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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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NAME | SYNOPSIS | DESCRIPTION | CONFIGURATION OPTIONS | FILES | AUTHOR | SEE ALSO |
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DRACUT.CONF(5) dracut DRACUT.CONF(5)
dracut.conf - configuration file(s) for dracut
/etc/dracut.conf /etc/dracut.conf.d/*.conf
/usr/lib/dracut/dracut.conf.d/*.conf
dracut.conf is loaded during the initialization phase of dracut.
*.conf 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 /etc/dracut.conf. Each line specifies an
attribute and a value. A '#' indicates the beginning of a comment;
the following characters, up to the end of the line, are not
interpreted.
dracut command line options will override any values set here.
Configuration files must have the extension .conf; other
extensions are ignored.
add_dracutmodules+=" <dracut modules> "
Add a space-separated list of dracut modules to call when
building the initramfs. Modules are located in
/usr/lib/dracut/modules.d.
force_add_dracutmodules+=" <dracut modules> "
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.
omit_dracutmodules+=" <dracut modules> "
Omit a space-separated list of dracut modules to call when
building the initramfs. Modules are located in
/usr/lib/dracut/modules.d.
Warning
Avoid manually omitting dracut modules, as you may
inadvertently remove essential ones that dracut can’t
detect or warn you about. Using this option is not
recommended and is at your own risk.
dracutmodules+=" <dracut modules> "
Specify a space-separated list of dracut modules to call when
building the initramfs. Modules are located in
/usr/lib/dracut/modules.d. This option forces dracut to only
include the specified dracut modules. In most cases the
"add_dracutmodules" option is what you want to use. This
option is not recommended to use (use at your own risk).
add_drivers+=" <kernel modules> "
Specify a space-separated list of kernel modules to add to the
initramfs. The kernel modules have to be specified without the
".ko" suffix.
force_drivers+=" <list of kernel modules> "
See add_drivers above. But in this case it is ensured that the
drivers are tried to be loaded early via modprobe.
omit_drivers+=" <kernel modules> "
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.
drivers+=" <kernel modules> "
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 option forces
dracut to only include the specified kernel modules. In most
cases the "--add-drivers" option is what you want to use. This
option is not recommended to use (use at your own risk).
add_dlopen_features+=" <pattern>:<feature>[,<feature>...] ... "
Specify a space-separated list of binaries matching pattern
against a comma-separated list of features to install
dependencies for. For example,
"libsystemd-shared-*.so:idn,ip4tc" will install the
dependencies for systemd’s international domain name and
iptables support. pattern should match the soname for
libraries or the filename for executables.
omit_dlopen_features+=" <pattern>:<feature>[,<feature>...] ... "
Specify a space-separated list of binaries matching pattern
against a comma-separated list of features to omit
dependencies for. Some dracut modules add certain features by
default. This takes precedence over add_dlopen_features above.
filesystems+=" <filesystem names> "
Specify a space-separated list of kernel filesystem modules to
exclusively include in the generic initramfs.
drivers_dir="<kernel modules directory>"
Specify the directory where to look for kernel modules.
fw_dir+=" :<dir>[:<dir> ...] "
Specify additional colon-separated list of directories where
to look for firmware files.
libdirs+=" <dir>[ <dir> ...] "
Specify a space-separated list of directories where to look
for libraries.
install_items+=" <file>[ <file> ...] "
Specify additional files to include in the initramfs,
separated by spaces.
remove_items+=" <file/dir>[ <file/dir> ...] "
Specify additional files or directories to remove from the
generated initramfs, separated by spaces. Warning: Avoid
manually removing files or directories, as you may
inadvertently remove essential ones that dracut won’t detect
or warn you about. Using this option is not recommended and is
at your own risk.
install_optional_items+=" <file>[ <file> ...] "
Specify additional files to include in the initramfs,
separated by spaces, if they exist.
compress="{cat|bzip2|lzma|xz|gzip|lzop|lz4|zstd|<compressor [args
...]>}"
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".
squash_compress="{<compressor [args ...]>}"
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.
do_strip="{yes|no}"
Strip binaries in the initramfs (default=yes).
aggressive_strip="{yes|no}"
Strip more than just debug symbol and sections, for a smaller
initramfs build. The "do_strip=yes" option must also be
specified (default=no).
do_hardlink="{yes|no}"
Hardlink files in the initramfs (default=yes).
prefix=" <directory> "
Prefix initramfs files with <directory>.
hostonly="{yes|no}"
Host-only mode: Install only what is needed for booting the
local host instead of a generic host and generate
host-specific configuration (default=yes).
hostonly_mode="{sloppy|strict}"
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 make additional efforts to save more space. Minor
changes in hardware or environment can make the image
unbootable.
hostonly_cmdline="{yes|no}"
If set to "yes", store the kernel command line arguments
needed in the initramfs. If hostonly="yes" and this option is
not configured, it’s automatically set to "yes". (default=no)
hostonly_nics+=" [<nic>[ <nic> ...]] "
Only enable listed NICs in the initramfs. The list can be
empty, so other modules can install only the necessary network
drivers.
persistent_policy="<policy>"
Use <policy> to address disks and partitions. <policy> can be
any directory name found in /dev/disk (e.g. "by-uuid",
"by-label"), or "mapper" to use /dev/mapper device names
(default=mapper).
tmpdir="<temporary directory>"
Specify temporary directory to use.
Warning
If chrooted to another root other than the real root
device, use --fstab and provide a valid /etc/fstab.
use_fstab="{yes|no}"
Use /etc/fstab instead of /proc/self/mountinfo (default=no).
add_fstab+=" <filename> "
Add entries of <filename> to the initramfs /etc/fstab.
add_device+=" <device> "
Bring up <device> in initramfs, <device> 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.
mdadmconf="{yes|no}"
Include local /etc/mdadm.conf (default=no).
lvmconf="{yes|no}"
Include local /etc/lvm/lvm.conf (default=no).
fscks=" <fsck tools> "
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
btrfsck.
The installation is opportunistic (non-existing tools are
ignored).
nofscks="{yes|no}"
If specified, inhibit installation of any fsck tools
(default=no).
ro_mnt="{yes|no}"
Mount / and /usr read-only by default (default=no).
kernel_cmdline="parameters"
Specify default kernel command line parameters. Despite its
name, this command only sets initrd parameters.
kernel_only="{yes|no}"
Only install kernel drivers and firmware files (default=no).
no_kernel="{yes|no}"
Do not install kernel drivers and firmware files (default=no).
acpi_override="{yes|no}"
Caution
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
<https://www.kernel.org/doc/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).
acpi_table_dir="<dir>"
Directory to search for ACPI tables if acpi_override= is set
to yes.
early_microcode="{yes|no}"
Combine early microcode with ramdisk (default=yes).
stdloglvl="{0-6}"
Specify logging level for standard error (default=4).
Table 1. Logging Levels
┌───┬─────────────────────────┐
│ │ │
│ 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) │
└───┴─────────────────────────┘
sysloglvl="{0-6}"
Specify logging level for syslog (default=0).
fileloglvl="{0-6}"
Specify logging level for logfile (default=4).
logfile="<file>"
Path to logfile.
sshkey="<file>"
SSH key file used with ssh-client module.
show_modules="{yes|no}"
Print the name of the included modules to standard output
during build (default=no).
i18n_vars="<variable mapping>"
Distribution specific variable mapping. See
dracut/modules.d/10i18n/README for a detailed description.
i18n_default_font="<fontname>"
The font <fontname> to install, if not specified otherwise.
Default is "eurlatgr".
i18n_install_all="{yes|no}"
Install everything regardless of generic or host-only mode
(default=no).
reproducible="{yes|no}"
Create reproducible images (default=no).
noimageifnotneeded="{yes|no}"
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).
loginstall="<directory>"
Log all files installed from the host to <directory>.
uefi="{yes|no}"
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
<EFI>/EFI/Linux/linux-$kernel$-<MACHINE_ID>-<BUILD_ID>.efi.
<EFI> might be /efi, /boot or /boot/efi depending on where the
ESP partition is mounted. The <BUILD_ID> is taken from
BUILD_ID in /usr/lib/os-release or if it exists
/etc/os-release and is left out, if BUILD_ID is non-existent
or empty.
machine_id="{yes|no}"
Affects the default output filename of the UEFI executable,
including the <MACHINE_ID> part (default=yes).
uefi_stub="<file>"
Specifies the UEFI stub loader, which will load the attached
kernel, initramfs and kernel command line and boots the
kernel. The default is
/lib/systemd/boot/efi/linux<EFI-MACHINE-TYPE-NAME>.efi.stub.
uefi_splash_image="<file>"
Specifies the UEFI stub loader’s splash image. Requires bitmap
(.bmp) image format.
uefi_secureboot_cert="<file>", uefi_secureboot_key="<file>"
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 sbsign to be installed.
uefi_secureboot_engine="parameter"
Specifies an engine to use when signing the created UEFI
executable. E.g. "pkcs11"
kernel_image="<file>"
Specifies the kernel image, which to include in the UEFI
executable. The default is
/lib/modules/<KERNEL-VERSION>/vmlinuz or
/boot/vmlinuz-<KERNEL-VERSION>.
sbat="parameters"
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,https://github.com/rhboot/shim/blob/main/SBAT.md.
enhanced_cpio="{yes|no}"
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
compress="cat" and do_strip="no" parameters, with initramfs
source files, tmpdir staging area and destination all on the
same copy-on-write capable file-system.
parallel="{yes|no}"
If set to yes, try to execute tasks in parallel (currently
only supported for --regenerate-all).
initrdname="<filepattern>"
Specifies the file name for the generated initramfs if it is
not set otherwise.
The initrdname configuration option is required to match the
initr*${kernel}* file pattern and only one file with this
pattern should exists in the directory where initramfs is
loaded from.
Defaults to initramfs-${kernel}.img.
/etc/dracut.conf
Old configuration file. It is recommended to use individual
files in /etc/dracut.conf.d/.
/etc/dracut.conf.d/
Any /etc/dracut.conf.d/*.conf file can override the values in
/etc/dracut.conf. The configuration files are read in
alphanumerical order. The recommended ordering for
distribution or user provided configuration is in the range of
50-59.
Harald Hoyer
man:dracut[8] man:dracut.cmdline[7].SH COLOPHON This page is part
of the dracut (event driven initramfs infrastructure) project.
Information about the project can be found at
⟨https://github.com/dracut-ng//dracut-ng⟩. If you have a bug report
for this manual page, see
⟨https://github.com/dracut-ng/dracut-ng/issues⟩. This page was
obtained from the project's upstream Git repository
⟨https://github.com/dracut-ng/dracut-ng.git⟩ on 2025-08-11. (At
that time, the date of the most recent commit that was found in
the repository was 2025-08-09.) If you discover any rendering
problems in this HTML version of the page, or you believe there is
a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
[email protected]
dracut 2025-08-09 DRACUT.CONF(5)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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