DRACUT(8) ========= :doctype: manpage :man source: dracut :man manual: dracut NAME ---- dracut - low-level tool for generating an initramfs image SYNOPSIS -------- *dracut* ['OPTION...'] [ [__]] DESCRIPTION ----------- Create an initramfs for the kernel with the version . If is omitted, then the version of the actual running kernel is used. If is omitted or empty, then the default location /boot/initramfs-.img is used. dracut creates an initial image used by the kernel for preloading the block device modules (such as IDE, SCSI or RAID) which are needed to access the root filesystem, mounting the root filesystem and booting into the real system. At boot time, the kernel unpacks that archive into RAM disk, mounts and uses it as initial root file system. All finding of the root device happens in this early userspace. For a complete list of kernel command line options see *dracut.cmdline*(7). If you are dropped to an emergency shell, while booting your initramfs, the file _/run/initramfs/sosreport.txt_ is created, which can be safed to a (to be mounted by hand) partition (usually /boot) or a USB stick. Additional debugging info can be produced by adding **rd.debug** to the kernel command line. _/run/initramfs/sosreport.txt_ contains all logs and the output of some tools. It should be attached to any report about dracut problems. EXAMPLE ------- To create a initramfs image, the most simple command is: ---- # dracut ---- This will generate a general purpose initramfs image, with all possible functionality resulting of the combination of the installed dracut modules and system tools. The image is /boot/initramfs-_++++_.img and contains the kernel modules of the currently active kernel with version _++++_. If the initramfs image already exists, dracut will display an error message, and to overwrite the existing image, you have to use the --force option. ---- # dracut --force ---- If you want to specify another filename for the resulting image you would issue a command like: ---- # dracut foobar.img ---- To generate an image for a specific kernel version, the command would be: ---- # dracut foobar.img 2.6.40-1.rc5.f20 ---- A shortcut to generate the image at the default location for a specific kernel version is: ---- # dracut --kver 2.6.40-1.rc5.f20 ---- If you want to create lighter, smaller initramfs images, you may want to specify the --host-only or -H option. Using this option, the resulting image will contain only those dracut modules, kernel modules and filesystems, which are needed to boot this specific machine. This has the drawback, that you can't put the disk on another controller or machine, and that you can't switch to another root filesystem, without recreating the initramfs image. The usage of the --host-only option is only for experts and you will have to keep the broken pieces. At least keep a copy of a general purpose image (and corresponding kernel) as a fallback to rescue your system. OPTIONS ------- **--kver** __:: set the kernel version. This enables to specify the kernel version, without specifying the location of the initramfs image. For example: ---- # dracut --kver 3.5.0-0.rc7.git1.2.fc18.x86_64 ---- **-f, --force**:: overwrite existing initramfs file. **-m, --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 parameter can be specified multiple times. + [NOTE] =============================== If [LIST] has multiple arguments, then you have to put these in quotes. For example: ---- # dracut --modules "module1 module2" ... ---- =============================== **-o, --omit** __:: omit a space-separated list of dracut modules. This parameter can be specified multiple times. + [NOTE] =============================== If [LIST] has multiple arguments, then you have to put these in quotes. For example: ---- # dracut --omit "module1 module2" ... ---- =============================== **-a, --add** __:: add a space-separated list of dracut modules to the default set of modules. This parameter can be specified multiple times. + [NOTE] =============================== If [LIST] has multiple arguments, then you have to put these in quotes. For example: ---- # dracut --add "module1 module2" ... ---- =============================== **--force-add** __:: force to add a space-separated list of dracut modules to the default set of modules, when -H is specified. This parameter can be specified multiple times. + [NOTE] =============================== If [LIST] has multiple arguments, then you have to put these in quotes. For example: ---- # dracut --force-add "module1 module2" ... ---- =============================== **-d, --drivers** __:: specify a space-separated list of kernel modules to exclusively include in the initramfs. The kernel modules have to be specified without the ".ko" suffix. This parameter can be specified multiple times. + [NOTE] =============================== If [LIST] has multiple arguments, then you have to put these in quotes. For example: ---- # dracut --drivers "kmodule1 kmodule2" ... ---- =============================== **--add-drivers** __:: specify a space-separated list of kernel modules to add to the initramfs. The kernel modules have to be specified without the ".ko" suffix. This parameter can be specified multiple times. + [NOTE] =============================== If [LIST] has multiple arguments, then you have to put these in quotes. For example: ---- # dracut --add-drivers "kmodule1 kmodule2" ... ---- =============================== **--omit-drivers** __:: specify a space-separated list of kernel modules not to add to the initramfs. The kernel modules have to be specified without the ".ko" suffix. This parameter can be specified multiple times. + [NOTE] =============================== If [LIST] has multiple arguments, then you have to put these in quotes. For example: ---- # dracut --omit-drivers "kmodule1 kmodule2" ... ---- =============================== **--filesystems** __:: specify a space-separated list of kernel filesystem modules to exclusively include in the generic initramfs. This parameter can be specified multiple times. + [NOTE] =============================== If [LIST] has multiple arguments, then you have to put these in quotes. For example: ---- # dracut --filesystems "filesystem1 filesystem2" ... ---- =============================== **-k, --kmoddir** __:: specify the directory, where to look for kernel modules **--fwdir** _[:...]++_:: specify additional directories, where to look for firmwares. This parameter can be specified multiple times. **--kernel-cmdline **:: specify default kernel command line parameters **--kernel-only**:: only install kernel drivers and firmware files **--no-kernel**:: do not install kernel drivers and firmware files **--mdadmconf**:: include local _/etc/mdadm.conf_ **--nomdadmconf**:: do not include local _/etc/mdadm.conf_ **--lvmconf**:: include local _/etc/lvm/lvm.conf_ **--nolvmconf**:: do not include local _/etc/lvm/lvm.conf_ **--fscks** [LIST]:: add a space-separated list of fsck tools, in addition to _dracut.conf_'s specification; the installation is opportunistic (non-existing tools are ignored) + [NOTE] =============================== If [LIST] has multiple arguments, then you have to put these in quotes. For example: ---- # dracut --fscks "fsck.foo barfsck" ... ---- =============================== **--nofscks**:: inhibit installation of any fsck tools **--strip**:: strip binaries in the initramfs (default) **--nostrip**:: do not strip binaries in the initramfs **--hardlink**:: hardlink files in the initramfs (default) **--nohardlink**:: do not hardlink files in the initramfs **--prefix** __:: prefix initramfs files with the specified directory **--noprefix**:: do not prefix initramfs files (default) **-h, --help**:: display help text and exit. **--debug**:: output debug information of the build process **-v, --verbose**:: increase verbosity level (default is info(4)) **-q, --quiet**:: decrease verbosity level (default is info(4)) **-c, --conf** __:: specify configuration file to use. + Default: _/etc/dracut.conf_ **--confdir** __:: specify configuration directory to use. + Default: _/etc/dracut.conf.d_ **--tmpdir** __:: specify temporary directory to use. + Default: _/var/tmp_ **--sshkey** __:: ssh key file used with ssh-client module. **-l, --local**:: activates the local mode. dracut will use modules from the current working directory instead of the system-wide installed modules in _/usr/lib/dracut/modules.d_. This is useful when running dracut from a git checkout. **-H, --hostonly**:: Host-Only mode: Install only what is needed for booting the local host instead of a generic host and generate host-specific configuration. + [WARNING] ==== If chrooted to another root other than the real root device, use "--fstab" and provide a valid _/etc/fstab_. ==== **-N, --no-hostonly**:: Disable Host-Only mode **--fstab**:: Use _/etc/fstab_ instead of _/proc/self/mountinfo_. **--add-fstab** __ :: Add entries of __ to the initramfs /etc/fstab. **--mount** "__ __ __ __":: Mount __ on __ with __ and __ in the initramfs **--add-device** __ :: Bring up __ in initramfs, __ should be the device name. This can be useful in hostonly mode for resume support when your swap is on LVM or an encrypted partition. [NB --device can be used for compatibility with earlier releases] **-i, --include** __ __:: include the files in the SOURCE directory into the TARGET directory in the final initramfs. If SOURCE is a file, it will be installed to TARGET in the final initramfs. This parameter can be specified multiple times. **-I, --install** __:: install the space separated list of files into the initramfs. + [NOTE] =============================== If [LIST] has multiple arguments, then you have to put these in quotes. For example: ---- # dracut --install "/bin/foo /sbin/bar" ... ---- =============================== **--gzip**:: Compress the generated initramfs using gzip. This will be done by default, unless another compression option or --no-compress is passed. Equivalent to "--compress=gzip -9" **--bzip2**:: Compress the generated initramfs using bzip2. + [WARNING] ==== Make sure your kernel has bzip2 decompression support compiled in, otherwise you will not be able to boot. Equivalent to "--compress=bzip2" ==== **--lzma**:: Compress the generated initramfs using lzma. + [WARNING] ==== Make sure your kernel has lzma decompression support compiled in, otherwise you will not be able to boot. Equivalent to "--compress=lzma -9" ==== **--xz**:: Compress the generated initramfs using xz. + [WARNING] ==== Make sure your kernel has xz decompression support compiled in, otherwise you will not be able to boot. Equivalent to "--compress=xz --check=crc32 --lzma2=dict=1MiB" ==== **--compress** __:: Compress the generated initramfs using the passed compression program. If you pass it just the name of a compression program, it will call that program with known-working arguments. If you pass a quoted string with arguments, it will be called with exactly those arguments. Depending on what you pass, this may result in an initramfs that the kernel cannot decompress. **--no-compress**:: Do not compress the generated initramfs. This will override any other compression options. **--list-modules**:: List all available dracut modules. **-M, --show-modules**:: Print included module's name to standard output during build. **--keep**:: Keep the initramfs temporary directory for debugging purposes. **--regenerate-all**:: Regenerate all initramfs images at the default location with the kernel versions found on the system. Additional parameters are passed through. FILES ----- _/var/log/dracut.log_:: logfile of initramfs image creation _/tmp/dracut.log_:: logfile of initramfs image creation, if _/var/log/dracut.log_ is not writable _/etc/dracut.conf_:: see dracut.conf5 _/etc/dracut.conf.d/*.conf_:: see dracut.conf5 _/usr/lib/dracut/dracut.conf.d/*.conf_:: see dracut.conf5 Configuration in the initramfs ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ _/etc/conf.d/_:: Any files found in _/etc/conf.d/_ will be sourced in the initramfs to set initial values. Command line options will override these values set in the configuration files. _/etc/cmdline_:: Can contain additional command line options. Deprecated, better use /etc/cmdline.d/*.conf. _/etc/cmdline.d/*.conf:: Can contain additional command line options. AVAILABILITY ------------ The dracut command is part of the dracut package and is available from link:$$https://dracut.wiki.kernel.org$$[https://dracut.wiki.kernel.org] AUTHORS ------- Harald Hoyer Victor Lowther Philippe Seewer Warren Togami Amadeusz Żołnowski Jeremy Katz David Dillow Will Woods SEE ALSO -------- *dracut.cmdline*(7) *dracut.conf*(5)