9 dracut - low-level tool for generating an initramfs/initrd image
13 *dracut* [__OPTION...__] [__<image>__ [__<kernel version>__]]
18 Create an initramfs <image> for the kernel with the version <kernel version>.
19 If <kernel version> is omitted, then the version of the actual running
20 kernel is used. If <image> is omitted or empty, then the default location
21 /boot/initramfs-<kernel version>.img is used.
23 dracut creates an initial image used by the kernel for preloading the block
24 device modules (such as IDE, SCSI or RAID) which are needed to access the root
25 filesystem, mounting the root filesystem and booting into the real system.
27 At boot time, the kernel unpacks that archive into RAM disk, mounts and uses it
28 as initial root file system. All finding of the root device happens in this
31 Initramfs images are also called "initrd".
33 For a complete list of kernel command line options see *dracut.cmdline*(7).
35 If you are dropped to an emergency shell, while booting your initramfs,
36 the file _/run/initramfs/rdsosreport.txt_ is created, which can be saved to a
37 (to be mounted by hand) partition (usually /boot) or a USB stick.
38 Additional debugging info can be produced by adding **rd.debug** to the kernel
39 command line. _/run/initramfs/rdsosreport.txt_ contains all logs and the output
40 of some tools. It should be attached to any report about dracut problems.
45 include::dracut.usage.asc[]
49 **--kver** _<kernel version>_::
50 set the kernel version. This enables to specify the kernel version, without
51 specifying the location of the initramfs image. For example:
53 # dracut --kver 3.5.0-0.rc7.git1.2.fc18.x86_64
57 overwrite existing initramfs file.
59 **-a, --add** _<list of dracut modules>_::
60 add a space-separated list of dracut modules to the default set of modules.
61 This parameter can be specified multiple times.
64 ===============================
65 If [LIST] has multiple arguments, then you have to put these in quotes. For
68 # dracut --add "module1 module2" ...
70 ===============================
72 **--force-add** _<list of dracut modules>_::
73 force to add a space-separated list of dracut modules to the default set of
74 modules, when -H is specified. This parameter can be specified multiple
78 ===============================
79 If [LIST] has multiple arguments, then you have to put these in quotes. For
82 # dracut --force-add "module1 module2" ...
84 ===============================
86 **-o, --omit** _<list of dracut modules>_::
87 omit a space-separated list of dracut modules. This parameter can be
88 specified multiple times.
91 ===============================
92 If [LIST] has multiple arguments, then you have to put these in quotes. For
95 # dracut --omit "module1 module2" ...
97 ===============================
99 **-m, --modules** _<list of dracut modules>_::
100 specify a space-separated list of dracut modules to call when building the
101 initramfs. Modules are located in _/usr/lib/dracut/modules.d_. This
102 parameter can be specified multiple times.
103 This option forces dracut to only include the specified dracut modules.
104 In most cases the "--add" option is what you want to use.
107 ===============================
108 If [LIST] has multiple arguments, then you have to put these in quotes. For
111 # dracut --modules "module1 module2" ...
113 ===============================
115 **-d, --drivers** _<list of kernel modules>_::
116 specify a space-separated list of kernel modules to exclusively include
117 in the initramfs. The kernel modules have to be specified without the ".ko"
118 suffix. This parameter can be specified multiple times.
121 ===============================
122 If [LIST] has multiple arguments, then you have to put these in quotes. For
125 # dracut --drivers "kmodule1 kmodule2" ...
127 ===============================
129 **--add-drivers** _<list of kernel modules>_::
130 specify a space-separated list of kernel modules to add to the initramfs.
131 The kernel modules have to be specified without the ".ko" suffix. This
132 parameter can be specified multiple times.
135 ===============================
136 If [LIST] has multiple arguments, then you have to put these in quotes. For
139 # dracut --add-drivers "kmodule1 kmodule2" ...
141 ===============================
143 **--force-drivers** _<list of kernel modules>_::
144 See add-drivers above. But in this case it is ensured that the drivers
145 are tried to be loaded early via modprobe.
148 ===============================
149 If [LIST] has multiple arguments, then you have to put these in quotes. For
152 # dracut --force-drivers "kmodule1 kmodule2" ...
154 ===============================
156 **--omit-drivers** _<list of kernel modules>_::
157 specify a space-separated list of kernel modules not to add to the
159 The kernel modules have to be specified without the ".ko" suffix. This
160 parameter can be specified multiple times.
163 ===============================
164 If [LIST] has multiple arguments, then you have to put these in quotes. For
167 # dracut --omit-drivers "kmodule1 kmodule2" ...
169 ===============================
171 **--filesystems** _<list of filesystems>_::
172 specify a space-separated list of kernel filesystem modules to exclusively
173 include in the generic initramfs. This parameter can be specified multiple
177 ===============================
178 If [LIST] has multiple arguments, then you have to put these in quotes. For
181 # dracut --filesystems "filesystem1 filesystem2" ...
183 ===============================
185 **-k, --kmoddir** _<kernel directory>_::
186 specify the directory, where to look for kernel modules
188 **--fwdir** _<dir>[:<dir>...]++_::
189 specify additional directories, where to look for firmwares. This parameter
190 can be specified multiple times.
192 **--kernel-cmdline <parameters>**::
193 specify default kernel command line parameters
197 only install kernel drivers and firmware files
200 do not install kernel drivers and firmware files
202 **--early-microcode**::
203 Combine early microcode with ramdisk
205 **--no-early-microcode**::
206 Do not combine early microcode with ramdisk
208 **--print-cmdline**::
209 print the kernel command line for the current disk layout
212 include local _/etc/mdadm.conf_
215 do not include local _/etc/mdadm.conf_
218 include local _/etc/lvm/lvm.conf_
221 do not include local _/etc/lvm/lvm.conf_
224 add a space-separated list of fsck tools, in addition to _dracut.conf_'s
225 specification; the installation is opportunistic (non-existing tools are
229 ===============================
230 If [LIST] has multiple arguments, then you have to put these in quotes. For
233 # dracut --fscks "fsck.foo barfsck" ...
235 ===============================
238 inhibit installation of any fsck tools
241 strip binaries in the initramfs (default)
244 do not strip binaries in the initramfs
247 hardlink files in the initramfs (default)
250 do not hardlink files in the initramfs
252 **--prefix** _<dir>_::
253 prefix initramfs files with the specified directory
256 do not prefix initramfs files (default)
259 display help text and exit.
262 output debug information of the build process
265 increase verbosity level (default is info(4))
267 **-q, --quiet**:: decrease verbosity level (default is info(4))
269 **-c, --conf** _<dracut configuration file>_::
270 specify configuration file to use.
275 **--confdir** _<configuration directory>_::
276 specify configuration directory to use.
281 **--tmpdir** _<temporary directory>_::
282 specify temporary directory to use.
287 **--sshkey** _<sshkey file>_:: ssh key file used with ssh-client module.
289 **--logfile** _<logfile>_:: logfile to use; overrides any setting from
290 the configuration files.
293 _/var/log/dracut.log_
296 activates the local mode. dracut will use modules from the current working
297 directory instead of the system-wide installed modules in
298 _/usr/lib/dracut/modules.d_.
299 This is useful when running dracut from a git checkout.
302 Host-Only mode: Install only what is needed for booting the local host
303 instead of a generic host and generate host-specific configuration.
307 If chrooted to another root other than the real root device, use "--fstab" and
308 provide a valid _/etc/fstab_.
311 **-N, --no-hostonly**::
312 Disable Host-Only mode
314 **--hostonly-cmdline**:
315 Store kernel command line arguments needed in the initramfs
317 **--no-hostonly-cmdline**:
318 Do not store kernel command line arguments needed in the initramfs
320 **--no-hostonly-default-device**:
321 Do not generate implicit host devices like root, swap, fstab, etc.
322 Use "--mount" or "--add-device" to explicitly add devices as needed.
325 Install only needed keyboard and font files according to the host configuration (default).
327 **--no-hostonly-i18n**:
328 Install all keyboard and font files available.
330 **--persistent-policy** _<policy>_::
331 Use _<policy>_ to address disks and partitions.
332 _<policy>_ can be any directory name found in /dev/disk.
333 E.g. "by-uuid", "by-label"
336 Use _/etc/fstab_ instead of _/proc/self/mountinfo_.
338 **--add-fstab** _<filename>_::
339 Add entries of _<filename>_ to the initramfs /etc/fstab.
341 **--mount** "_<device>_ _<mountpoint>_ _<filesystem type>_ [_<filesystem options>_ [_<dump frequency>_ [_<fsck order>_]]]"::
342 Mount _<device>_ on _<mountpoint>_ with _<filesystem type>_ in the
343 initramfs. _<filesystem options>_, _<dump options>_ and _<fsck order>_ can
344 be specified, see fstab manpage for the details.
345 The default _<filesystem options>_ is "defaults".
346 The default _<dump frequency>_ is "0".
347 the default _<fsck order>_ is "2".
349 **--mount** "_<mountpoint>_"::
350 Like above, but _<device>_, _<filesystem type>_ and _<filesystem options>_
351 are determined by looking at the current mounts.
353 **--add-device** _<device>_ ::
354 Bring up _<device>_ in initramfs, _<device>_ should be the device name.
355 This can be useful in hostonly mode for resume support when your swap is on
356 LVM or an encrypted partition.
357 [NB --device can be used for compatibility with earlier releases]
359 **-i, --include** _<SOURCE>_ _<TARGET>_::
360 include the files in the SOURCE directory into the
361 TARGET directory in the final initramfs. If SOURCE is a file, it will be
362 installed to TARGET in the final initramfs. This parameter can be specified
365 **-I, --install** _<file list>_::
366 install the space separated list of files into the initramfs.
369 ===============================
370 If [LIST] has multiple arguments, then you have to put these in quotes. For
373 # dracut --install "/bin/foo /sbin/bar" ...
375 ===============================
377 **--install-optional** _<file list>_::
378 install the space separated list of files into the initramfs, if they exist.
381 Compress the generated initramfs using gzip. This will be done by default,
382 unless another compression option or --no-compress is passed. Equivalent to
386 Compress the generated initramfs using bzip2.
390 Make sure your kernel has bzip2 decompression support compiled in, otherwise you
391 will not be able to boot. Equivalent to "--compress=bzip2"
395 Compress the generated initramfs using lzma.
399 Make sure your kernel has lzma decompression support compiled in, otherwise you
400 will not be able to boot. Equivalent to "lzma --compress=lzma -9"
404 Compress the generated initramfs using xz.
408 Make sure your kernel has xz decompression support compiled in, otherwise you
409 will not be able to boot. Equivalent to
410 "lzma --compress=xz --check=crc32 --lzma2=dict=1MiB"
414 Compress the generated initramfs using lzop.
417 Make sure your kernel has lzo decompression support compiled in, otherwise you
418 will not be able to boot.
422 Compress the generated initramfs using lz4.
425 Make sure your kernel has lz4 decompression support compiled in, otherwise you
426 will not be able to boot.
430 Compress the generated initramfs using Zstandard.
433 Make sure your kernel has zstd decompression support compiled in, otherwise you
434 will not be able to boot.
437 **--compress** _<compressor>_::
438 Compress the generated initramfs using the passed compression program. If
439 you pass it just the name of a compression program, it will call that
440 program with known-working arguments. If you pass a quoted string with
441 arguments, it will be called with exactly those arguments. Depending on what
442 you pass, this may result in an initramfs that the kernel cannot decompress.
443 The default value can also be set via the _INITRD_COMPRESS_ environment variable.
446 Do not compress the generated initramfs. This will override any other
450 Create reproducible images.
452 **--no-reproducible**::
453 Do not create reproducible images.
456 List all available dracut modules.
458 **-M, --show-modules**::
459 Print included module's name to standard output during build.
462 Keep the initramfs temporary directory for debugging purposes.
465 Print out the module install size
468 Output profile information of the build process
471 Mount / and /usr read-only by default.
473 **-L, --stdlog** _<level>_::
474 [0-6] Specify logging level (to standard error)
476 0 - suppress any messages
477 1 - only fatal errors
481 5 - debug info (here starts lots of output)
482 6 - trace info (and even more)
485 **--regenerate-all**::
486 Regenerate all initramfs images at the default location with the kernel
487 versions found on the system. Additional parameters are passed through.
489 **--loginstall _<DIR>_**::
490 Log all files installed from the host to _<DIR>_.
493 Instead of creating an initramfs image, dracut will create an UEFI executable,
494 which can be executed by an UEFI BIOS. The default output filename is
495 _<EFI>/EFI/Linux/linux-$kernel$-<MACHINE_ID>-<BUILD_ID>.efi_. <EFI> might be
496 _/efi_, _/boot_ or _/boot/efi_ depending on where the ESP partition is mounted.
497 The <BUILD_ID> is taken from BUILD_ID in _/usr/lib/os-release_ or if it exists
498 _/etc/os-release_ and is left out, if BUILD_ID is non-existant or empty.
501 affects the default output filename of **--uefi** and will discard the <MACHINE_ID>
504 **--uefi-stub _<FILE>_**::
505 Specifies the UEFI stub loader, which will load the attached kernel, initramfs and
506 kernel command line and boots the kernel. The default is
507 _$prefix/lib/systemd/boot/efi/linux<EFI-MACHINE-TYPE-NAME>.efi.stub_
508 or _$prefix/lib/gummiboot/linux<EFI-MACHINE-TYPE-NAME>.efi.stub_
510 **--kernel-image _<FILE>_**::
511 Specifies the kernel image, which to include in the UEFI executable. The default is
512 _/lib/modules/<KERNEL-VERSION>/vmlinuz_ or _/boot/vmlinuz-<KERNEL-VERSION>_
518 sets the default compression program. See **--compress**.
522 _/var/log/dracut.log_::
523 logfile of initramfs image creation
526 logfile of initramfs image creation, if _/var/log/dracut.log_ is not
532 _/etc/dracut.conf.d/*.conf_::
535 _/usr/lib/dracut/dracut.conf.d/*.conf_::
538 Configuration in the initramfs
539 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
541 Any files found in _/etc/conf.d/_ will be sourced in the initramfs to
542 set initial values. Command line options will override these values
543 set in the configuration files.
546 Can contain additional command line options. Deprecated, better use
547 /etc/cmdline.d/*.conf.
549 _/etc/cmdline.d/*.conf_::
550 Can contain additional command line options.
554 The dracut command is part of the dracut package and is available from
555 link:$$https://dracut.wiki.kernel.org$$[https://dracut.wiki.kernel.org]
577 *dracut.cmdline*(7) *dracut.conf*(5) *lsinitrd*(1)