1DRACUT(8)                           dracut                           DRACUT(8)
2
3
4

NAME

6       dracut - low-level tool for generating an initramfs/initrd image
7

SYNOPSIS

9       dracut [OPTION...] [<image> [<kernel version>]]
10

DESCRIPTION

12       Create an initramfs <image> for the kernel with the version <kernel
13       version>. If <kernel version> is omitted, then the version of the
14       actual running kernel is used. If <image> is omitted or empty,
15       depending on bootloader specification, the default location can be
16       /efi/<machine-id>/<kernel-version>/initrd,
17       /boot/<machine-id>/<kernel-version>/initrd,
18       /boot/efi/<machine-id>/<kernel-version>/initrd,
19       /lib/modules/<kernel-version>/initrd or
20       /boot/initramfs-<kernel-version>.img.
21
22       dracut creates an initial image used by the kernel for preloading the
23       block device modules (such as IDE, SCSI or RAID) which are needed to
24       access the root filesystem, mounting the root filesystem and booting
25       into the real system.
26
27       At boot time, the kernel unpacks that archive into RAM disk, mounts and
28       uses it as initial root file system. All finding of the root device
29       happens in this early userspace.
30
31       Initramfs images are also called "initrd".
32
33       For a complete list of kernel command line options see
34       dracut.cmdline(7).
35
36       If you are dropped to an emergency shell, while booting your initramfs,
37       the file /run/initramfs/rdsosreport.txt is created, which can be saved
38       to a (to be mounted by hand) partition (usually /boot) or a USB stick.
39       Additional debugging info can be produced by adding rd.debug to the
40       kernel command line. /run/initramfs/rdsosreport.txt contains all logs
41       and the output of some tools. It should be attached to any report about
42       dracut problems.
43

USAGE

45       To create a initramfs image, the most simple command is:
46
47           # dracut
48
49       This will generate a general purpose initramfs image, with all possible
50       functionality resulting of the combination of the installed dracut
51       modules and system tools. The image, depending on bootloader
52       specification, can be /efi/<machine-id>/<kernel-version>/initrd,
53       /boot/<machine-id>/<kernel-version>/initrd,
54       /boot/efi/<machine-id>/<kernel-version>/initrd,
55       /lib/modules/<kernel-version>/initrd or
56       /boot/initramfs-<kernel-version>.img and contains the kernel modules of
57       the currently active kernel with version <kernel-version>.
58
59       If the initramfs image already exists, dracut will display an error
60       message, and to overwrite the existing image, you have to use the
61       --force option.
62
63           # dracut --force
64
65       If you want to specify another filename for the resulting image you
66       would issue a command like:
67
68           # dracut foobar.img
69
70       To generate an image for a specific kernel version, the command would
71       be:
72
73           # dracut foobar.img 2.6.40-1.rc5.f20
74
75       A shortcut to generate the image at the default location for a specific
76       kernel version is:
77
78           # dracut --kver 2.6.40-1.rc5.f20
79
80       If you want to create lighter, smaller initramfs images, you may want
81       to specify the --hostonly or -H option. Using this option, the
82       resulting image will contain only those dracut modules, kernel modules
83       and filesystems, which are needed to boot this specific machine. This
84       has the drawback, that you can’t put the disk on another controller or
85       machine, and that you can’t switch to another root filesystem, without
86       recreating the initramfs image. The usage of the --hostonly option is
87       only for experts and you will have to keep the broken pieces. At least
88       keep a copy of a general purpose image (and corresponding kernel) as a
89       fallback to rescue your system.
90
91   Inspecting the Contents
92       To see the contents of the image created by dracut, you can use the
93       lsinitrd tool.
94
95           # lsinitrd | less
96
97       To display the contents of a file in the initramfs also use the
98       lsinitrd tool:
99
100           # lsinitrd -f /etc/ld.so.conf
101           include ld.so.conf.d/*.conf
102
103   Adding dracut Modules
104       Some dracut modules are turned off by default and have to be activated
105       manually. You can do this by adding the dracut modules to the
106       configuration file /etc/dracut.conf or /etc/dracut.conf.d/myconf.conf.
107       See dracut.conf(5). You can also add dracut modules on the command line
108       by using the -a or --add option:
109
110           # dracut --add module initramfs-module.img
111
112       To see a list of available dracut modules, use the --list-modules
113       option:
114
115           # dracut --list-modules
116
117   Omitting dracut Modules
118       Sometimes you don’t want a dracut module to be included for reasons of
119       speed, size or functionality. To do this, either specify the
120       omit_dracutmodules variable in the dracut.conf or
121       /etc/dracut.conf.d/myconf.conf configuration file (see dracut.conf(5)),
122       or use the -o or --omit option on the command line:
123
124           # dracut -o "multipath lvm" no-multipath-lvm.img
125
126   Adding Kernel Modules
127       If you need a special kernel module in the initramfs, which is not
128       automatically picked up by dracut, you have the use the --add-drivers
129       option on the command line or the drivers variable in the
130       /etc/dracut.conf or /etc/dracut.conf.d/myconf.conf configuration file
131       (see dracut.conf(5)):
132
133           # dracut --add-drivers mymod initramfs-with-mymod.img
134
135   Boot parameters
136       An initramfs generated without the "hostonly" mode, does not contain
137       any system configuration files (except for some special exceptions), so
138       the configuration has to be done on the kernel command line. With this
139       flexibility, you can easily boot from a changed root partition, without
140       the need to recompile the initramfs image. So, you could completely
141       change your root partition (move it inside a md raid with encryption
142       and LVM on top), as long as you specify the correct filesystem LABEL or
143       UUID on the kernel command line for your root device, dracut will find
144       it and boot from it.
145
146       The kernel command line can also be provided by the dhcp server with
147       the root-path option. See the section called “Network Boot”.
148
149       For a full reference of all kernel command line parameters, see
150       dracut.cmdline(7).
151
152       To get a quick start for the suitable kernel command line on your
153       system, use the --print-cmdline option:
154
155           # dracut --print-cmdline
156            root=UUID=8b8b6f91-95c7-4da2-831b-171e12179081 rootflags=rw,relatime,discard,data=ordered rootfstype=ext4
157
158       Specifying the root Device
159           This is the only option dracut really needs to boot from your root
160           partition. Because your root partition can live in various
161           environments, there are a lot of formats for the root= option. The
162           most basic one is root=<path to device node>:
163
164               root=/dev/sda2
165
166           Because device node names can change, dependent on the drive
167           ordering, you are encouraged to use the filesystem identifier
168           (UUID) or filesystem label (LABEL) to specify your root partition:
169
170               root=UUID=19e9dda3-5a38-484d-a9b0-fa6b067d0331
171
172           or
173
174               root=LABEL=myrootpartitionlabel
175
176           To see all UUIDs or LABELs on your system, do:
177
178               # ls -l /dev/disk/by-uuid
179
180           or
181
182               # ls -l /dev/disk/by-label
183
184           If your root partition is on the network see the section called
185           “Network Boot”.
186
187       Keyboard Settings
188           If you have to input passwords for encrypted disk volumes, you
189           might want to set the keyboard layout and specify a display font.
190
191           A typical german kernel command line would contain:
192
193               rd.vconsole.font=eurlatgr rd.vconsole.keymap=de-latin1-nodeadkeys rd.locale.LANG=de_DE.UTF-8
194
195           Setting these options can override the setting stored on your
196           system, if you use a modern init system, like systemd.
197
198       Blacklisting Kernel Modules
199           Sometimes it is required to prevent the automatic kernel module
200           loading of a specific kernel module. To do this, just add
201           rd.driver.blacklist=<kernel module name>, with <kernel module name>
202           not containing the .ko suffix, to the kernel command line. For
203           example:
204
205               rd.driver.blacklist=mptsas rd.driver.blacklist=nouveau
206
207           The option can be specified multiple times on the kernel command
208           line.
209
210       Speeding up the Boot Process
211           If you want to speed up the boot process, you can specify as much
212           information for dracut on the kernel command as possible. For
213           example, you can tell dracut, that you root partition is not on a
214           LVM volume or not on a raid partition, or that it lives inside a
215           specific crypto LUKS encrypted volume. By default, dracut searches
216           everywhere. A typical dracut kernel command line for a plain
217           primary or logical partition would contain:
218
219               rd.luks=0 rd.lvm=0 rd.md=0 rd.dm=0
220
221           This turns off every automatic assembly of LVM, MD raids, DM raids
222           and crypto LUKS.
223
224           Of course, you could also omit the dracut modules in the initramfs
225           creation process, but then you would lose the possibility to turn
226           it on on demand.
227
228   Injecting custom Files
229       To add your own files to the initramfs image, you have several
230       possibilities.
231
232       The --include option let you specify a source path and a target path.
233       For example
234
235           # dracut --include cmdline-preset /etc/cmdline.d/mycmdline.conf initramfs-cmdline-pre.img
236
237       will create an initramfs image, where the file cmdline-preset will be
238       copied inside the initramfs to /etc/cmdline.d/mycmdline.conf. --include
239       can only be specified once.
240
241           # mkdir -p rd.live.overlay/etc/cmdline.d
242           # mkdir -p rd.live.overlay/etc/conf.d
243           # echo "ip=dhcp" >> rd.live.overlay/etc/cmdline.d/mycmdline.conf
244           # echo export FOO=testtest >> rd.live.overlay/etc/conf.d/testvar.conf
245           # echo export BAR=testtest >> rd.live.overlay/etc/conf.d/testvar.conf
246           # tree rd.live.overlay/
247           rd.live.overlay/
248           `-- etc
249               |-- cmdline.d
250               |   `-- mycmdline.conf
251               `-- conf.d
252                   `-- testvar.conf
253
254           # dracut --include rd.live.overlay / initramfs-rd.live.overlay.img
255
256       This will put the contents of the rd.live.overlay directory into the
257       root of the initramfs image.
258
259       The --install option let you specify several files, which will get
260       installed in the initramfs image at the same location, as they are
261       present on initramfs creation time.
262
263           # dracut --install 'strace fsck.ext3 ssh' initramfs-dbg.img
264
265       This will create an initramfs with the strace, fsck.ext3 and ssh
266       executables, together with the libraries needed to start those. The
267       --install option can be specified multiple times.
268
269   Network Boot
270       If your root partition is on a network drive, you have to have the
271       network dracut modules installed to create a network aware initramfs
272       image.
273
274       If you specify ip=dhcp on the kernel command line, then dracut asks a
275       dhcp server about the ip address for the machine. The dhcp server can
276       also serve an additional root-path, which will set the root device for
277       dracut. With this mechanism, you have static configuration on your
278       client machine and a centralized boot configuration on your TFTP/DHCP
279       server. If you can’t pass a kernel command line, then you can inject
280       /etc/cmdline.d/mycmdline.conf, with a method described in the section
281       called “Injecting custom Files”.
282
283       Reducing the Image Size
284           To reduce the size of the initramfs, you should create it with by
285           omitting all dracut modules, which you know, you don’t need to boot
286           the machine.
287
288           You can also specify the exact dracut and kernel modules to produce
289           a very tiny initramfs image.
290
291           For example for a NFS image, you would do:
292
293               # dracut -m "nfs network base" initramfs-nfs-only.img
294
295           Then you would boot from this image with your target machine and
296           reduce the size once more by creating it on the target machine with
297           the --host-only option:
298
299               # dracut -m "nfs network base" --host-only initramfs-nfs-host-only.img
300
301           This will reduce the size of the initramfs image significantly.
302

TROUBLESHOOTING

304       If the boot process does not succeed, you have several options to debug
305       the situation.
306
307   Identifying your problem area
308        1. Remove 'rhgb' and 'quiet' from the kernel command line
309
310        2. Add 'rd.shell' to the kernel command line. This will present a
311           shell should dracut be unable to locate your root device
312
313        3. Add 'rd.shell rd.debug log_buf_len=1M' to the kernel command line
314           so that dracut shell commands are printed as they are executed
315
316        4. The file /run/initramfs/rdsosreport.txt is generated, which
317           contains all the logs and the output of all significant tools,
318           which are mentioned later.
319
320       If you want to save that output, simply mount /boot by hand or insert
321       an USB stick and mount that. Then you can store the output for later
322       inspection.
323
324   Information to include in your report
325       All bug reports
326           In all cases, the following should be mentioned and attached to
327           your bug report:
328
329           •   The exact kernel command-line used. Typically from the
330               bootloader configuration file (e.g.  /boot/grub2/grub.cfg) or
331               from /proc/cmdline.
332
333           •   A copy of your disk partition information from /etc/fstab,
334               which might be obtained booting an old working initramfs or a
335               rescue medium.
336
337           •   Turn on dracut debugging (see the debugging dracut section),
338               and attach the file /run/initramfs/rdsosreport.txt.
339
340           •   If you use a dracut configuration file, please include
341               /etc/dracut.conf and all files in /etc/dracut.conf.d/*.conf
342
343       Network root device related problems
344           This section details information to include when experiencing
345           problems on a system whose root device is located on a network
346           attached volume (e.g. iSCSI, NFS or NBD). As well as the
347           information from the section called “All bug reports”, include the
348           following information:
349
350           •   Please include the output of
351
352                   # /sbin/ifup <interfacename>
353                   # ip addr show
354
355   Debugging dracut
356       Configure a serial console
357           Successfully debugging dracut will require some form of console
358           logging during the system boot. This section documents configuring
359           a serial console connection to record boot messages.
360
361            1. First, enable serial console output for both the kernel and the
362               bootloader.
363
364            2. Open the file /boot/grub2/grub.cfg for editing. Below the line
365               'timeout=5', add the following:
366
367                   serial --unit=0 --speed=9600
368                   terminal --timeout=5 serial console
369
370            3. Also in /boot/grub2/grub.cfg, add the following boot arguments
371               to the 'kernel' line:
372
373                   console=tty0 console=ttyS0,9600
374
375            4. When finished, the /boot/grub2/grub.cfg file should look
376               similar to the example below.
377
378                   default=0
379                   timeout=5
380                   serial --unit=0 --speed=9600
381                   terminal --timeout=5 serial console
382                   title Fedora (2.6.29.5-191.fc11.x86_64)
383                     root (hd0,0)
384                     kernel /vmlinuz-2.6.29.5-191.fc11.x86_64 ro root=/dev/mapper/vg_uc1-lv_root console=tty0 console=ttyS0,9600
385                     initrd /dracut-2.6.29.5-191.fc11.x86_64.img
386
387            5. More detailed information on how to configure the kernel for
388               console output can be found at
389               http://www.faqs.org/docs/Linux-HOWTO/Remote-Serial-Console-HOWTO.html#CONFIGURE-KERNEL.
390
391            6. Redirecting non-interactive output
392
393                   Note
394                   You can redirect all non-interactive output to /dev/kmsg
395                   and the kernel will put it out on the console when it
396                   reaches the kernel buffer by doing
397
398                   # exec >/dev/kmsg 2>&1 </dev/console
399
400       Using the dracut shell
401           dracut offers a shell for interactive debugging in the event dracut
402           fails to locate your root filesystem. To enable the shell:
403
404            1. Add the boot parameter 'rd.shell' to your bootloader
405               configuration file (e.g.  /boot/grub2/grub.cfg)
406
407            2. Remove the boot arguments 'rhgb' and 'quiet'
408
409               A sample /boot/grub2/grub.cfg bootloader configuration file is
410               listed below.
411
412                   default=0
413                   timeout=5
414                   serial --unit=0 --speed=9600
415                   terminal --timeout=5 serial console
416                   title Fedora (2.6.29.5-191.fc11.x86_64)
417                     root (hd0,0)
418                     kernel /vmlinuz-2.6.29.5-191.fc11.x86_64 ro root=/dev/mapper/vg_uc1-lv_root console=tty0 rd.shell
419                     initrd /dracut-2.6.29.5-191.fc11.x86_64.img
420
421            3. If system boot fails, you will be dropped into a shell as seen
422               in the example below.
423
424                   No root device found
425                   Dropping to debug shell.
426
427                   #
428
429            4. Use this shell prompt to gather the information requested above
430               (see the section called “All bug reports”).
431
432       Accessing the root volume from the dracut shell
433           From the dracut debug shell, you can manually perform the task of
434           locating and preparing your root volume for boot. The required
435           steps will depend on how your root volume is configured. Common
436           scenarios include:
437
438           •   A block device (e.g.  /dev/sda7)
439
440           •   A LVM logical volume (e.g.  /dev/VolGroup00/LogVol00)
441
442           •   An encrypted device (e.g.
443               /dev/mapper/luks-4d5972ea-901c-4584-bd75-1da802417d83)
444
445           •   A network attached device (e.g.
446               netroot=iscsi:@192.168.0.4::3260::iqn.2009-02.org.example:for.all)
447
448           The exact method for locating and preparing will vary. However, to
449           continue with a successful boot, the objective is to locate your
450           root volume and create a symlink /dev/root which points to the file
451           system. For example, the following example demonstrates accessing
452           and booting a root volume that is an encrypted LVM Logical volume.
453
454            1. Inspect your partitions using parted
455
456                   # parted /dev/sda -s p
457                   Model: ATA HTS541060G9AT00 (scsi)
458                   Disk /dev/sda: 60.0GB
459                   Sector size (logical/physical): 512B/512B
460                   Partition Table: msdos
461                   Number  Start   End     Size    Type      File system  Flags
462                   1      32.3kB  10.8GB  107MB   primary   ext4         boot
463                   2      10.8GB  55.6GB  44.7GB  logical                lvm
464
465            2. You recall that your root volume was a LVM logical volume. Scan
466               and activate any logical volumes.
467
468                   # lvm vgscan
469                   # lvm vgchange -ay
470
471            3. You should see any logical volumes now using the command blkid:
472
473                   # blkid
474                   /dev/sda1: UUID="3de247f3-5de4-4a44-afc5-1fe179750cf7" TYPE="ext4"
475                   /dev/sda2: UUID="Ek4dQw-cOtq-5MJu-OGRF-xz5k-O2l8-wdDj0I" TYPE="LVM2_member"
476                   /dev/mapper/linux-root: UUID="def0269e-424b-4752-acf3-1077bf96ad2c" TYPE="crypto_LUKS"
477                   /dev/mapper/linux-home: UUID="c69127c1-f153-4ea2-b58e-4cbfa9257c5e" TYPE="ext3"
478                   /dev/mapper/linux-swap: UUID="47b4d329-975c-4c08-b218-f9c9bf3635f1" TYPE="swap"
479
480            4. From the output above, you recall that your root volume exists
481               on an encrypted block device. Following the guidance disk
482               encryption guidance from the Installation Guide, you unlock
483               your encrypted root volume.
484
485                   # UUID=$(cryptsetup luksUUID /dev/mapper/linux-root)
486                   # cryptsetup luksOpen /dev/mapper/linux-root luks-$UUID
487                   Enter passphrase for /dev/mapper/linux-root:
488                   Key slot 0 unlocked.
489
490            5. Next, make a symbolic link to the unlocked root volume
491
492                   # ln -s /dev/mapper/luks-$UUID /dev/root
493
494            6. With the root volume available, you may continue booting the
495               system by exiting the dracut shell
496
497                   # exit
498
499       Additional dracut boot parameters
500           For more debugging options, see dracut.cmdline(7).
501
502       Debugging dracut on shutdown
503           To debug the shutdown sequence on systemd systems, you can rd.break
504           on pre-shutdown or shutdown.
505
506           To do this from an already booted system:
507
508               # mkdir -p /run/initramfs/etc/cmdline.d
509               # echo "rd.debug rd.break=pre-shutdown rd.break=shutdown" > /run/initramfs/etc/cmdline.d/debug.conf
510               # touch /run/initramfs/.need_shutdown
511
512           This will give you a dracut shell after the system pivot’ed back in
513           the initramfs.
514

OPTIONS

516       --kver <kernel version>
517           Set the kernel version. This enables to specify the kernel version,
518           without specifying the location of the initramfs image. For
519           example:
520
521           # dracut --kver 3.5.0-0.rc7.git1.2.fc18.x86_64
522
523       -f, --force
524           Overwrite existing initramfs file.
525
526       <output file> --rebuild
527           Append the current arguments to those with which the input
528           initramfs image was built. This option helps in incrementally
529           building the initramfs for testing. If optional <output file> is
530           not provided, the input initramfs provided to rebuild will be used
531           as output file.
532
533       -a, --add <list of dracut modules>
534           Add a space-separated list of dracut modules to the default set of
535           modules. This parameter can be specified multiple times.
536
537               Note
538               If the list has multiple arguments, then you have to put these
539               in quotes. For example:
540
541                   # dracut --add "module1 module2"  ...
542
543       --force-add <list of dracut modules>
544           Force to add a space-separated list of dracut modules to the
545           default set of modules, when -H is specified. This parameter can be
546           specified multiple times.
547
548               Note
549               If the list has multiple arguments, then you have to put these
550               in quotes. For example:
551
552                   # dracut --force-add "module1 module2"  ...
553
554       -o, --omit <list of dracut modules>
555           Omit a space-separated list of dracut modules. This parameter can
556           be specified multiple times.
557
558               Note
559               If the list has multiple arguments, then you have to put these
560               in quotes. For example:
561
562                   # dracut --omit "module1 module2"  ...
563
564       -m, --modules <list of dracut modules>
565           Specify a space-separated list of dracut modules to call when
566           building the initramfs. Modules are located in
567           /usr/lib/dracut/modules.d. This parameter can be specified multiple
568           times. This option forces dracut to only include the specified
569           dracut modules. In most cases the "--add" option is what you want
570           to use.
571
572               Note
573               If the list has multiple arguments, then you have to put these
574               in quotes. For example:
575
576                   # dracut --modules "module1 module2"  ...
577
578       -d, --drivers <list of kernel modules>
579           Specify a space-separated list of kernel modules to exclusively
580           include in the initramfs. The kernel modules have to be specified
581           without the ".ko" suffix. This parameter can be specified multiple
582           times.
583
584               Note
585               If the list has multiple arguments, then you have to put these
586               in quotes. For example:
587
588                   # dracut --drivers "kmodule1 kmodule2"  ...
589
590       --add-drivers <list of kernel modules>
591           Specify a space-separated list of kernel modules to add to the
592           initramfs. The kernel modules have to be specified without the
593           ".ko" suffix. This parameter can be specified multiple times.
594
595               Note
596               If the list has multiple arguments, then you have to put these
597               in quotes. For example:
598
599                   # dracut --add-drivers "kmodule1 kmodule2"  ...
600
601       --force-drivers <list of kernel modules>
602           See add-drivers above. But in this case it is ensured that the
603           drivers are tried to be loaded early via modprobe.
604
605               Note
606               If the list has multiple arguments, then you have to put these
607               in quotes. For example:
608
609                   # dracut --force-drivers "kmodule1 kmodule2"  ...
610
611       --omit-drivers <list of kernel modules>
612           Specify a space-separated list of kernel modules not to add to the
613           initramfs. The kernel modules have to be specified without the
614           ".ko" suffix. This parameter can be specified multiple times.
615
616               Note
617               If the list has multiple arguments, then you have to put these
618               in quotes. For example:
619
620                   # dracut --omit-drivers "kmodule1 kmodule2"  ...
621
622       --filesystems <list of filesystems>
623           Specify a space-separated list of kernel filesystem modules to
624           exclusively include in the generic initramfs. This parameter can be
625           specified multiple times.
626
627               Note
628               If the list has multiple arguments, then you have to put these
629               in quotes. For example:
630
631                   # dracut --filesystems "filesystem1 filesystem2"  ...
632
633       -k, --kmoddir <kernel directory>
634           Specify the directory, where to look for kernel modules.
635
636       --fwdir <dir>[:<dir>...]++
637           Specify additional directories, where to look for firmwares. This
638           parameter can be specified multiple times.
639
640       --libdirs <list of directories>
641           Specify a space-separated list of directories to look for libraries
642           to include in the generic initramfs. This parameter can be
643           specified multiple times.
644
645               Note
646               If the list has multiple arguments, then you have to put these
647               in quotes. For example:
648
649                   # dracut --libdirs "dir1 dir2"  ...
650
651       --kernel-cmdline <parameters>
652           Specify default kernel command line parameters.
653
654       --kernel-only
655           Only install kernel drivers and firmware files.
656
657       --no-kernel
658           Do not install kernel drivers and firmware files.
659
660       --early-microcode
661           Combine early microcode with ramdisk.
662
663       --no-early-microcode
664           Do not combine early microcode with ramdisk.
665
666       --print-cmdline
667           Print the kernel command line for the current disk layout.
668
669       --mdadmconf
670           Include local /etc/mdadm.conf file.
671
672       --nomdadmconf
673           Do not include local /etc/mdadm.conf file.
674
675       --lvmconf
676           Include local /etc/lvm/lvm.conf file.
677
678       --nolvmconf
679           Do not include local /etc/lvm/lvm.conf file.
680
681       --fscks <list of fsck tools>
682           Add a space-separated list of fsck tools, in addition to
683           dracut.conf's specification; the installation is opportunistic
684           (non-existing tools are ignored).
685
686               Note
687               If the list has multiple arguments, then you have to put these
688               in quotes. For example:
689
690                   # dracut --fscks "fsck.foo barfsck"  ...
691
692       --nofscks
693           Inhibit installation of any fsck tools.
694
695       --strip
696           Strip binaries in the initramfs (default).
697
698       --aggressive-strip
699           Strip more than just debug symbol and sections, for a smaller
700           initramfs build. The --strip option must also be specified.
701
702       --nostrip
703           Do not strip binaries in the initramfs.
704
705       --hardlink
706           Hardlink files in the initramfs (default).
707
708       --nohardlink
709           Do not hardlink files in the initramfs.
710
711       --prefix <dir>
712           Prefix initramfs files with the specified directory.
713
714       --noprefix
715           Do not prefix initramfs files (default).
716
717       -h, --help
718           Display help text and exit.
719
720       --debug
721           Output debug information of the build process.
722
723       -v, --verbose
724           Increase verbosity level (default is info(4)).
725
726       --version
727           Display version and exit.
728
729       -q, --quiet
730           Decrease verbosity level (default is info(4)).
731
732       -c, --conf <dracut configuration file>
733           Specify configuration file to use.
734
735           Default: /etc/dracut.conf
736
737       --confdir <configuration directory>
738           Specify configuration directory to use.
739
740           Default: /etc/dracut.conf.d
741
742       --tmpdir <temporary directory>
743           Specify temporary directory to use.
744
745           Default: /var/tmp
746
747       -r, --sysroot <sysroot directory>
748           Specify the sysroot directory to collect files from. This is useful
749           to create the initramfs image from a cross-compiled sysroot
750           directory. For the extra helper variables, see ENVIRONMENT below.
751
752           Default: empty
753
754       --sshkey <sshkey file>
755           SSH key file used with ssh-client module.
756
757       --logfile <logfile>
758           Logfile to use; overrides any setting from the configuration files.
759
760           Default: /var/log/dracut.log
761
762       -l, --local
763           Activates the local mode. dracut will use modules from the current
764           working directory instead of the system-wide installed modules in
765           /usr/lib/dracut/modules.d. This is useful when running dracut from
766           a git checkout.
767
768       -H, --hostonly
769           Host-only mode: Install only what is needed for booting the local
770           host instead of a generic host and generate host-specific
771           configuration.
772
773               Warning
774               If chrooted to another root other than the real root device,
775               use "--fstab" and provide a valid /etc/fstab.
776
777       -N, --no-hostonly
778           Disable host-only mode.
779
780       --hostonly-mode <mode>
781           Specify the host-only mode to use.  <mode> could be one of "sloppy"
782           or "strict". In "sloppy" host-only mode, extra drivers and modules
783           will be installed, so minor hardware change won’t make the image
784           unbootable (e.g. changed keyboard), and the image is still portable
785           among similar hosts. With "strict" mode enabled, anything not
786           necessary for booting the local host in its current state will not
787           be included, and modules may do some extra job to save more space.
788           Minor change of hardware or environment could make the image
789           unbootable.
790
791           Default: sloppy
792
793       --hostonly-cmdline
794           Store kernel command line arguments needed in the initramfs.
795
796       --no-hostonly-cmdline
797           Do not store kernel command line arguments needed in the initramfs.
798
799       --no-hostonly-default-device
800           Do not generate implicit host devices like root, swap, fstab, etc.
801           Use "--mount" or "--add-device" to explicitly add devices as
802           needed.
803
804       --hostonly-i18n
805           Install only needed keyboard and font files according to the host
806           configuration (default).
807
808       --no-hostonly-i18n
809           Install all keyboard and font files available.
810
811       --hostonly-nics <list of nics>
812           Only enable listed NICs in the initramfs. The list can be empty, so
813           other modules can install only the necessary network drivers.
814
815       --persistent-policy <policy>
816           Use <policy> to address disks and partitions.  <policy> can be any
817           directory name found in /dev/disk (e.g. "by-uuid", "by-label"), or
818           "mapper" to use /dev/mapper device names (default).
819
820       --fstab
821           Use /etc/fstab instead of /proc/self/mountinfo.
822
823       --add-fstab <filename>
824           Add entries of <filename> to the initramfs /etc/fstab.
825
826       --mount "<device> <mountpoint> <filesystem type> [<filesystem options>
827       [<dump frequency> [<fsck order>]]]"
828           Mount <device> on <mountpoint> with <filesystem type> in the
829           initramfs.  <filesystem options>, <dump options> and <fsck order>
830           can be specified, see fstab manpage for the details. The default
831           <filesystem options> is "defaults". The default <dump frequency> is
832           "0". The default <fsck order> is "2".
833
834       --mount "<mountpoint>"
835           Like above, but <device>, <filesystem type> and <filesystem
836           options> are determined by looking at the current mounts.
837
838       --add-device <device>
839           Bring up <device> in initramfs, <device> should be the device name.
840           This can be useful in host-only mode for resume support when your
841           swap is on LVM or an encrypted partition. [NB --device can be used
842           for compatibility with earlier releases]
843
844       -i, --include <SOURCE> <TARGET>
845           Include the files in the SOURCE directory into the TARGET directory
846           in the final initramfs. If SOURCE is a file, it will be installed
847           to TARGET in the final initramfs. This parameter can be specified
848           multiple times.
849
850       -I, --install <file list>
851           Install the space separated list of files into the initramfs.
852
853               Note
854               If the list has multiple arguments, then you have to put these
855               in quotes. For example:
856
857                   # dracut --install "/bin/foo /sbin/bar"  ...
858
859       --install-optional <file list>
860           Install the space separated list of files into the initramfs, if
861           they exist.
862
863       --gzip
864           Compress the generated initramfs using gzip. This will be done by
865           default, unless another compression option or --no-compress is
866           passed. Equivalent to "--compress=gzip -9".
867
868       --bzip2
869           Compress the generated initramfs using bzip2.
870
871               Warning
872               Make sure your kernel has bzip2 decompression support compiled
873               in, otherwise you will not be able to boot. Equivalent to
874               "--compress=bzip2 -9".
875
876       --lzma
877           Compress the generated initramfs using lzma.
878
879               Warning
880               Make sure your kernel has lzma decompression support compiled
881               in, otherwise you will not be able to boot. Equivalent to
882               "--compress=lzma -9 -T0".
883
884       --xz
885           Compress the generated initramfs using xz.
886
887               Warning
888               Make sure your kernel has xz decompression support compiled in,
889               otherwise you will not be able to boot. Equivalent to
890               "--compress=xz --check=crc32 --lzma2=dict=1MiB -T0".
891
892       --lzo
893           Compress the generated initramfs using lzop.
894
895               Warning
896               Make sure your kernel has lzo decompression support compiled
897               in, otherwise you will not be able to boot. Equivalent to
898               "--compress=lzop -9".
899
900       --lz4
901           Compress the generated initramfs using lz4.
902
903               Warning
904               Make sure your kernel has lz4 decompression support compiled
905               in, otherwise you will not be able to boot. Equivalent to
906               "--compress=lz4 -l -9".
907
908       --zstd
909           Compress the generated initramfs using Zstandard.
910
911               Warning
912               Make sure your kernel has zstd decompression support compiled
913               in, otherwise you will not be able to boot. Equivalent to
914               "--compress=zstd -15 -q -T0".
915
916       --compress <compressor>
917           Compress the generated initramfs using the passed compression
918           program. If you pass it just the name of a compression program, it
919           will call that program with known-working arguments. If you pass a
920           quoted string with arguments, it will be called with exactly those
921           arguments. Depending on what you pass, this may result in an
922           initramfs that the kernel cannot decompress. The default value can
923           also be set via the INITRD_COMPRESS environment variable.
924
925       --squash-compressor <compressor>
926           Compress the squashfs image using the passed compressor and
927           compressor specific options for mksquashfs. You can refer to
928           mksquashfs manual for supported compressors and compressor specific
929           options. If squash module is not called when building the
930           initramfs, this option will not take effect.
931
932       --no-compress
933           Do not compress the generated initramfs. This will override any
934           other compression options.
935
936       --reproducible
937           Create reproducible images.
938
939       --no-reproducible
940           Do not create reproducible images.
941
942       --list-modules
943           List all available dracut modules.
944
945       -M, --show-modules
946           Print included module’s name to standard output during build.
947
948       --keep
949           Keep the initramfs temporary directory for debugging purposes.
950
951       --printsize
952           Print out the module install size.
953
954       --profile
955           Output profile information of the build process.
956
957       --ro-mnt
958           Mount / and /usr read-only by default.
959
960       -L, --stdlog <level>
961           [0-6] Specify logging level (to standard error).
962
963                     0 - suppress any messages
964                     1 - only fatal errors
965                     2 - all errors
966                     3 - warnings
967                     4 - info
968                     5 - debug info (here starts lots of output)
969                     6 - trace info (and even more)
970
971       --regenerate-all
972           Regenerate all initramfs images at the default location with the
973           kernel versions found on the system. Additional parameters are
974           passed through.
975
976       -p, --parallel
977           Try to execute tasks in parallel. Currently only supported with
978           --regenerate-all (build initramfs images for all kernel versions
979           simultaneously).
980
981       --noimageifnotneeded
982           Do not create an image in host-only mode, if no kernel driver is
983           needed and no /etc/cmdline/*.conf will be generated into the
984           initramfs.
985
986       --loginstall <directory>
987           Log all files installed from the host to <directory>.
988
989       --uefi
990           Instead of creating an initramfs image, dracut will create an UEFI
991           executable, which can be executed by an UEFI BIOS. The default
992           output filename is
993           <EFI>/EFI/Linux/linux-$kernel$-<MACHINE_ID>-<BUILD_ID>.efi. <EFI>
994           might be /efi, /boot or /boot/efi depending on where the ESP
995           partition is mounted. The <BUILD_ID> is taken from BUILD_ID in
996           /usr/lib/os-release or if it exists /etc/os-release and is left
997           out, if BUILD_ID is non-existant or empty.
998
999       --no-uefi
1000           Disables UEFI mode.
1001
1002       --no-machineid
1003           Affects the default output filename of --uefi and will discard the
1004           <MACHINE_ID> part.
1005
1006       --uefi-stub <file>
1007           Specifies the UEFI stub loader, which will load the attached
1008           kernel, initramfs and kernel command line and boots the kernel. The
1009           default is
1010           $prefix/lib/systemd/boot/efi/linux<EFI-MACHINE-TYPE-NAME>.efi.stub.
1011
1012       --uefi-splash-image <file>
1013           Specifies the UEFI stub loader’s splash image. Requires bitmap
1014           (.bmp) image format.
1015
1016       --kernel-image <file>
1017           Specifies the kernel image, which to include in the UEFI
1018           executable. The default is /lib/modules/<KERNEL-VERSION>/vmlinuz or
1019           /boot/vmlinuz-<KERNEL-VERSION>.
1020
1021       --enhanced-cpio
1022           Attempt to use the dracut-cpio binary, which optimizes archive
1023           creation for copy-on-write filesystems by using the
1024           copy_file_range(2) syscall via Rust’s io::copy(). When specified,
1025           initramfs archives are also padded to ensure optimal data alignment
1026           for extent sharing. To retain reflink data deduplication benefits,
1027           this should be used alongside the --no-compress and --nostrip
1028           parameters, with initramfs source files, --tmpdir staging area and
1029           destination all on the same copy-on-write capable filesystem.
1030

ENVIRONMENT

1032       INITRD_COMPRESS
1033           sets the default compression program. See --compress.
1034
1035       DRACUT_LDCONFIG
1036           sets the ldconfig program path and options. Optional. Used for
1037           --sysroot.
1038
1039           Default: ldconfig
1040
1041       DRACUT_LDD
1042           sets the ldd program path and options. Optional. Used for
1043           --sysroot.
1044
1045           Default: ldd
1046
1047       DRACUT_TESTBIN
1048           sets the initially tested binary for detecting library paths.
1049           Optional. Used for --sysroot. In the cross-compiled sysroot, the
1050           default value (/bin/sh) is unusable, as it is an absolute symlink
1051           and points outside the sysroot directory.
1052
1053           Default: /bin/sh
1054
1055       DRACUT_INSTALL
1056           overrides path and options for executing dracut-install internally.
1057           Optional. Can be used to debug dracut-install while running the
1058           main dracut script.
1059
1060           Default: dracut-install
1061
1062           Example: DRACUT_INSTALL="valgrind dracut-install"
1063
1064       DRACUT_COMPRESS_BZIP2, DRACUT_COMPRESS_BZIP2, DRACUT_COMPRESS_LBZIP2,
1065       DRACUT_COMPRESS_LZMA, DRACUT_COMPRESS_XZ, DRACUT_COMPRESS_GZIP,
1066       DRACUT_COMPRESS_PIGZ, DRACUT_COMPRESS_LZOP, DRACUT_COMPRESS_ZSTD,
1067       DRACUT_COMPRESS_LZ4, DRACUT_COMPRESS_CAT
1068           overrides for compression utilities to support using them from
1069           non-standard paths.
1070
1071           Default values are the default compression utility names to be
1072           found in PATH.
1073
1074       DRACUT_ARCH
1075           overrides the value of uname -m. Used for --sysroot.
1076
1077           Default: empty (the value of uname -m on the host system)
1078
1079       SYSTEMD_VERSION
1080           overrides systemd version. Used for --sysroot.
1081
1082       SYSTEMCTL
1083           overrides the systemctl binary. Used for --sysroot.
1084
1085       NM_VERSION
1086           overrides the NetworkManager version. Used for --sysroot.
1087
1088       DRACUT_INSTALL_PATH
1089           overrides PATH environment for dracut-install to look for binaries
1090           relative to --sysroot. In a cross-compiled environment (e.g.
1091           Yocto), PATH points to natively built binaries that are not in the
1092           host’s /bin, /usr/bin, etc.  dracut-install still needs plain /bin
1093           and /usr/bin that are relative to the cross-compiled sysroot.
1094
1095           Default: PATH
1096
1097       DRACUT_INSTALL_LOG_TARGET
1098           overrides DRACUT_LOG_TARGET for dracut-install. It allows running
1099           dracut-install* to run with different log target that dracut** runs
1100           with.
1101
1102           Default: DRACUT_LOG_TARGET
1103
1104       DRACUT_INSTALL_LOG_LEVEL
1105           overrides DRACUT_LOG_LEVEL for dracut-install. It allows running
1106           dracut-install* to run with different log level that dracut** runs
1107           with.
1108
1109           Default: DRACUT_LOG_LEVEL
1110

FILES

1112       /var/log/dracut.log
1113           logfile of initramfs image creation
1114
1115       /tmp/dracut.log
1116           logfile of initramfs image creation, if /var/log/dracut.log is not
1117           writable
1118
1119       /etc/dracut.conf
1120           see dracut.conf5
1121
1122       /etc/dracut.conf.d/*.conf
1123           see dracut.conf5
1124
1125       /usr/lib/dracut/dracut.conf.d/*.conf
1126           see dracut.conf5
1127
1128   Configuration in the initramfs
1129       /etc/conf.d/
1130           Any files found in /etc/conf.d/ will be sourced in the initramfs to
1131           set initial values. Command line options will override these values
1132           set in the configuration files.
1133
1134       /etc/cmdline
1135           Can contain additional command line options. Deprecated, better use
1136           /etc/cmdline.d/*.conf.
1137
1138       /etc/cmdline.d/*.conf
1139           Can contain additional command line options.
1140

AVAILABILITY

1142       The dracut command is part of the dracut package and is available from
1143       https://github.com/dracutdevs/dracut
1144

AUTHORS

1146       Harald Hoyer
1147
1148       Victor Lowther
1149
1150       Amadeusz Żołnowski
1151
1152       Hannes Reinecke
1153
1154       Daniel Molkentin
1155
1156       Will Woods
1157
1158       Philippe Seewer
1159
1160       Warren Togami
1161

SEE ALSO

1163       dracut.cmdline(7) dracut.conf(5) lsinitrd(1)
1164
1165
1166
1167dracut 44b18de                    11/16/2023                         DRACUT(8)
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