIPS</h3></div></div></div><div class="variablelist"><dl class="variablelist"><dt><span class="term">
<span class="strong"><strong>rd.fips</strong></span>
</span></dt><dd>
enable FIPS
</dd><dt><span class="term">
<span class="strong"><strong>boot=</strong></span><span class="emphasis"><em><boot device></em></span>
</span></dt><dd><p class="simpara">
specify the device, where /boot is located.
</p><p><strong>Example. </strong>
</p><pre class="screen">boot=/dev/sda1
boot=/dev/disk/by-path/pci-0000:00:1f.1-scsi-0:0:1:0-part1
boot=UUID=<uuid>
boot=LABEL=<label></pre><p>
</p></dd><dt><span class="term">
<span class="strong"><strong>rd.fips.skipkernel</strong></span>
</span></dt><dd>
skip checksum check of the kernel image. Useful, if the kernel image is not
in a separate boot partition.
</dd></dl></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_network"></a>Network</h3></div></div></div><div class="important" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Important</h3><p>It is recommended to either bind an interface to a MAC with the <span class="strong"><strong>ifname</strong></span>
argument, or to use the systemd-udevd predictable network interface names.</p><p>Predictable network interface device names based on:</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">
firmware/bios-provided index numbers for on-board devices
</li><li class="listitem">
firmware-provided pci-express hotplug slot index number
</li><li class="listitem">
physical/geographical location of the hardware
</li><li class="listitem">
the interface’s MAC address
</li></ul></div><p>See:
<a class="ulink" href="http://www.freedesktop.org/wiki/Software/systemd/PredictableNetworkInterfaceNames" target="_top">http://www.freedesktop.org/wiki/Software/systemd/PredictableNetworkInterfaceNames</a></p><p>Two character prefixes based on the type of interface:</p><div class="variablelist"><dl class="variablelist"><dt><span class="term">
en
</span></dt><dd>
ethernet
</dd><dt><span class="term">
wl
</span></dt><dd>
wlan
</dd><dt><span class="term">
ww
</span></dt><dd>
wwan
</dd></dl></div><p>Type of names:</p><div class="variablelist"><dl class="variablelist"><dt><span class="term">
o<index>
</span></dt><dd>
on-board device index number
</dd><dt><span class="term">
s<slot>[f<function>][d<dev_id>]
</span></dt><dd>
hotplug slot index number
</dd><dt><span class="term">
x<MAC>
</span></dt><dd>
MAC address
</dd><dt><span class="term">
[P<domain>]p<bus>s<slot>[f<function>][d<dev_id>]
</span></dt><dd>
PCI geographical location
</dd><dt><span class="term">
[P<domain>]p<bus>s<slot>[f<function>][u<port>][..][c<config>][i<interface>]
</span></dt><dd>
USB port number chain
</dd></dl></div><p>All multi-function PCI devices will carry the [f<function>] number in the
device name, including the function 0 device.</p><p>When using PCI geography, The PCI domain is only prepended when it is not 0.</p><p>For USB devices the full chain of port numbers of hubs is composed. If the
name gets longer than the maximum number of 15 characters, the name is not
exported.
The usual USB configuration == 1 and interface == 0 values are suppressed.</p><div class="variablelist"><dl class="variablelist"><dt><span class="term">
PCI ethernet card with firmware index "1"
</span></dt><dd><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">
eno1
</li></ul></div></dd><dt><span class="term">
PCI ethernet card in hotplug slot with firmware index number
</span></dt><dd><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">
ens1
</li></ul></div></dd><dt><span class="term">
PCI ethernet multi-function card with 2 ports
</span></dt><dd><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">
enp2s0f0
</li><li class="listitem">
enp2s0f1
</li></ul></div></dd><dt><span class="term">
PCI wlan card
</span></dt><dd><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">
wlp3s0
</li></ul></div></dd><dt><span class="term">
USB built-in 3G modem
</span></dt><dd><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">
wwp0s29u1u4i6
</li></ul></div></dd><dt><span class="term">
USB Android phone
</span></dt><dd><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">
enp0s29u1u2
</li></ul></div></dd></dl></div></div><p>The following options are supported by the <span class="emphasis"><em>network-legacy</em></span> dracut
module. Other network modules might support a slightly different set of
options; refer to the documentation of the specific network module in use. For
NetworkManager, see <span class="strong"><strong>nm-initrd-generator</strong></span>(8).</p><div class="variablelist"><dl class="variablelist"><dt><span class="term">
<span class="strong"><strong>ip=</strong></span><span class="emphasis"><em>{dhcp|on|any|dhcp6|auto6|either6|link6|single-dhcp}</em></span>
</span></dt><dd><div class="variablelist"><dl class="variablelist"><dt><span class="term">
dhcp|on|any
</span></dt><dd>
get ip from dhcp server from all interfaces. If netroot=dhcp,
loop sequentially through all interfaces (eth0, eth1, …) and use the first
with a valid DHCP root-path.
</dd><dt><span class="term">
single-dhcp
</span></dt><dd>
Send DHCP on all available interfaces in parallel, as
opposed to one after another. After the first DHCP response is received,
stop DHCP on all other interfaces. This gives the fastest boot time by
using the IP on interface for which DHCP succeeded first during early boot.
Caveat: Does not apply to Network Manager and to SUSE using wicked.
</dd><dt><span class="term">
auto6
</span></dt><dd>
IPv6 autoconfiguration
</dd><dt><span class="term">
dhcp6
</span></dt><dd>
IPv6 DHCP
</dd><dt><span class="term">
either6
</span></dt><dd>
if auto6 fails, then dhcp6
</dd><dt><span class="term">
link6
</span></dt><dd>
bring up interface for IPv6 link-local addressing
</dd></dl></div></dd><dt><span class="term">
<span class="strong"><strong>ip=</strong></span><span class="emphasis"><em><interface></em></span>:<span class="emphasis"><em>{dhcp|on|any|dhcp6|auto6|link6}</em></span>[:[<span class="emphasis"><em><mtu></em></span>][:<span class="emphasis"><em><macaddr></em></span>]]
</span></dt><dd><p class="simpara">
This parameter can be specified multiple times.
</p><div class="informalexample"><div class="variablelist"><dl class="variablelist"><dt><span class="term">
dhcp|on|any|dhcp6
</span></dt><dd>
get ip from dhcp server on a specific interface
</dd><dt><span class="term">
auto6
</span></dt><dd>
do IPv6 autoconfiguration
</dd><dt><span class="term">
link6
</span></dt><dd>
bring up interface for IPv6 link local address
</dd><dt><span class="term">
<macaddr>
</span></dt><dd>
optionally <span class="strong"><strong>set</strong></span> <macaddr> on the <interface>. This
cannot be used in conjunction with the <span class="strong"><strong>ifname</strong></span> argument for the
same <interface>.
</dd></dl></div></div></dd><dt><span class="term">
<span class="strong"><strong>ip=</strong></span><span class="emphasis"><em><client-IP></em></span>:[<span class="emphasis"><em><peer></em></span>]:<span class="emphasis"><em><gateway-IP></em></span>:<span class="emphasis"><em><netmask></em></span>:<span class="emphasis"><em><client_hostname></em></span>:<span class="emphasis"><em><interface></em></span>:<span class="emphasis"><em>{none|off|dhcp|on|any|dhcp6|auto6|ibft}</em></span>[:[<span class="emphasis"><em><mtu></em></span>][:<span class="emphasis"><em><macaddr></em></span>]]
</span></dt><dd><p class="simpara">
explicit network configuration. If you want do define a IPv6 address, put it
in brackets (e.g. [2001:DB8::1]). This parameter can be specified multiple
times. <span class="emphasis"><em><peer></em></span> is optional and is the address of the remote endpoint
for pointopoint interfaces and it may be followed by a slash and a decimal
number, encoding the network prefix length.
</p><div class="informalexample"><div class="variablelist"><dl class="variablelist"><dt><span class="term">
<macaddr>
</span></dt><dd>
optionally <span class="strong"><strong>set</strong></span> <macaddr> on the <interface>. This
cannot be used in conjunction with the <span class="strong"><strong>ifname</strong></span> argument for the
same <interface>.
</dd></dl></div></div></dd><dt><span class="term">
<span class="strong"><strong>ip=</strong></span><span class="emphasis"><em><client-IP></em></span>:[<span class="emphasis"><em><peer></em></span>]:<span class="emphasis"><em><gateway-IP></em></span>:<span class="emphasis"><em><netmask></em></span>:<span class="emphasis"><em><client_hostname></em></span>:<span class="emphasis"><em><interface></em></span>:<span class="emphasis"><em>{none|off|dhcp|on|any|dhcp6|auto6|ibft}</em></span>[:[<span class="emphasis"><em><dns1></em></span>][:<span class="emphasis"><em><dns2></em></span>]]
</span></dt><dd>
explicit network configuration. If you want do define a IPv6 address, put it
in brackets (e.g. [2001:DB8::1]). This parameter can be specified multiple
times. <span class="emphasis"><em><peer></em></span> is optional and is the address of the remote endpoint
for pointopoint interfaces and it may be followed by a slash and a decimal
number, encoding the network prefix length.
</dd><dt><span class="term">
<span class="strong"><strong>ifname=</strong></span><span class="emphasis"><em><interface></em></span>:<span class="emphasis"><em><MAC></em></span>
</span></dt><dd><p class="simpara">
Assign network device name <interface> (i.e. "bootnet") to the NIC with
MAC <MAC>.
</p><div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Warning</h3><p>Do <span class="strong"><strong>not</strong></span> use the default kernel naming scheme for the interface name,
as it can conflict with the kernel names. So, don’t use "eth[0-9]+" for the
interface name. Better name it "bootnet" or "bluesocket".</p></div></dd><dt><span class="term">
<span class="strong"><strong>rd.route=</strong></span><span class="emphasis"><em><net></em></span>/<span class="emphasis"><em><netmask></em></span>:<span class="emphasis"><em><gateway></em></span>[:<span class="emphasis"><em><interface></em></span>]
</span></dt><dd><p class="simpara">
Add a static route with route options, which are separated by a colon.
IPv6 addresses have to be put in brackets.
</p><p><strong>Example. </strong>
</p><pre class="screen"> rd.route=192.168.200.0/24:192.168.100.222:ens10
rd.route=192.168.200.0/24:192.168.100.222
rd.route=192.168.200.0/24::ens10
rd.route=[2001:DB8:3::/8]:[2001:DB8:2::1]:ens10</pre><p>
</p></dd><dt><span class="term">
<span class="strong"><strong>bootdev=</strong></span><span class="emphasis"><em><interface></em></span>
</span></dt><dd>
specify network interface to use routing and netroot information from.
Required if multiple ip= lines are used.
</dd><dt><span class="term">
<span class="strong"><strong>BOOTIF=</strong></span><span class="emphasis"><em><MAC></em></span>
</span></dt><dd>
specify network interface to use routing and netroot information from.
</dd><dt><span class="term">
<span class="strong"><strong>rd.bootif=0</strong></span>
</span></dt><dd>
Disable BOOTIF parsing, which is provided by PXE
</dd><dt><span class="term">
<span class="strong"><strong>nameserver=</strong></span><span class="emphasis"><em><IP></em></span> [<span class="strong"><strong>nameserver=</strong></span><span class="emphasis"><em><IP></em></span> …]
</span></dt><dd>
specify nameserver(s) to use
</dd><dt><span class="term">
<span class="strong"><strong>rd.peerdns=0</strong></span>
</span></dt><dd>
Disable DNS setting of DHCP parameters.
</dd><dt><span class="term">
<span class="strong"><strong>biosdevname=0</strong></span>
</span></dt><dd>
boolean, turn off biosdevname network interface renaming
</dd><dt><span class="term">
<span class="strong"><strong>rd.neednet=1</strong></span>
</span></dt><dd>
boolean, bring up network even without netroot set
</dd><dt><span class="term">
<span class="strong"><strong>vlan=</strong></span><span class="emphasis"><em><vlanname></em></span>:<span class="emphasis"><em><phydevice></em></span>
</span></dt><dd>
Setup vlan device named <vlanname> on <phydevice>.
We support the four styles of vlan names: VLAN_PLUS_VID (vlan0005),
VLAN_PLUS_VID_NO_PAD (vlan5), DEV_PLUS_VID (eth0.0005),
DEV_PLUS_VID_NO_PAD (eth0.5)
</dd><dt><span class="term">
<span class="strong"><strong>bond=</strong></span><span class="emphasis"><em><bondname></em></span>[:<span class="emphasis"><em><bondslaves></em></span>:[:<span class="emphasis"><em><options></em></span>[:<mtu>]]]
</span></dt><dd>
Setup bonding device <bondname> on top of <bondslaves>.
<bondslaves> is a comma-separated list of physical (ethernet) interfaces.
<options> is a comma-separated list on bonding options (modinfo bonding for
details) in format compatible with initscripts. If <options> includes
multi-valued arp_ip_target option, then its values should be separated by
semicolon. if the mtu is specified, it will be set on the bond master.
Bond without parameters assumes
bond=bond0:eth0,eth1:mode=balance-rr
</dd><dt><span class="term">
<span class="strong"><strong>team=</strong></span><span class="emphasis"><em><teammaster></em></span>:<span class="emphasis"><em><teamslaves></em></span>[:<span class="emphasis"><em><teamrunner></em></span>]
</span></dt><dd>
Setup team device <teammaster> on top of <teamslaves>.
<teamslaves> is a comma-separated list of physical (ethernet) interfaces.
<teamrunner> is the runner type to be used (see <span class="strong"><strong>teamd.conf</strong></span>(5)); defaults to
activebackup.
Team without parameters assumes
team=team0:eth0,eth1:activebackup
</dd><dt><span class="term">
<span class="strong"><strong>bridge=</strong></span><span class="emphasis"><em><bridgename></em></span>:<span class="emphasis"><em><ethnames></em></span>
</span></dt><dd>
Setup bridge <bridgename> with <ethnames>. <ethnames> is a comma-separated
list of physical (ethernet) interfaces. Bridge without parameters assumes
bridge=br0:eth0
</dd></dl></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_nfs"></a>NFS</h3></div></div></div><div class="variablelist"><dl class="variablelist"><dt><span class="term">
<span class="strong"><strong>root=</strong></span>[<span class="emphasis"><em><server-ip></em></span>:]<span class="emphasis"><em><root-dir></em></span>[:<span class="emphasis"><em><nfs-options></em></span>]
</span></dt><dd>
mount nfs share from <server-ip>:/<root-dir>, if no server-ip is given, use
dhcp next_server. If server-ip is an IPv6 address it has to be put in
brackets, e.g. [2001:DB8::1]. NFS options can be appended with the prefix
":" or "," and are separated by ",".
</dd><dt><span class="term">
<span class="strong"><strong>root=</strong></span>nfs:[<span class="emphasis"><em><server-ip></em></span>:]<span class="emphasis"><em><root-dir></em></span>[:<span class="emphasis"><em><nfs-options></em></span>], <span class="strong"><strong>root=</strong></span>nfs4:[<span class="emphasis"><em><server-ip></em></span>:]<span class="emphasis"><em><root-dir></em></span>[:<span class="emphasis"><em><nfs-options></em></span>], <span class="strong"><strong>root=</strong></span><span class="emphasis"><em>{dhcp|dhcp6}</em></span>
</span></dt><dd><p class="simpara">
netroot=dhcp alone directs initrd to look at the DHCP root-path where NFS
options can be specified.
</p><p><strong>Example. </strong>
</p><pre class="screen"> root-path=<server-ip>:<root-dir>[,<nfs-options>]
root-path=nfs:<server-ip>:<root-dir>[,<nfs-options>]
root-path=nfs4:<server-ip>:<root-dir>[,<nfs-options>]</pre><p>
</p></dd><dt><span class="term">
<span class="strong"><strong>root=</strong></span><span class="emphasis"><em>/dev/nfs</em></span> nfsroot=[<span class="emphasis"><em><server-ip></em></span>:]<span class="emphasis"><em><root-dir></em></span>[:<span class="emphasis"><em><nfs-options></em></span>]
</span></dt><dd>
<span class="emphasis"><em>Deprecated!</em></span> kernel Documentation_/filesystems/nfsroot.txt_ defines this
method. This is supported by dracut, but not recommended.
</dd><dt><span class="term">
<span class="strong"><strong>rd.nfs.domain=</strong></span><span class="emphasis"><em><NFSv4 domain name></em></span>
</span></dt><dd>
Set the NFSv4 domain name. Will override the settings in <span class="emphasis"><em>/etc/idmap.conf</em></span>.
</dd><dt><span class="term">
<span class="strong"><strong>rd.net.dhcp.retry=</strong></span><span class="emphasis"><em><cnt></em></span>
</span></dt><dd>
If this option is set, dracut will try to connect via dhcp <cnt> times before failing.
Default is 1.
</dd><dt><span class="term">
<span class="strong"><strong>rd.net.timeout.dhcp=</strong></span><span class="emphasis"><em><arg></em></span>
</span></dt><dd>
If this option is set, dhclient is called with "-timeout <arg>".
</dd><dt><span class="term">
<span class="strong"><strong>rd.net.timeout.iflink=</strong></span><span class="emphasis"><em><seconds></em></span>
</span></dt><dd>
Wait <seconds> until link shows up. Default is 60 seconds.
</dd><dt><span class="term">
<span class="strong"><strong>rd.net.timeout.ifup=</strong></span><span class="emphasis"><em><seconds></em></span>
</span></dt><dd>
Wait <seconds> until link has state "UP". Default is 20 seconds.
</dd><dt><span class="term">
<span class="strong"><strong>rd.net.timeout.route=</strong></span><span class="emphasis"><em><seconds></em></span>
</span></dt><dd>
Wait <seconds> until route shows up. Default is 20 seconds.
</dd><dt><span class="term">
<span class="strong"><strong>rd.net.timeout.ipv6dad=</strong></span><span class="emphasis"><em><seconds></em></span>
</span></dt><dd>
Wait <seconds> until IPv6 DAD is finished. Default is 50 seconds.
</dd><dt><span class="term">
<span class="strong"><strong>rd.net.timeout.ipv6auto=</strong></span><span class="emphasis"><em><seconds></em></span>
</span></dt><dd>
Wait <seconds> until IPv6 automatic addresses are assigned. Default is 40 seconds.
</dd><dt><span class="term">
<span class="strong"><strong>rd.net.timeout.carrier=</strong></span><span class="emphasis"><em><seconds></em></span>
</span></dt><dd>
Wait <seconds> until carrier is recognized. Default is 10 seconds.
</dd></dl></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_cifs"></a>CIFS</h3></div></div></div><div class="variablelist"><dl class="variablelist"><dt><span class="term">
<span class="strong"><strong>root=</strong></span>cifs://[<span class="emphasis"><em><username></em></span>[:<span class="emphasis"><em><password></em></span>]@]<span class="emphasis"><em><server-ip></em></span>:<span class="emphasis"><em><root-dir></em></span>
</span></dt><dd><p class="simpara">
mount cifs share from <server-ip>:/<root-dir>, if no server-ip is given, use
dhcp next_server. if server-ip is an IPv6 address it has to be put in
brackets, e.g. [2001:DB8::1]. If a username or password are not specified
as part of the root, then they must be passed on the command line through
cifsuser/cifspass.
</p><div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Warning</h3><p>Passwords specified on the kernel command line are visible for all
users via the file <span class="emphasis"><em>/proc/cmdline</em></span> and via dmesg or can be sniffed on the
network, when using DHCP with DHCP root-path.</p></div></dd><dt><span class="term">
<span class="strong"><strong>cifsuser</strong></span>=<span class="emphasis"><em><username></em></span>
</span></dt><dd>
Set the cifs username, if not specified as part of the root.
</dd><dt><span class="term">
<span class="strong"><strong>cifspass</strong></span>=<span class="emphasis"><em><password></em></span>
</span></dt><dd><p class="simpara">
Set the cifs password, if not specified as part of the root.
</p><div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Warning</h3><p>Passwords specified on the kernel command line are visible for all
users via the file <span class="emphasis"><em>/proc/cmdline</em></span> and via dmesg or can be sniffed on the
network, when using DHCP with DHCP root-path.</p></div></dd></dl></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_iscsi"></a>iSCSI</h3></div></div></div><div class="variablelist"><dl class="variablelist"><dt><span class="term">
<span class="strong"><strong>root=</strong></span>iscsi:[<span class="emphasis"><em><username></em></span>:<span class="emphasis"><em><password></em></span>[:<span class="emphasis"><em><reverse></em></span>:<span class="emphasis"><em><password></em></span>]@][<span class="emphasis"><em><servername></em></span>]:[<span class="emphasis"><em><protocol></em></span>]:[<span class="emphasis"><em><port></em></span>][:[<span class="emphasis"><em><iscsi_iface_name></em></span>]:[<span class="emphasis"><em><netdev_name></em></span>]]:[<span class="emphasis"><em><LUN></em></span>]:<span class="emphasis"><em><targetname></em></span>
</span></dt><dd><p class="simpara">
protocol defaults to "6", LUN defaults to "0". If the "servername" field is
provided by BOOTP or DHCP, then that field is used in conjunction with other
associated fields to contact the boot server in the Boot stage. However, if
the "servername" field is not provided, then the "targetname" field is then
used in the Discovery Service stage in conjunction with other associated
fields. See
<a class="ulink" href="http://tools.ietf.org/html/rfc4173#section-5" target="_top">rfc4173</a>.
</p><div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Warning</h3><p>Passwords specified on the kernel command line are visible for all
users via the file <span class="emphasis"><em>/proc/cmdline</em></span> and via dmesg or can be sniffed on the
network, when using DHCP with DHCP root-path.</p></div><p><strong>Example. </strong>
</p><pre class="screen">root=iscsi:192.168.50.1::::iqn.2009-06.dracut:target0</pre><p>
</p><p class="simpara">If servername is an IPv6 address, it has to be put in brackets:</p><p><strong>Example. </strong>
</p><pre class="screen">root=iscsi:[2001:DB8::1]::::iqn.2009-06.dracut:target0</pre><p>
</p></dd><dt><span class="term">
<span class="strong"><strong>root=</strong></span><span class="emphasis"><em>???</em></span> <span class="strong"><strong>netroot=</strong></span>iscsi:[<span class="emphasis"><em><username></em></span>:<span class="emphasis"><em><password></em></span>[:<span class="emphasis"><em><reverse></em></span>:<span class="emphasis"><em><password></em></span>]@][<span class="emphasis"><em><servername></em></span>]:[<span class="emphasis"><em><protocol></em></span>]:[<span class="emphasis"><em><port></em></span>][:[<span class="emphasis"><em><iscsi_iface_name></em></span>]:[<span class="emphasis"><em><netdev_name></em></span>]]:[<span class="emphasis"><em><LUN></em></span>]:<span class="emphasis"><em><targetname></em></span> …
</span></dt><dd><p class="simpara">
multiple netroot options allow setting up multiple iscsi disks:
</p><p><strong>Example. </strong>
</p><pre class="screen">root=UUID=12424547
netroot=iscsi:192.168.50.1::::iqn.2009-06.dracut:target0
netroot=iscsi:192.168.50.1::::iqn.2009-06.dracut:target1</pre><p>
</p><p class="simpara">If servername is an IPv6 address, it has to be put in brackets:</p><p><strong>Example. </strong>
</p><pre class="screen">netroot=iscsi:[2001:DB8::1]::::iqn.2009-06.dracut:target0</pre><p>
</p><div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Warning</h3><p>Passwords specified on the kernel command line are visible for all
users via the file <span class="emphasis"><em>/proc/cmdline</em></span> and via dmesg or can be sniffed on the
network, when using DHCP with DHCP root-path.
You may want to use rd.iscsi.firmware.</p></div></dd><dt><span class="term">
<span class="strong"><strong>root=</strong></span><span class="emphasis"><em>???</em></span> <span class="strong"><strong>rd.iscsi.initiator=</strong></span><span class="emphasis"><em><initiator></em></span> <span class="strong"><strong>rd.iscsi.target.name=</strong></span><span class="emphasis"><em><target name></em></span> <span class="strong"><strong>rd.iscsi.target.ip=</strong></span><span class="emphasis"><em><target ip></em></span> <span class="strong"><strong>rd.iscsi.target.port=</strong></span><span class="emphasis"><em><target port></em></span> <span class="strong"><strong>rd.iscsi.target.group=</strong></span><span class="emphasis"><em><target group></em></span> <span class="strong"><strong>rd.iscsi.username=</strong></span><span class="emphasis"><em><username></em></span> <span class="strong"><strong>rd.iscsi.password=</strong></span><span class="emphasis"><em><password></em></span> <span class="strong"><strong>rd.iscsi.in.username=</strong></span><span class="emphasis"><em><in username></em></span> <span class="strong"><strong>rd.iscsi.in.password=</strong></span><span class="emphasis"><em><in password></em></span>
</span></dt><dd><p class="simpara">
manually specify all iscsistart parameter (see <span class="strong"><strong><code class="literal">iscsistart --help</code></strong></span>)
</p><div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Warning</h3><p>Passwords specified on the kernel command line are visible for all
users via the file <span class="emphasis"><em>/proc/cmdline</em></span> and via dmesg or can be sniffed on the
network, when using DHCP with DHCP root-path.
You may want to use rd.iscsi.firmware.</p></div></dd><dt><span class="term">
<span class="strong"><strong>root=</strong></span><span class="emphasis"><em>???</em></span> <span class="strong"><strong>netroot=</strong></span>iscsi <span class="strong"><strong>rd.iscsi.firmware=1</strong></span>
</span></dt><dd>
will read the iscsi parameter from the BIOS firmware
</dd><dt><span class="term">
<span class="strong"><strong>rd.iscsi.login_retry_max=</strong></span><span class="emphasis"><em><num></em></span>
</span></dt><dd>
maximum number of login retries
</dd><dt><span class="term">
<span class="strong"><strong>rd.iscsi.param=</strong></span><span class="emphasis"><em><param></em></span>
</span></dt><dd><p class="simpara">
<param> will be passed as "--param <param>" to iscsistart.
This parameter can be specified multiple times.
</p><p><strong>Example. </strong>
</p><pre class="screen">"netroot=iscsi rd.iscsi.firmware=1 rd.iscsi.param=node.session.timeo.replacement_timeout=30"</pre><p>
</p><p class="simpara">will result in</p><pre class="screen">iscsistart -b --param node.session.timeo.replacement_timeout=30</pre></dd></dl></div><p><span class="strong"><strong>rd.iscsi.ibft</strong></span> <span class="strong"><strong>rd.iscsi.ibft=1</strong></span>:
Turn on iBFT autoconfiguration for the interfaces</p><p><span class="strong"><strong>rd.iscsi.mp</strong></span> <span class="strong"><strong>rd.iscsi.mp=1</strong></span>:
Configure all iBFT interfaces, not only used for booting (multipath)</p><p><span class="strong"><strong>rd.iscsi.waitnet=0</strong></span>:
Turn off waiting for all interfaces to be up before trying to login to the iSCSI targets.</p><p><span class="strong"><strong>rd.iscsi.testroute=0</strong></span>:
Turn off checking, if the route to the iSCSI target IP is possible before trying to login.</p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_fcoe"></a>FCoE</h3></div></div></div><div class="variablelist"><dl class="variablelist"><dt><span class="term">
<span class="strong"><strong>rd.fcoe=0</strong></span>
</span></dt><dd>
disable FCoE and lldpad
</dd><dt><span class="term">
<span class="strong"><strong>fcoe=</strong></span><span class="emphasis"><em><edd|interface|MAC></em></span>:<span class="emphasis"><em>{dcb|nodcb}</em></span>:<span class="emphasis"><em>{fabric|vn2vn}</em></span>
</span></dt><dd><p class="simpara">
Try to connect to a FCoE SAN through the NIC specified by <span class="emphasis"><em><interface></em></span> or
<span class="emphasis"><em><MAC></em></span> or EDD settings. The second argument specifies if DCB
should be used. The optional third argument specifies whether
fabric or VN2VN mode should be used.
This parameter can be specified multiple times.
</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>letters in the MAC-address must be lowercase!</p></div></dd></dl></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_nvmf"></a>NVMf</h3></div></div></div><div class="variablelist"><dl class="variablelist"><dt><span class="term">
<span class="strong"><strong>rd.nonvmf=0</strong></span>
</span></dt><dd>
Disable NVMf
</dd><dt><span class="term">
<span class="strong"><strong>rd.nvmf.nonbft</strong></span>
</span></dt><dd>
Disable connecting to targets from the NVMe Boot Firmware Table. Without
this parameter, NBFT connections will take precedence over <span class="emphasis"><em>rd.nvmf.discover</em></span>.
</dd><dt><span class="term">
<span class="strong"><strong>rd.nvmf.nostatic</strong></span>
</span></dt><dd>
Disable connecting to targets that have been statically configured when
the initramfs was built. Targets specified with rd.nvmf.discover on the
kernel command line will still be tried.
</dd><dt><span class="term">
<span class="strong"><strong>rd.nvmf.hostnqn=</strong></span><span class="emphasis"><em><hostNQN></em></span>
</span></dt><dd>
NVMe host NQN to use
</dd><dt><span class="term">
<span class="strong"><strong>rd.nvmf.hostid=</strong></span><span class="emphasis"><em><hostID></em></span>
</span></dt><dd>
NVMe host id to use
</dd><dt><span class="term">
<span class="strong"><strong>rd.nvmf.discover=</strong></span><span class="emphasis"><em>{rdma|fc|tcp}</em></span>,<span class="emphasis"><em><traddr></em></span>,[<span class="emphasis"><em><host_traddr></em></span>],[<span class="emphasis"><em><trsvcid></em></span>]
</span></dt><dd>
Discover and connect to a NVMe-over-Fabric controller specified by
<span class="emphasis"><em><traddr></em></span> and the optionally <span class="emphasis"><em><host_traddr></em></span> or <span class="emphasis"><em><trsvcid></em></span>.
The first argument specifies the transport to use; currently only
<span class="emphasis"><em>rdma</em></span>, <span class="emphasis"><em>fc</em></span>, or <span class="emphasis"><em>tcp</em></span> are supported.
The <span class="emphasis"><em><traddr></em></span> parameter can be set to <span class="emphasis"><em>auto</em></span> to select
autodiscovery; in that case all other parameters are ignored.
This parameter can be specified multiple times.
</dd></dl></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_nbd"></a>NBD</h3></div></div></div><div class="variablelist"><dl class="variablelist"><dt><span class="term">
<span class="strong"><strong>root=</strong></span>??? <span class="strong"><strong>netroot=</strong></span>nbd:<span class="emphasis"><em><server></em></span>:<span class="emphasis"><em><port/exportname></em></span>[:<span class="emphasis"><em><fstype></em></span>[:<span class="emphasis"><em><mountopts></em></span>[:<span class="emphasis"><em><nbdopts></em></span>]]]
</span></dt><dd><p class="simpara">
mount nbd share from <server>.
</p><p class="simpara">NOTE:
If "exportname" instead of "port" is given the standard port is used.
Newer versions of nbd are only supported with "exportname".</p></dd><dt><span class="term">
<span class="strong"><strong>root=/dev/root netroot=dhcp</strong></span> with <span class="strong"><strong>dhcp</strong></span> <span class="strong"><strong>root-path=</strong></span>nbd:<span class="emphasis"><em><server></em></span>:<span class="emphasis"><em><port/exportname></em></span>[:<span class="emphasis"><em><fstype></em></span>[:<span class="emphasis"><em><mountopts></em></span>[:<span class="emphasis"><em><nbdopts></em></span>]]]
</span></dt><dd><p class="simpara">
netroot=dhcp alone directs initrd to look at the DHCP root-path where NBD
options can be specified. This syntax is only usable in cases where you are
directly mounting the volume as the rootfs.
</p><p class="simpara">NOTE:
If "exportname" instead of "port" is given the standard port is used.
Newer versions of nbd are only supported with "exportname".</p></dd></dl></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_virtiofs"></a>VIRTIOFS</h3></div></div></div><div class="variablelist"><dl class="variablelist"><dt><span class="term">
<span class="strong"><strong>root=</strong></span>virtiofs:<span class="emphasis"><em><mount-tag></em></span>
</span></dt><dd>
mount virtiofs share using the tag <mount-tag>.
The tag name is arbitrary and must match the tag given in the qemu <span class="emphasis"><em>-device</em></span> command.
</dd><dt><span class="term">
<span class="strong"><strong>rootfstype=</strong></span>virtiofs <span class="strong"><strong>root=</strong></span><span class="emphasis"><em><mount-tag></em></span>
</span></dt><dd>
mount virtiofs share using the tag <mount-tag>.
The tag name is arbitrary and must match the tag given in the qemu <span class="emphasis"><em>-device</em></span> command.
</dd></dl></div><p>Both formats are supported by the <span class="emphasis"><em>virtiofs</em></span> dracut module.
See <a class="ulink" href="https://gitlab.com/virtio-fs/virtiofsd" target="_top">https://gitlab.com/virtio-fs/virtiofsd</a> for more information.</p><p><strong>Example. </strong>
</p><pre class="screen">root=virtiofs:host rw</pre><p>
</p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_dasd"></a>DASD</h3></div></div></div><div class="variablelist"><dl class="variablelist"><dt><span class="term">
<span class="strong"><strong>rd.dasd=</strong></span>….
</span></dt><dd>
same syntax as the kernel module parameter (s390 only)
</dd></dl></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_zfcp"></a>ZFCP</h3></div></div></div><div class="variablelist"><dl class="variablelist"><dt><span class="term">
<span class="strong"><strong>rd.zfcp=</strong></span><span class="emphasis"><em><zfcp adaptor device bus ID></em></span>,<span class="emphasis"><em><WWPN></em></span>,<span class="emphasis"><em><FCPLUN></em></span>
</span></dt><dd>
rd.zfcp can be specified multiple times on the kernel command
line.
</dd><dt><span class="term">
<span class="strong"><strong>rd.zfcp=</strong></span><span class="emphasis"><em><zfcp adaptor device bus ID></em></span>
</span></dt><dd><p class="simpara">
If NPIV is enabled and the <span class="emphasis"><em>allow_lun_scan</em></span> parameter to the zfcp
module is set to <span class="emphasis"><em>Y</em></span> then the zfcp adaptor will be initiating a
scan internally and the <WWPN> and <FCPLUN> parameters can be omitted.
</p><p><strong>Example. </strong>
</p><pre class="screen">rd.zfcp=0.0.4000,0x5005076300C213e9,0x5022000000000000
rd.zfcp=0.0.4000</pre><p>
</p></dd><dt><span class="term">
<span class="strong"><strong>rd.zfcp.conf=0</strong></span>
</span></dt><dd>
ignore zfcp.conf included in the initramfs
</dd></dl></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_znet"></a>ZNET</h3></div></div></div><div class="variablelist"><dl class="variablelist"><dt><span class="term">
<span class="strong"><strong>rd.znet=</strong></span><span class="emphasis"><em><nettype></em></span>,<span class="emphasis"><em><subchannels></em></span>,<span class="emphasis"><em><options></em></span>
</span></dt><dd>
The whole parameter is appended to /etc/ccw.conf, which is used on
RHEL/Fedora with ccw_init, which is called from udev for certain
devices on z-series.
rd.znet can be specified multiple times on the kernel command line.
</dd><dt><span class="term">
<span class="strong"><strong>rd.znet_ifname=</strong></span><span class="emphasis"><em><ifname></em></span>:<span class="emphasis"><em><subchannels></em></span>
</span></dt><dd><p class="simpara">
Assign network device name <interface> (i.e. "bootnet") to the NIC
corresponds to the subchannels. This is useful when dracut’s default
"ifname=" doesn’t work due to device having a changing MAC address.
</p><p><strong>Example. </strong>
</p><pre class="screen">rd.znet=qeth,0.0.0600,0.0.0601,0.0.0602,layer2=1,portname=foo
rd.znet=ctc,0.0.0600,0.0.0601,protocol=bar</pre><p>
</p></dd></dl></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_booting_live_images"></a>Booting live images</h3></div></div></div><p>Dracut offers multiple options for live booted images:</p><div class="informalexample"><div class="variablelist"><dl class="variablelist"><dt><span class="term">
SquashFS with read-only filesystem image
</span></dt><dd><p class="simpara">
The system will boot with a
read-only filesystem from the SquashFS and apply a writable Device-mapper
snapshot or an OverlayFS overlay mount for the read-only base filesystem. This
method ensures a relatively fast boot and lower RAM usage. Users <span class="strong"><strong>must be
careful</strong></span> to avoid writing too many blocks to a snapshot volume. Once the
blocks of the snapshot overlay are exhausted, the root filesystem becomes
read-only and may cause application failures. The snapshot overlay file is
marked <span class="emphasis"><em>Overflow</em></span>, and a difficult recovery is required to repair and enlarge
the overlay offline. Non-persistent overlays are sparse files in RAM that only
consume content space as required blocks are allocated. They default to an
apparent size of 32 GiB in RAM. The size can be adjusted with the
<span class="strong"><strong>rd.live.overlay.size=</strong></span> kernel command line option.
</p><p class="simpara">The filesystem structure is traditionally expected to be:</p><pre class="screen">squashfs.img | SquashFS from LiveCD .iso
!(mount)
/LiveOS
|- rootfs.img | Filesystem image to mount read-only
!(mount)
/bin | Live filesystem
/boot |
/dev |
... |</pre><p class="simpara">For OverlayFS mount overlays, the filesystem structure may also be a direct
compression of the root filesystem:</p><pre class="screen">squashfs.img | SquashFS from LiveCD .iso
!(mount)
/bin | Live filesystem
/boot |
/dev |
... |</pre><p class="simpara">Dracut uses one of the overlay methods of live booting by default. No
additional command line options are required other than <span class="strong"><strong>root=live:<URL></strong></span> to
specify the location of your squashed filesystem.</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">
The compressed SquashFS image can be copied during boot to RAM at
<code class="literal">/run/initramfs/squashed.img</code> by using the <span class="strong"><strong>rd.live.ram=1</strong></span> option.
</li><li class="listitem">
A device with a persistent overlay can be booted read-only by using the
<span class="strong"><strong>rd.live.overlay.readonly</strong></span> option on the kernel command line. This will
either cause a temporary, writable overlay to be stacked over a read-only
snapshot of the root filesystem or the OverlayFS mount will use an additional
lower layer with the root filesystem.
</li></ul></div></dd><dt><span class="term">
Uncompressed live filesystem image
</span></dt><dd><p class="simpara">
When the live system was installed with the <span class="emphasis"><em>--skipcompress</em></span> option of the
<span class="emphasis"><em>livecd-iso-to-disk</em></span> installation script for Live USB devices, the root
filesystem image, <span class="emphasis"><em>rootfs.img</em></span>, is expanded on installation and no SquashFS
is involved during boot.
</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">
If <span class="strong"><strong>rd.live.ram=1</strong></span> is used in this situation, the full, uncompressed
root filesystem is copied during boot to <code class="literal">/run/initramfs/rootfs.img</code> in the
<code class="literal">/run</code> tmpfs.
</li><li class="listitem">
If <span class="strong"><strong>rd.live.overlay=none</strong></span> is provided as a kernel command line option,
a writable, linear Device-mapper target is created on boot with no overlay.
</li></ul></div></dd><dt><span class="term">
Writable filesystem image
</span></dt><dd><p class="simpara">
The system will retrieve a compressed filesystem image, extract it to
<code class="literal">/run/initramfs/fsimg/rootfs.img</code>, connect it to a loop device, create a
writable, linear Device-mapper target at <code class="literal">/dev/mapper/live-rw</code>, and mount that
as a writable volume at <code class="literal">/</code>. More RAM is required during boot but the live
filesystem is easier to manage if it becomes full. Users can make a filesystem
image of any size and that size will be maintained when the system boots. There
is no persistence of root filesystem changes between boots with this option.
</p><p class="simpara">The filesystem structure is expected to be:</p><pre class="screen">rootfs.tgz | Compressed tarball containing filesystem image
!(unpack)
/rootfs.img | Filesystem image at /run/initramfs/fsimg/
!(mount)
/bin | Live filesystem
/boot |
/dev |
... |</pre><p class="simpara">To use this boot option, ensure that <span class="strong"><strong>rd.writable.fsimg=1</strong></span> is in your kernel
command line and add the <span class="strong"><strong>root=live:<URL></strong></span> to specify the location
of your compressed filesystem image tarball or SquashFS image.</p></dd></dl></div></div><div class="variablelist"><dl class="variablelist"><dt><span class="term">
<span class="strong"><strong>rd.writable.fsimg=</strong></span>1
</span></dt><dd><p class="simpara">
Enables writable filesystem support. The system will boot with a fully
writable (but non-persistent) filesystem without snapshots <span class="emphasis"><em>(see notes above
about available live boot options)</em></span>. You can use the <span class="strong"><strong>rootflags</strong></span> option to
set mount options for the live filesystem as well <span class="emphasis"><em>(see documentation about
rootflags in the <span class="strong"><strong>Standard</strong></span> section above)</em></span>.
This implies that the whole image is copied to RAM before the boot continues.
</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>There must be enough free RAM available to hold the complete image.</p></div><p class="simpara">This method is very suitable for diskless boots.</p></dd><dt><span class="term">
<span class="strong"><strong>root=</strong></span>live:<span class="emphasis"><em><url></em></span>
</span></dt><dd><p class="simpara">
Boots a live image retrieved from <span class="emphasis"><em><url></em></span>. Requires the dracut <span class="emphasis"><em>livenet</em></span>
module. Valid handlers: <span class="emphasis"><em>http, https, ftp, torrent, tftp</em></span>.
</p><p><strong>Examples. </strong>
</p><pre class="screen">root=live:http://example.com/liveboot.img
root=live:ftp://ftp.example.com/liveboot.img
root=live:torrent://example.com/liveboot.img.torrent</pre><p>
</p></dd><dt><span class="term">
<span class="strong"><strong>rd.live.debug=</strong></span>1
</span></dt><dd>
Enables debug output from the live boot process.
</dd><dt><span class="term">
<span class="strong"><strong>rd.live.dir=</strong></span><span class="emphasis"><em><path></em></span>
</span></dt><dd>
Specifies the directory within the boot device where the squashfs.img or
rootfs.img can be found. By default, this is <code class="literal">/LiveOS</code>.
</dd><dt><span class="term">
<span class="strong"><strong>rd.live.squashimg=</strong></span><span class="emphasis"><em><filename of SquashFS image></em></span>
</span></dt><dd>
Specifies the filename for a SquashFS image of the root filesystem.
By default, this is <span class="emphasis"><em>squashfs.img</em></span>.
</dd><dt><span class="term">
<span class="strong"><strong>rd.live.ram=</strong></span>1
</span></dt><dd>
Copy the complete image to RAM and use this for booting. This is useful
when the image resides on, e.g., a DVD which needs to be ejected later on.
</dd><dt><span class="term">
<span class="strong"><strong>rd.live.overlay={</strong></span><span class="emphasis"><em><devspec></em></span>[:<span class="emphasis"><em>{<pathspec>|auto}</em></span>]|<span class="emphasis"><em>none</em></span>}
</span></dt><dd><p class="simpara">
Manage the usage of a permanent overlay.
</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">
<span class="emphasis"><em><devspec></em></span> specifies the path to a device with a mountable filesystem.
</li><li class="listitem"><p class="simpara">
<span class="emphasis"><em><pathspec></em></span> is the path to a file within that filesystem, which shall be
used to persist the changes made to the device specified by the
<span class="strong"><strong>root=live:<span class="emphasis"><em><url></em></span></strong></span> option.
</p><p class="simpara">The default <span class="emphasis"><em>pathspec</em></span>, when <span class="emphasis"><em>auto</em></span> or no <span class="emphasis"><em>:<pathspec></em></span> is given, is
<code class="literal">/<rd.live.dir>/overlay-<label>-<uuid></code>, where <span class="emphasis"><em><label></em></span> is the
device LABEL, and <span class="emphasis"><em><uuid></em></span> is the device UUID.
* <span class="emphasis"><em>none</em></span> (the word itself) specifies that no overlay will be used, such as when
an uncompressed, writable live root filesystem is available.</p><p class="simpara">If a persistent overlay <span class="emphasis"><em>is detected</em></span> at the standard LiveOS path, the
overlay & overlay type detected, whether Device-mapper or OverlayFS, will be
used.</p></li></ul></div><p><strong>Examples. </strong>
</p><pre class="screen">rd.live.overlay=/dev/sdb1:persistent-overlay.img
rd.live.overlay=UUID=99440c1f-8daa-41bf-b965-b7240a8996f4</pre><p>
</p></dd><dt><span class="term">
<span class="strong"><strong>rd.live.overlay.cowfs=</strong></span><span class="emphasis"><em>[btrfs|ext4|xfs]</em></span>
</span></dt><dd>
Specifies the filesystem to use when formatting the overlay partition.
The default is ext4.
</dd><dt><span class="term">
<span class="strong"><strong>rd.live.overlay.size=</strong></span><span class="emphasis"><em><size_MiB></em></span>
</span></dt><dd>
Specifies a non-persistent Device-mapper overlay size in MiB. The default is
<span class="emphasis"><em>32768</em></span>.
</dd><dt><span class="term">
<span class="strong"><strong>rd.live.overlay.readonly=</strong></span>1
</span></dt><dd>
This is used to boot with a normally read-write persistent overlay in a
read-only mode. With this option, either an additional, non-persistent,
writable snapshot overlay will be stacked over a read-only snapshot,
<code class="literal">/dev/mapper/live‑ro</code>, of the base filesystem with the persistent overlay, or a
read-only loop device, in the case of a writable <span class="emphasis"><em>rootfs.img</em></span>, or an OverlayFS
mount will use the persistent overlay directory linked at <code class="literal">/run/overlayfs‑r</code> as
an additional lower layer along with the base root filesystem and apply a
transient, writable upper directory overlay, in order to complete the booted
root filesystem.
</dd><dt><span class="term">
<span class="strong"><strong>rd.live.overlay.reset=</strong></span>1
</span></dt><dd>
Specifies that a persistent overlay should be reset on boot. All previous root
filesystem changes are vacated by this action.
</dd><dt><span class="term">
<span class="strong"><strong>rd.live.overlay.thin=</strong></span>1
</span></dt><dd>
Enables the usage of thin snapshots instead of classic dm snapshots.
The advantage of thin snapshots is that they support discards, and will free
blocks that are not claimed by the filesystem. In this use case, this means
that memory is given back to the kernel when the filesystem does not claim it
anymore.
</dd><dt><span class="term">
<span class="strong"><strong>rd.live.overlay.overlayfs=</strong></span>1
</span></dt><dd><p class="simpara">
Enables the use of the <span class="strong"><strong>OverlayFS</strong></span> kernel module, if available, to provide a
copy-on-write union directory for the root filesystem. OverlayFS overlays are
directories of the files that have changed on the read-only base (lower)
filesystem. The root filesystem is provided through a special overlay type
mount that merges the lower and upper directories. If an OverlayFS upper
directory is not present on the boot device, a tmpfs directory will be created
at <code class="literal">/run/overlayfs</code> to provide temporary storage. Persistent storage can be
provided on vfat or msdos formatted devices by supplying the OverlayFS upper
directory within an embedded filesystem that supports the creation of trusted.*
extended attributes and provides a valid d_type in readdir responses, such as
with ext4 and xfs. On non-vfat-formatted devices, a persistent OverlayFS
overlay can extend the available root filesystem storage up to the capacity of
the LiveOS disk device.
</p><p class="simpara">If a persistent overlay is detected at the standard LiveOS path, the overlay &
overlay type detected, whether OverlayFS or Device-mapper, will be used.</p><p class="simpara">The <span class="strong"><strong>rd.live.overlay.readonly</strong></span> option, which allows a persistent overlayfs to
be mounted read-only through a higher level transient overlay directory, has
been implemented through the multiple lower layers feature of OverlayFS.</p></dd></dl></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_zipl"></a>ZIPL</h3></div></div></div><div class="variablelist"><dl class="variablelist"><dt><span class="term">
<span class="strong"><strong>rd.zipl=</strong></span><span class="emphasis"><em><path to blockdevice></em></span>
</span></dt><dd><p class="simpara">
Update the dracut commandline with the values found in the
<span class="emphasis"><em>dracut-cmdline.conf</em></span> file on the given device.
The values are merged into the existing commandline values
and the udev events are regenerated.
</p><p><strong>Example. </strong>
</p><pre class="screen">rd.zipl=UUID=0fb28157-99e3-4395-adef-da3f7d44835a</pre><p>
</p></dd></dl></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_cio_ignore"></a>CIO_IGNORE</h3></div></div></div><div class="variablelist"><dl class="variablelist"><dt><span class="term">
<span class="strong"><strong>rd.cio_accept=</strong></span><span class="emphasis"><em><device-ids></em></span>
</span></dt><dd><p class="simpara">
Remove the devices listed in <device-ids> from the default
cio_ignore kernel command-line settings.
<device-ids> is a list of comma-separated CCW device ids.
The default for this value is taken from the
<span class="emphasis"><em>/boot/zipl/active_devices.txt</em></span> file.
</p><p><strong>Example. </strong>
</p><pre class="screen">rd.cio_accept=0.0.0180,0.0.0800,0.0.0801,0.0.0802</pre><p>
</p></dd></dl></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_plymouth_boot_splash"></a>Plymouth Boot Splash</h3></div></div></div><div class="variablelist"><dl class="variablelist"><dt><span class="term">
<span class="strong"><strong>plymouth.enable=0</strong></span>
</span></dt><dd>
disable the plymouth bootsplash completely.
</dd><dt><span class="term">
<span class="strong"><strong>rd.plymouth=0</strong></span>
</span></dt><dd>
disable the plymouth bootsplash only for the initramfs.
</dd></dl></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_kernel_keys"></a>Kernel keys</h3></div></div></div><div class="variablelist"><dl class="variablelist"><dt><span class="term">
<span class="strong"><strong>masterkey=</strong></span><span class="emphasis"><em><kernel master key path name></em></span>
</span></dt><dd><p class="simpara">
Set the path name of the kernel master key.
</p><p><strong>Example. </strong>
</p><pre class="screen">masterkey=/etc/keys/kmk-trusted.blob</pre><p>
</p></dd><dt><span class="term">
<span class="strong"><strong>masterkeytype=</strong></span><span class="emphasis"><em><kernel master key type></em></span>
</span></dt><dd><p class="simpara">
Set the type of the kernel master key.
</p><p><strong>Example. </strong>
</p><pre class="screen">masterkeytype=trusted</pre><p>
</p></dd><dt><span class="term">
<span class="strong"><strong>evmkey=</strong></span><span class="emphasis"><em><EVM HMAC key path name></em></span>
</span></dt><dd><p class="simpara">
Set the path name of the EVM HMAC key.
</p><p><strong>Example. </strong>
</p><pre class="screen">evmkey=/etc/keys/evm-trusted.blob</pre><p>
</p></dd><dt><span class="term">
<span class="strong"><strong>evmx509=</strong></span><span class="emphasis"><em><EVM X.509 cert path name></em></span>
</span></dt><dd><p class="simpara">
Set the path name of the EVM X.509 certificate.
</p><p><strong>Example. </strong>
</p><pre class="screen">evmx509=/etc/keys/x509_evm.der</pre><p>
</p></dd><dt><span class="term">
<span class="strong"><strong>ecryptfskey=</strong></span><span class="emphasis"><em><eCryptfs key path name></em></span>
</span></dt><dd><p class="simpara">
Set the path name of the eCryptfs key.
</p><p><strong>Example. </strong>
</p><pre class="screen">ecryptfskey=/etc/keys/ecryptfs-trusted.blob</pre><p>
</p></dd></dl></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_deprecated_renamed_options"></a>Deprecated, renamed Options</h3></div></div></div><p>Here is a list of options, which were used in dracut prior to version 008, and
their new replacement.</p><div class="variablelist"><dl class="variablelist"><dt><span class="term">
rdbreak
</span></dt><dd>
rd.break
</dd><dt><span class="term">
rd.ccw
</span></dt><dd>
rd.znet
</dd><dt><span class="term">
rd_CCW
</span></dt><dd>
rd.znet
</dd><dt><span class="term">
rd_DASD_MOD
</span></dt><dd>
rd.dasd
</dd><dt><span class="term">
rd_DASD
</span></dt><dd>
rd.dasd
</dd><dt><span class="term">
rdinitdebug rdnetdebug
</span></dt><dd>
rd.debug
</dd><dt><span class="term">
rd_NO_DM
</span></dt><dd>
rd.dm=0
</dd><dt><span class="term">
rd_DM_UUID
</span></dt><dd>
rd.dm.uuid
</dd><dt><span class="term">
rdblacklist
</span></dt><dd>
rd.driver.blacklist
</dd><dt><span class="term">
rdinsmodpost
</span></dt><dd>
rd.driver.post
</dd><dt><span class="term">
rdloaddriver
</span></dt><dd>
rd.driver.pre
</dd><dt><span class="term">
rd_NO_FSTAB
</span></dt><dd>
rd.fstab=0
</dd><dt><span class="term">
rdinfo
</span></dt><dd>
rd.info
</dd><dt><span class="term">
check
</span></dt><dd>
rd.live.check
</dd><dt><span class="term">
rdlivedebug
</span></dt><dd>
rd.live.debug
</dd><dt><span class="term">
live_dir
</span></dt><dd>
rd.live.dir
</dd><dt><span class="term">
liveimg
</span></dt><dd>
rd.live.image
</dd><dt><span class="term">
overlay
</span></dt><dd>
rd.live.overlay
</dd><dt><span class="term">
readonly_overlay
</span></dt><dd>
rd.live.overlay.readonly
</dd><dt><span class="term">
reset_overlay
</span></dt><dd>
rd.live.overlay.reset
</dd><dt><span class="term">
live_ram
</span></dt><dd>
rd.live.ram
</dd><dt><span class="term">
rd_NO_CRYPTTAB
</span></dt><dd>
rd.luks.crypttab=0
</dd><dt><span class="term">
rd_LUKS_KEYDEV_UUID
</span></dt><dd>
rd.luks.keydev.uuid
</dd><dt><span class="term">
rd_LUKS_KEYPATH
</span></dt><dd>
rd.luks.keypath
</dd><dt><span class="term">
rd_NO_LUKS
</span></dt><dd>
rd.luks=0
</dd><dt><span class="term">
rd_LUKS_UUID
</span></dt><dd>
rd.luks.uuid
</dd><dt><span class="term">
rd_NO_LVMCONF
</span></dt><dd>
rd.lvm.conf
</dd><dt><span class="term">
rd_LVM_LV
</span></dt><dd>
rd.lvm.lv
</dd><dt><span class="term">
rd_NO_LVM
</span></dt><dd>
rd.lvm=0
</dd><dt><span class="term">
rd_LVM_SNAPSHOT
</span></dt><dd>
rd.lvm.snapshot
</dd><dt><span class="term">
rd_LVM_SNAPSIZE
</span></dt><dd>
rd.lvm.snapsize
</dd><dt><span class="term">
rd_LVM_VG
</span></dt><dd>
rd.lvm.vg
</dd><dt><span class="term">
rd_NO_MDADMCONF
</span></dt><dd>
rd.md.conf=0
</dd><dt><span class="term">
rd_NO_MDIMSM
</span></dt><dd>
rd.md.imsm=0
</dd><dt><span class="term">
rd_NO_MD
</span></dt><dd>
rd.md=0
</dd><dt><span class="term">
rd_MD_UUID
</span></dt><dd>
rd.md.uuid
</dd></dl></div><p>rd_NO_MULTIPATH: rd.multipath=0</p><div class="variablelist"><dl class="variablelist"><dt><span class="term">
rd_NFS_DOMAIN
</span></dt><dd>
rd.nfs.domain
</dd><dt><span class="term">
iscsi_initiator
</span></dt><dd>
rd.iscsi.initiator
</dd><dt><span class="term">
iscsi_target_name
</span></dt><dd>
rd.iscsi.target.name
</dd><dt><span class="term">
iscsi_target_ip
</span></dt><dd>
rd.iscsi.target.ip
</dd><dt><span class="term">
iscsi_target_port
</span></dt><dd>
rd.iscsi.target.port
</dd><dt><span class="term">
iscsi_target_group
</span></dt><dd>
rd.iscsi.target.group
</dd><dt><span class="term">
iscsi_username
</span></dt><dd>
rd.iscsi.username
</dd><dt><span class="term">
iscsi_password
</span></dt><dd>
rd.iscsi.password
</dd><dt><span class="term">
iscsi_in_username
</span></dt><dd>
rd.iscsi.in.username
</dd><dt><span class="term">
iscsi_in_password
</span></dt><dd>
rd.iscsi.in.password
</dd><dt><span class="term">
iscsi_firmware
</span></dt><dd>
rd.iscsi.firmware=0
</dd><dt><span class="term">
rd_NO_PLYMOUTH
</span></dt><dd>
rd.plymouth=0
</dd><dt><span class="term">
rd_retry
</span></dt><dd>
rd.retry
</dd><dt><span class="term">
rdshell
</span></dt><dd>
rd.shell
</dd><dt><span class="term">
rd_NO_SPLASH
</span></dt><dd>
rd.splash
</dd><dt><span class="term">
rdudevdebug
</span></dt><dd>
rd.udev.debug
</dd><dt><span class="term">
rdudevinfo
</span></dt><dd>
rd.udev.info
</dd><dt><span class="term">
rd_NO_ZFCPCONF
</span></dt><dd>
rd.zfcp.conf=0
</dd><dt><span class="term">
rd_ZFCP
</span></dt><dd>
rd.zfcp
</dd><dt><span class="term">
rd_ZNET
</span></dt><dd>
rd.znet
</dd><dt><span class="term">
KEYMAP
</span></dt><dd>
vconsole.keymap
</dd><dt><span class="term">
KEYTABLE
</span></dt><dd>
vconsole.keymap
</dd><dt><span class="term">
SYSFONT
</span></dt><dd>
vconsole.font
</dd><dt><span class="term">
CONTRANS
</span></dt><dd>
vconsole.font.map
</dd><dt><span class="term">
UNIMAP
</span></dt><dd>
vconsole.font.unimap
</dd><dt><span class="term">
UNICODE
</span></dt><dd>
vconsole.unicode
</dd><dt><span class="term">
EXT_KEYMAP
</span></dt><dd>
vconsole.keymap.ext
</dd></dl></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_configuration_in_the_initramfs_2"></a>Configuration in the Initramfs</h3></div></div></div><div class="variablelist"><dl class="variablelist"><dt><span class="term">
<span class="emphasis"><em>/etc/conf.d/</em></span>
</span></dt><dd>
Any files found in <span class="emphasis"><em>/etc/conf.d/</em></span> will be sourced in the initramfs to
set initial values. Command line options will override these values
set in the configuration files.
</dd><dt><span class="term">
<span class="emphasis"><em>/etc/cmdline</em></span>
</span></dt><dd>
Can contain additional command line options. Deprecated, better use
/etc/cmdline.d/*.conf.
</dd><dt><span class="term">
<span class="emphasis"><em>/etc/cmdline.d/*.conf</em></span>
</span></dt><dd>
Can contain additional command line options.
</dd></dl></div></div></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="_author_2"></a>AUTHOR</h2></div></div></div><p>Harald Hoyer</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="_see_also_3"></a>SEE ALSO</h2></div></div></div><p><span class="strong"><strong>dracut</strong></span>(8) <span class="strong"><strong>dracut.conf</strong></span>(5)</p></div></div><div class="chapter"><div class="titlepage"><div><div><h2 class="title"><a id="lsinitrd1"></a>Chapter 9. LSINITRD(1)</h2></div></div></div><div class="toc"><p><strong>Table of Contents</strong></p><dl class="toc"><dt><span class="section"><a href="#_name_4">NAME</a></span></dt><dt><span class="section"><a href="#_synopsis_3">SYNOPSIS</a></span></dt><dt><span class="section"><a href="#_description_4">DESCRIPTION</a></span></dt><dt><span class="section"><a href="#_options_2">OPTIONS</a></span></dt><dt><span class="section"><a href="#_availability_2">AVAILABILITY</a></span></dt><dt><span class="section"><a href="#_authors_2">AUTHORS</a></span></dt><dt><span class="section"><a href="#_see_also_4">SEE ALSO</a></span></dt></dl></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="_name_4"></a>NAME</h2></div></div></div><p>lsinitrd - tool to show the contents of an initramfs image</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="_synopsis_3"></a>SYNOPSIS</h2></div></div></div><p><span class="strong"><strong>lsinitrd</strong></span> [<span class="emphasis"><em>OPTION…</em></span>] [<image> [<filename> [<filename> […] ]]]</p><p><span class="strong"><strong>lsinitrd</strong></span> [<span class="emphasis"><em>OPTION…</em></span>] -k <kernel version></p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="_description_4"></a>DESCRIPTION</h2></div></div></div><p>lsinitrd shows the contents of an initramfs image. if <image> is omitted, then
lsinitrd uses the default image <span class="emphasis"><em>/efi/<machine-id>/<kernel-version>/initrd</em></span>,
<span class="emphasis"><em>/boot/<machine-id>/<kernel-version>/initrd</em></span>,
<span class="emphasis"><em>/boot/efi/<machine-id>/<kernel-version>/initrd</em></span>,
<span class="emphasis"><em>/lib/modules/<kernel-version>/initrd</em></span> or
<span class="emphasis"><em>/boot/initramfs-<kernel-version>.img</em></span>.</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="_options_2"></a>OPTIONS</h2></div></div></div><div class="variablelist"><dl class="variablelist"><dt><span class="term">
<span class="strong"><strong>-h, --help</strong></span>
</span></dt><dd>
print a help message and exit.
</dd><dt><span class="term">
<span class="strong"><strong>-s, --size</strong></span>
</span></dt><dd>
sort the contents of the initramfs by size.
</dd><dt><span class="term">
<span class="strong"><strong>-f, --file</strong></span> <span class="emphasis"><em><filename></em></span>
</span></dt><dd>
print the contents of <filename>.
</dd><dt><span class="term">
<span class="strong"><strong>-k, --kver</strong></span> <span class="emphasis"><em><kernel version></em></span>
</span></dt><dd>
inspect the initramfs of <kernel version>.
</dd><dt><span class="term">
<span class="strong"><strong>-m, --mod</strong></span>
</span></dt><dd>
list dracut modules included of the initramfs image.
</dd><dt><span class="term">
<span class="strong"><strong>--unpack</strong></span>
</span></dt><dd>
unpack the initramfs to the current directory, instead of displaying the contents.
If optional filenames are given, will only unpack specified files, else the whole image will be unpacked.
Won’t unpack anything from early cpio part.
</dd><dt><span class="term">
<span class="strong"><strong>--unpackearly</strong></span>
</span></dt><dd>
unpack the early microcode initramfs to the current directory, instead of displaying the contents.
Same as --unpack, but only unpack files from early cpio part.
</dd><dt><span class="term">
<span class="strong"><strong>-v, --verbose</strong></span>
</span></dt><dd>
unpack verbosely
</dd></dl></div></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="_availability_2"></a>AVAILABILITY</h2></div></div></div><p>The lsinitrd command is part of the dracut package and is available from
<a class="ulink" href="https://dracut.wiki.kernel.org" target="_top">https://dracut.wiki.kernel.org</a></p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="_authors_2"></a>AUTHORS</h2></div></div></div><p>Harald Hoyer</p><p>Amerigo Wang</p><p>Nikoli</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="_see_also_4"></a>SEE ALSO</h2></div></div></div><p><span class="strong"><strong>dracut</strong></span>(8)</p></div></div><div class="chapter"><div class="titlepage"><div><div><h2 class="title"><a id="_developer_manual"></a>Chapter 10. Developer Manual</h2></div></div></div></div><div class="chapter"><div class="titlepage"><div><div><h2 class="title"><a id="dracutmodules7"></a>Chapter 11. DRACUT.MODULES(7)</h2></div></div></div><div class="toc"><p><strong>Table of Contents</strong></p><dl class="toc"><dt><span class="section"><a href="#_name_5">NAME</a></span></dt><dt><span class="section"><a href="#_description_5">DESCRIPTION</a></span></dt><dt><span class="section"><a href="#stages">Boot Process Stages</a></span></dt><dd><dl><dt><span class="section"><a href="#_hook_cmdline">Hook: cmdline</a></span></dt><dt><span class="section"><a href="#_hook_pre_udev">Hook: pre-udev</a></span></dt><dt><span class="section"><a href="#_start_udev">Start Udev</a></span></dt><dt><span class="section"><a href="#_hook_pre_trigger">Hook: pre-trigger</a></span></dt><dt><span class="section"><a href="#_trigger_udev">Trigger Udev</a></span></dt><dt><span class="section"><a href="#_main_loop">Main Loop</a></span></dt><dt><span class="section"><a href="#_hook_pre_mount">Hook: pre-mount</a></span></dt><dt><span class="section"><a href="#_hook_mount">Hook: mount</a></span></dt><dt><span class="section"><a href="#_hook_pre_pivot">Hook: pre-pivot</a></span></dt><dt><span class="section"><a href="#_hook_cleanup">Hook: cleanup</a></span></dt><dt><span class="section"><a href="#_cleanup_and_switch_root">Cleanup and switch_root</a></span></dt></dl></dd><dt><span class="section"><a href="#_network_infrastructure">Network Infrastructure</a></span></dt><dt><span class="section"><a href="#_writing_a_module">Writing a Module</a></span></dt><dd><dl><dt><span class="section"><a href="#_module_setup_sh_check">module-setup.sh: check()</a></span></dt><dt><span class="section"><a href="#_module_setup_sh_depends">module-setup.sh: depends()</a></span></dt><dt><span class="section"><a href="#_module_setup_sh_cmdline">module-setup.sh: cmdline()</a></span></dt><dt><span class="section"><a href="#_module_setup_sh_install">module-setup.sh: install()</a></span></dt><dt><span class="section"><a href="#_module_setup_sh_installkernel">module-setup.sh: installkernel()</a></span></dt><dt><span class="section"><a href="#_anchor_id_creation_xreflabel_creation_creation_functions">Creation Functions</a></span></dt><dt><span class="section"><a href="#_initramfs_functions">Initramfs Functions</a></span></dt><dt><span class="section"><a href="#_network_modules">Network Modules</a></span></dt></dl></dd><dt><span class="section"><a href="#_author_3">AUTHOR</a></span></dt><dt><span class="section"><a href="#_see_also_5">SEE ALSO</a></span></dt></dl></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="_name_5"></a>NAME</h2></div></div></div><p>dracut.modules - dracut modules</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="_description_5"></a>DESCRIPTION</h2></div></div></div><p>dracut uses a modular system to build and extend the initramfs image. All
modules are located in <span class="emphasis"><em>/usr/lib/dracut/modules.d</em></span> or in <span class="emphasis"><em><git-src>/modules.d</em></span>.
The most basic dracut module is <span class="emphasis"><em>99base</em></span>. In <span class="emphasis"><em>99base</em></span> the initial shell script
init is defined, which gets run by the kernel after initramfs loading. Although
you can replace init with your own version of <span class="emphasis"><em>99base</em></span>, this is not encouraged.
Instead you should use, if possible, the hooks of dracut. All hooks, and the
point of time in which they are executed, are described in <a class="xref" href="#stages" title="Boot Process Stages">the section called “Boot Process Stages”</a>.</p><p>The main script, which creates the initramfs is dracut itself. It parses all
arguments and sets up the directory, in which everything is installed. It then
executes all check, install, installkernel scripts found in the modules, which
are to be processed. After everything is installed, the install directory is
archived and compressed to the final initramfs image. All helper functions used
by check, install and installkernel are found in in the file <span class="emphasis"><em>dracut-functions</em></span>.
These shell functions are available to all module installer (install,
installkernel) scripts, without the need to source <span class="emphasis"><em>dracut-functions</em></span>.</p><p>A module can check the preconditions for install and installkernel with the
check script. Also dependencies can be expressed with check. If a module passed
check, install and installkernel will be called to install all of the necessary
files for the module. To split between kernel and non-kernel parts of the
installation, all kernel module related parts have to be in installkernel. All
other files found in a module directory are module specific and mostly are hook
scripts and udev rules.</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="stages"></a>Boot Process Stages</h2></div></div></div><p>dracut modules can insert custom script at various points, to control the boot
process.
These hooks are plain directories containing shell scripts ending with ".sh",
which are sourced by init.
Common used functions are in <span class="emphasis"><em>dracut-lib.sh</em></span>, which can be sourced by any script.</p><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_hook_cmdline"></a>Hook: cmdline</h3></div></div></div><p>The <span class="emphasis"><em>cmdline</em></span> hook is a place to insert scripts to parse the kernel command line
and prepare the later actions, like setting up udev rules and configuration
files.</p><p>In this hook the most important environment variable is defined: root. The
second one is rootok, which indicates, that a module claimed to be able to parse
the root defined. So for example, <span class="strong"><strong>root=</strong></span><span class="emphasis"><em>iscsi:….</em></span> will be claimed by the
iscsi dracut module, which then sets rootok.</p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_hook_pre_udev"></a>Hook: pre-udev</h3></div></div></div><p>This hook is executed right after the cmdline hook and a check if root and
rootok were set. Here modules can take action with the final root, and before
udev has been run.</p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_start_udev"></a>Start Udev</h3></div></div></div><p>Now udev is started and the logging for udev is setup.</p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_hook_pre_trigger"></a>Hook: pre-trigger</h3></div></div></div><p>In this hook, you can set udev environment variables with <span class="strong"><strong>udevadm control
--property=KEY=<span class="emphasis"><em>value</em></span></strong></span> or control the further execution of udev with
udevadm.</p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_trigger_udev"></a>Trigger Udev</h3></div></div></div><p>udev is triggered by calling udevadm trigger, which sends add events for all
devices and subsystems.</p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_main_loop"></a>Main Loop</h3></div></div></div><p>In the main loop of dracut loops until udev has settled and
all scripts in <span class="emphasis"><em>initqueue/finished</em></span> returned true.
In this loop there are three hooks, where scripts can be inserted
by calling /sbin/initqueue.</p><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="_initqueue"></a>Initqueue</h4></div></div></div><p>This hook gets executed every time a script is inserted here, regardless of the
udev state.</p></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="_initqueue_settled"></a>Initqueue settled</h4></div></div></div><p>This hook (initqueue/settled) gets executed every time udev has settled.</p></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="_initqueue_timeout"></a>Initqueue timeout</h4></div></div></div><p>This hook (initqueue/timeout) gets executed, when the main loop counter becomes
half of the rd.retry counter.</p></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="_initqueue_online"></a>Initqueue online</h4></div></div></div><p>This hook (initqueue/online) gets executed whenever a network interface comes online
(that is, once it is up and configured by the configured network module).</p></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="_initqueue_finished"></a>Initqueue finished</h4></div></div></div><p>This hook (initqueue/finished) is called after udev has settled and
if all scripts herein return 0 the main loop will be ended.
Arbitrary scripts can be added here, to loop in the
initqueue until something happens, which a dracut module wants to wait for.</p></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_hook_pre_mount"></a>Hook: pre-mount</h3></div></div></div><p>Before the root device is mounted all scripts in the hook pre-mount are
executed. In some cases (e.g. NFS) the real root device is already mounted,
though.</p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_hook_mount"></a>Hook: mount</h3></div></div></div><p>This hook is mainly to mount the real root device.</p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_hook_pre_pivot"></a>Hook: pre-pivot</h3></div></div></div><p>This hook is called before cleanup hook, This is a good place for
actions other than cleanups which need to be called before pivot.</p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_hook_cleanup"></a>Hook: cleanup</h3></div></div></div><p>This hook is the last hook and is called before init finally switches root to
the real root device. This is a good place to clean up and kill processes not
needed anymore.</p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_cleanup_and_switch_root"></a>Cleanup and switch_root</h3></div></div></div><p>Init (or systemd) kills all udev processes, cleans up the environment,
sets up the arguments for the real init process and finally calls switch_root.
switch_root removes the whole filesystem hierarchy of the initramfs,
chroot()s to the real root device and calls /sbin/init with the specified
arguments.</p><p>To ensure all files in the initramfs hierarchy can be removed, all processes
still running from the initramfs should not have any open file descriptors left.</p></div></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="_network_infrastructure"></a>Network Infrastructure</h2></div></div></div><p>FIXME</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="_writing_a_module"></a>Writing a Module</h2></div></div></div><p>A simple example module is <span class="emphasis"><em>90kernel-modules</em></span>, which modprobes a kernel module
after udev has settled and the basic device drivers have been loaded.</p><p>All module installation information is in the file module-setup.sh.</p><p>First we create a check() function, which just exits with 0 indicating that this
module should be included by default.</p><p>check():</p><pre class="screen">return 0</pre><p>Then we create the install() function, which installs a cmdline hook with
priority number 20 called <span class="emphasis"><em>parse-insmodpost.sh</em></span>. It also installs the
<span class="emphasis"><em>insmodpost.sh</em></span> script in <span class="emphasis"><em>/sbin</em></span>.</p><p>install():</p><pre class="screen">inst_hook cmdline 20 "$moddir/parse-insmodpost.sh"
inst_simple "$moddir/insmodpost.sh" /sbin/insmodpost.sh</pre><p>The <span class="emphasis"><em>parse-instmodpost.sh</em></span> parses the kernel command line for a argument
rd.driver.post, blacklists the module from being autoloaded and installs the
hook <span class="emphasis"><em>insmodpost.sh</em></span> in the <span class="emphasis"><em>initqueue/settled</em></span>.</p><p><span class="emphasis"><em>parse-insmodpost.sh</em></span>:</p><pre class="screen">for p in $(getargs rd.driver.post=); do
echo "blacklist $p" >> /etc/modprobe.d/initramfsblacklist.conf
_do_insmodpost=1
done
[ -n "$_do_insmodpost" ] && /sbin/initqueue --settled --unique --onetime /sbin/insmodpost.sh
unset _do_insmodpost</pre><p><span class="emphasis"><em>insmodpost.sh</em></span>, which is called in the <span class="emphasis"><em>initqueue/settled</em></span> hook will just
modprobe the kernel modules specified in all rd.driver.post kernel command line
parameters. It runs after udev has settled and is only called once (--onetime).</p><p><span class="emphasis"><em>insmodpost.sh</em></span>:</p><pre class="screen">. /lib/dracut-lib.sh
for p in $(getargs rd.driver.post=); do
modprobe $p
done</pre><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_module_setup_sh_check"></a>module-setup.sh: check()</h3></div></div></div><p><span class="emphasis"><em>check()</em></span> is called by dracut to evaluate the inclusion of a dracut module in
the initramfs.</p><div class="variablelist"><dl class="variablelist"><dt><span class="term">
$hostonly
</span></dt><dd>
If the $hostonly variable is set, then the module check() function
should be in "hostonly" mode, which means, that the check() should only return
0, if the module is really needed to boot this specific host.
</dd></dl></div><p>check() should return with:</p><div class="variablelist"><dl class="variablelist"><dt><span class="term">
0
</span></dt><dd>
Include the dracut module in the initramfs.
</dd><dt><span class="term">
1
</span></dt><dd>
Do not include the dracut module. The requirements are not fulfilled
(missing tools, etc.)
</dd><dt><span class="term">
255
</span></dt><dd>
Only include the dracut module, if another module requires it or if
explicitly specified in the config file or on the argument list.
</dd></dl></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_module_setup_sh_depends"></a>module-setup.sh: depends()</h3></div></div></div><p>The function depends() should echo all other dracut module names the module
depends on.</p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_module_setup_sh_cmdline"></a>module-setup.sh: cmdline()</h3></div></div></div><p>This function should print the kernel command line options needed to boot the
current machine setup. It should start with a space and should not print a
newline.</p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_module_setup_sh_install"></a>module-setup.sh: install()</h3></div></div></div><p>The install() function is called to install everything non-kernel related.
To install binaries, scripts, and other files, you can use the functions
mentioned in <a class="xref" href="#creation">[creation]</a>.</p><p>To address a file in the current module directory, use the variable "$moddir".</p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_module_setup_sh_installkernel"></a>module-setup.sh: installkernel()</h3></div></div></div><p>In installkernel() all kernel related files should be installed. You can use all
of the functions mentioned in <a class="xref" href="#creation">[creation]</a> to install files.</p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_anchor_id_creation_xreflabel_creation_creation_functions"></a><a id="creation"></a>Creation Functions</h3></div></div></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="_inst_multiple_o_lt_file_gt_lt_file_gt_8230"></a>inst_multiple [-o] <file> [ <file> …]</h4></div></div></div><p>installs multiple binaries and files. If executables are specified without a
path, dracut will search the path PATH=/usr/sbin:/sbin:/usr/bin:/bin for the
binary. If the option "-o" is given as the first parameter, a missing file does
not lead to an error.</p></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="_inst_lt_src_gt_lt_dst_gt"></a>inst <src> [<dst>]</h4></div></div></div><p>installs <span class="emphasis"><em>one</em></span> file <src> either to the same place in the initramfs or to an
optional <dst>. inst with more than two arguments is treated the same as
inst_multiple, all arguments are treated as files to install and none as
install destinations.</p></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="_inst_hook_lt_hookdir_gt_lt_prio_gt_lt_src_gt"></a>inst_hook <hookdir> <prio> <src></h4></div></div></div><p>installs an executable/script <src> in the dracut hook <hookdir> with priority
<prio>.</p></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="_inst_rules_lt_udevrule_gt_lt_udevrule_gt_8230"></a>inst_rules <udevrule> [ <udevrule> …]</h4></div></div></div><p>installs one or more udev rules. Non-existant udev rules are reported, but do
not let dracut fail.</p></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="_instmods_lt_kernelmodule_gt_lt_kernelmodule_gt_8230"></a>instmods <kernelmodule> [ <kernelmodule> … ]</h4></div></div></div><p>instmods should be used only in the installkernel() function.</p><p>instmods installs one or more kernel modules in the initramfs. <kernelmodule>
can also be a whole subsystem, if prefixed with a "=", like "=drivers/net/team".</p><p>instmods will not install the kernel module, if $hostonly is set and the kernel
module is not currently needed by any /sys/<span class="strong"><strong>…</strong></span>/uevent MODALIAS.
To install a kernel module regardless of the hostonly mode use the form:</p><pre class="screen">hostonly='' instmods <kernelmodule></pre></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_initramfs_functions"></a>Initramfs Functions</h3></div></div></div><p>FIXME</p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="_network_modules"></a>Network Modules</h3></div></div></div><p>FIXME</p></div></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="_author_3"></a>AUTHOR</h2></div></div></div><p>Harald Hoyer</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="_see_also_5"></a>SEE ALSO</h2></div></div></div><p><span class="strong"><strong>dracut</strong></span>(8)</p></div></div><div class="chapter"><div class="titlepage"><div><div><h2 class="title"><a id="dracutbootup7"></a>Chapter 12. DRACUT.BOOTUP(7)</h2></div></div></div><div class="toc"><p><strong>Table of Contents</strong></p><dl class="toc"><dt><span class="section"><a href="#_name_6">NAME</a></span></dt><dt><span class="section"><a href="#_description_6">DESCRIPTION</a></span></dt><dt><span class="section"><a href="#_author_4">AUTHOR</a></span></dt><dt><span class="section"><a href="#_see_also_6">SEE ALSO</a></span></dt></dl></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="_name_6"></a>NAME</h2></div></div></div><p>dracut.bootup - boot ordering in the initramfs</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="_description_6"></a>DESCRIPTION</h2></div></div></div><p>This flow chart illustrates the ordering of the services, if systemd is used in
the dracut initramfs.</p><pre class="screen"> systemd-journal.socket
|
v
dracut-cmdline.service
|
v
dracut-pre-udev.service
|
v
systemd-udevd.service
|
v
local-fs-pre.target dracut-pre-trigger.service
| |
v v
(various mounts) (various swap systemd-udev-trigger.service
| devices...) | (various low-level (various low-level
| | | services: seed, API VFS mounts:
v v v tmpfiles, random mqueue, configfs,
local-fs.target swap.target dracut-initqueue.service sysctl, ...) debugfs, ...)
| | | | |
\_______________|____________________ | ___________________|____________________/
\|/
v
sysinit.target
|
_________________/|\___________________
/ | \
| | |
v | v
(various | rescue.service
sockets...) | |
| | v
v | rescue.target
sockets.target |
| |
\_________________ | emergency.service
\| |
v v
basic.target emergency.target
|
______________________/|
/ |
| v
| dracut-pre-mount.service
| |
| v
| sysroot.mount
| |
| v
| initrd-root-fs.target
(custom initrd services) |
| v
| dracut-mount.service
| |
| v
| initrd-parse-etc.service
| |
| v
| (sysroot-usr.mount and
| various mounts marked
| with fstab option
| x-initrd.mount)
| |
| v
| initrd-fs.target
\______________________ |
\|
v
initrd.target
|
v
dracut-pre-pivot.service
|
v
initrd-cleanup.service
isolates to
initrd-switch-root.target
|
v
______________________/|
/ |
| initrd-udevadm-cleanup-db.service
| |
(custom initrd services) |
| |
\______________________ |
\|
v
initrd-switch-root.target
|
v
initrd-switch-root.service
|
v
switch-root</pre></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="_author_4"></a>AUTHOR</h2></div></div></div><p>Harald Hoyer</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="_see_also_6"></a>SEE ALSO</h2></div></div></div><p><span class="strong"><strong>dracut</strong></span>(8) <span class="strong"><strong>bootup</strong></span>(7)</p></div></div><div class="appendix"><div class="titlepage"><div><div><h2 class="title"><a id="_license"></a>Appendix A. License</h2></div></div></div><p>This work is licensed under the Creative Commons Attribution/Share-Alike
License. To view a copy of this license, visit
<a class="ulink" href="http://creativecommons.org/licenses/by-sa/3.0/" target="_top">http://creativecommons.org/licenses/by-sa/3.0/</a> or send a letter to Creative
Commons, 559 Nathan Abbott Way, Stanford, California 94305, USA.</p></div></div></div></body></html>
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