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 prelink binaries in the initramfs (default)
250 do not prelink binaries in the initramfs
253 hardlink files in the initramfs (default)
256 do not hardlink files in the initramfs
258 **--prefix** _<dir>_::
259 prefix initramfs files with the specified directory
262 do not prefix initramfs files (default)
265 display help text and exit.
268 output debug information of the build process
271 increase verbosity level (default is info(4))
273 **-q, --quiet**:: decrease verbosity level (default is info(4))
275 **-c, --conf** _<dracut configuration file>_::
276 specify configuration file to use.
281 **--confdir** _<configuration directory>_::
282 specify configuration directory to use.
287 **--tmpdir** _<temporary directory>_::
288 specify temporary directory to use.
293 **--sshkey** _<sshkey file>_:: ssh key file used with ssh-client module.
295 **--logfile** _<logfile>_:: logfile to use; overrides any setting from
296 the configuration files.
299 _/var/log/dracut.log_
302 activates the local mode. dracut will use modules from the current working
303 directory instead of the system-wide installed modules in
304 _/usr/lib/dracut/modules.d_.
305 This is useful when running dracut from a git checkout.
308 Host-Only mode: Install only what is needed for booting the local host
309 instead of a generic host and generate host-specific configuration.
313 If chrooted to another root other than the real root device, use "--fstab" and
314 provide a valid _/etc/fstab_.
317 **-N, --no-hostonly**::
318 Disable Host-Only mode
320 **--hostonly-cmdline**:
321 Store kernel command line arguments needed in the initramfs
323 **--no-hostonly-cmdline**:
324 Do not store kernel command line arguments needed in the initramfs
327 Install only needed keyboard and font files according to the host configuration (default).
329 **--no-hostonly-i18n**:
330 Install all keyboard and font files available.
332 **--persistent-policy** _<policy>_::
333 Use _<policy>_ to address disks and partitions.
334 _<policy>_ can be any directory name found in /dev/disk.
335 E.g. "by-uuid", "by-label"
338 Use _/etc/fstab_ instead of _/proc/self/mountinfo_.
340 **--add-fstab** _<filename>_::
341 Add entries of _<filename>_ to the initramfs /etc/fstab.
343 **--mount** "_<device>_ _<mountpoint>_ _<filesystem type>_ [_<filesystem options>_ [_<dump frequency>_ [_<fsck order>_]]]"::
344 Mount _<device>_ on _<mountpoint>_ with _<filesystem type>_ in the
345 initramfs. _<filesystem options>_, _<dump options>_ and _<fsck order>_ can
346 be specified, see fstab manpage for the details.
347 The default _<filesystem options>_ is "defaults".
348 The default _<dump frequency>_ is "0".
349 the default _<fsck order>_ is "2".
351 **--mount** "_<mountpoint>_"::
352 Like above, but _<device>_, _<filesystem type>_ and _<filesystem options>_
353 are determined by looking at the current mounts.
355 **--add-device** _<device>_ ::
356 Bring up _<device>_ in initramfs, _<device>_ should be the device name.
357 This can be useful in hostonly mode for resume support when your swap is on
358 LVM or an encrypted partition.
359 [NB --device can be used for compatibility with earlier releases]
361 **-i, --include** _<SOURCE>_ _<TARGET>_::
362 include the files in the SOURCE directory into the
363 TARGET directory in the final initramfs. If SOURCE is a file, it will be
364 installed to TARGET in the final initramfs. This parameter can be specified
367 **-I, --install** _<file list>_::
368 install the space separated list of files into the initramfs.
371 ===============================
372 If [LIST] has multiple arguments, then you have to put these in quotes. For
375 # dracut --install "/bin/foo /sbin/bar" ...
377 ===============================
379 **--install-optional** _<file list>_::
380 install the space separated list of files into the initramfs, if they exist.
383 Compress the generated initramfs using gzip. This will be done by default,
384 unless another compression option or --no-compress is passed. Equivalent to
388 Compress the generated initramfs using bzip2.
392 Make sure your kernel has bzip2 decompression support compiled in, otherwise you
393 will not be able to boot. Equivalent to "--compress=bzip2"
397 Compress the generated initramfs using lzma.
401 Make sure your kernel has lzma decompression support compiled in, otherwise you
402 will not be able to boot. Equivalent to "lzma --compress=lzma -9"
406 Compress the generated initramfs using xz.
410 Make sure your kernel has xz decompression support compiled in, otherwise you
411 will not be able to boot. Equivalent to
412 "lzma --compress=xz --check=crc32 --lzma2=dict=1MiB"
416 Compress the generated initramfs using lzop.
419 Make sure your kernel has lzo decompression support compiled in, otherwise you
420 will not be able to boot.
424 Compress the generated initramfs using lz4.
427 Make sure your kernel has lz4 decompression support compiled in, otherwise you
428 will not be able to boot.
431 **--compress** _<compressor>_::
432 Compress the generated initramfs using the passed compression program. If
433 you pass it just the name of a compression program, it will call that
434 program with known-working arguments. If you pass a quoted string with
435 arguments, it will be called with exactly those arguments. Depending on what
436 you pass, this may result in an initramfs that the kernel cannot decompress.
437 The default value can also be set via the _INITRD_COMPRESS_ environment variable.
440 Do not compress the generated initramfs. This will override any other
444 Create reproducible images.
446 **--no-reproducible**::
447 Do not create reproducible images.
450 List all available dracut modules.
452 **-M, --show-modules**::
453 Print included module's name to standard output during build.
456 Keep the initramfs temporary directory for debugging purposes.
459 Print out the module install size
462 Output profile information of the build process
465 Mount / and /usr read-only by default.
467 **-L, --stdlog** _<level>_::
468 [0-6] Specify logging level (to standard error)
470 0 - suppress any messages
471 1 - only fatal errors
475 5 - debug info (here starts lots of output)
476 6 - trace info (and even more)
479 **--regenerate-all**::
480 Regenerate all initramfs images at the default location with the kernel
481 versions found on the system. Additional parameters are passed through.
483 **--loginstall _<DIR>_**::
484 Log all files installed from the host to _<DIR>_.
487 Instead of creating an initramfs image, dracut will create an UEFI executable,
488 which can be executed by an UEFI BIOS. The default output filename is
489 _<EFI>/EFI/Linux/linux-$kernel$-<MACHINE_ID>-<BUILD_ID>.efi_. <EFI> might be
490 _/efi_, _/boot_ or _/boot/efi_ depending on where the ESP partition is mounted.
491 The <BUILD_ID> is taken from BUILD_ID in _/usr/lib/os-release_ or if it exists
492 _/etc/os-release_ and is left out, if BUILD_ID is non-existant or empty.
495 affects the default output filename of **--uefi** and will discard the <MACHINE_ID>
498 **--uefi-stub _<FILE>_**::
499 Specifies the UEFI stub loader, which will load the attached kernel, initramfs and
500 kernel command line and boots the kernel. The default is
501 _$prefix/lib/systemd/boot/efi/linux<EFI-MACHINE-TYPE-NAME>.efi.stub_
502 or _$prefix/lib/gummiboot/linux<EFI-MACHINE-TYPE-NAME>.efi.stub_
504 **--kernel-image _<FILE>_**::
505 Specifies the kernel image, which to include in the UEFI executable. The default is
506 _/lib/modules/<KERNEL-VERSION>/vmlinuz_ or _/boot/vmlinuz-<KERNEL-VERSION>_
512 sets the default compression program. See **--compress**.
516 _/var/log/dracut.log_::
517 logfile of initramfs image creation
520 logfile of initramfs image creation, if _/var/log/dracut.log_ is not
526 _/etc/dracut.conf.d/*.conf_::
529 _/usr/lib/dracut/dracut.conf.d/*.conf_::
532 Configuration in the initramfs
533 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
535 Any files found in _/etc/conf.d/_ will be sourced in the initramfs to
536 set initial values. Command line options will override these values
537 set in the configuration files.
540 Can contain additional command line options. Deprecated, better use
541 /etc/cmdline.d/*.conf.
543 _/etc/cmdline.d/*.conf_::
544 Can contain additional command line options.
548 The dracut command is part of the dracut package and is available from
549 link:$$https://dracut.wiki.kernel.org$$[https://dracut.wiki.kernel.org]
571 *dracut.cmdline*(7) *dracut.conf*(5) *lsinitrd*(1)