DRACUT(8) ========= :doctype: manpage :man source: dracut :man manual: dracut :man version: {version} NAME ---- dracut - low-level tool for generating an initramfs/initrd 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, the default location will be determined by the local configuration or Linux distribution policy. 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. Initramfs images are also called "initrd". 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/rdsosreport.txt_ is created, which can be saved 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/rdsosreport.txt_ contains all logs and the output of some tools. It should be attached to any report about dracut problems. USAGE ----- include::dracut.usage.asc[] 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. __ **--rebuild**:: Append the current arguments to those with which the input initramfs image was built. This option helps in incrementally building the initramfs for testing. If optional __ is not provided, the input initramfs provided to rebuild will be used as output file. **-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 the 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 the list has multiple arguments, then you have to put these in quotes. For example: ---- # dracut --force-add "module1 module2" ... ---- =============================== **-o, --omit** __:: Omit a space-separated list of dracut modules. This parameter can be specified multiple times. + [NOTE] =============================== If the list has multiple arguments, then you have to put these in quotes. For example: ---- # dracut --omit "module1 module2" ... ---- =============================== **-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. This option forces dracut to only include the specified dracut modules. In most cases the "--add" option is what you want to use. + [NOTE] =============================== If the list has multiple arguments, then you have to put these in quotes. For example: ---- # dracut --modules "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 the 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 the list has multiple arguments, then you have to put these in quotes. For example: ---- # dracut --add-drivers "kmodule1 kmodule2" ... ---- =============================== **--force-drivers** __:: See add-drivers above. But in this case it is ensured that the drivers are tried to be loaded early via modprobe. + [NOTE] =============================== If the list has multiple arguments, then you have to put these in quotes. For example: ---- # dracut --force-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 the 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 the 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. **--libdirs** __:: Specify a space-separated list of directories to look for libraries to include in the generic initramfs. This parameter can be specified multiple times. + [NOTE] =============================== If the list has multiple arguments, then you have to put these in quotes. For example: ---- # dracut --libdirs "dir1 dir2" ... ---- =============================== **--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. **--early-microcode**:: Combine early microcode with ramdisk. **--no-early-microcode**:: Do not combine early microcode with ramdisk. **--print-cmdline**:: Print the kernel command line for the current disk layout. **--mdadmconf**:: Include local _/etc/mdadm.conf_ file. **--nomdadmconf**:: Do not include local _/etc/mdadm.conf_ file. **--lvmconf**:: Include local _/etc/lvm/lvm.conf_ file. **--nolvmconf**:: Do not include local _/etc/lvm/lvm.conf_ file. **--fscks** __:: 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 the 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). **--aggressive-strip**:: Strip more than just debug symbol and sections, for a smaller initramfs build. The --strip option must also be specified. **--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)). **--version**:: Display version and exit. **-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_ **-r, --sysroot** __:: Specify the sysroot directory to collect files from. This is useful to create the initramfs image from a cross-compiled sysroot directory. For the extra helper variables, see *ENVIRONMENT* below. + Default: _empty_ **--sshkey** __:: SSH key file used with ssh-client module. **--logfile** __:: Logfile to use; overrides any setting from the configuration files. + Default: _/var/log/dracut.log_ **-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. **--hostonly-mode __**:: Specify the host-only mode to use. __ could be one of "sloppy" or "strict". In "sloppy" host-only mode, extra drivers and modules will be installed, so minor hardware change won't make the image unbootable (e.g. changed keyboard), and the image is still portable among similar hosts. With "strict" mode enabled, anything not necessary for booting the local host in its current state will not be included, and modules may do some extra job to save more space. Minor change of hardware or environment could make the image unbootable. + Default: _sloppy_ **--hostonly-cmdline**:: Store kernel command line arguments needed in the initramfs. **--no-hostonly-cmdline**:: Do not store kernel command line arguments needed in the initramfs. **--no-hostonly-default-device**:: Do not generate implicit host devices like root, swap, fstab, etc. Use "--mount" or "--add-device" to explicitly add devices as needed. **--hostonly-i18n**:: Install only needed keyboard and font files according to the host configuration (default). **--no-hostonly-i18n**:: Install all keyboard and font files available. **--hostonly-nics** __:: Only enable listed NICs in the initramfs. The list can be empty, so other modules can install only the necessary network drivers. **--persistent-policy** __:: Use __ to address disks and partitions. __ can be any directory name found in /dev/disk (e.g. "by-uuid", "by-label"), or "mapper" to use /dev/mapper device names (default). **--fstab**:: Use _/etc/fstab_ instead of _/proc/self/mountinfo_. **--add-fstab** __:: Add entries of __ to the initramfs /etc/fstab. **--mount** "__ __ __ [__ [__ [__]]]":: Mount __ on __ with __ in the initramfs. __, __ and __ can be specified, see fstab manpage for the details. The default __ is "defaults". The default __ is "0". The default __ is "2". **--mount** "__":: Like above, but __, __ and __ are determined by looking at the current mounts. **--add-device** __ :: Bring up __ in initramfs, __ should be the device name. This can be useful in host-only 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 the list has multiple arguments, then you have to put these in quotes. For example: ---- # dracut --install "/bin/foo /sbin/bar" ... ---- =============================== **--install-optional** __:: Install the space separated list of files into the initramfs, if they exist. **--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 -9". ==== **--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 -T0". ==== **--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 -T0". ==== **--lzo**:: Compress the generated initramfs using lzop. + [WARNING] ==== Make sure your kernel has lzo decompression support compiled in, otherwise you will not be able to boot. Equivalent to "--compress=lzop -9". ==== **--lz4**:: Compress the generated initramfs using lz4. + [WARNING] ==== Make sure your kernel has lz4 decompression support compiled in, otherwise you will not be able to boot. Equivalent to "--compress=lz4 -l -9". ==== **--zstd**:: Compress the generated initramfs using Zstandard. + [WARNING] ==== Make sure your kernel has zstd decompression support compiled in, otherwise you will not be able to boot. Equivalent to "--compress=zstd -15 -q -T0". ==== **--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. The default value can also be set via the _INITRD_COMPRESS_ environment variable. **--squash-compressor** __:: Compress the squashfs image using the passed compressor and compressor specific options for mksquashfs. You can refer to mksquashfs manual for supported compressors and compressor specific options. If squash module is not called when building the initramfs, this option will not take effect. **--no-compress**:: Do not compress the generated initramfs. This will override any other compression options. **--reproducible**:: Create reproducible images. **--no-reproducible**:: Do not create reproducible images. **--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. **--printsize**:: Print out the module install size. **--profile**:: Output profile information of the build process. **--ro-mnt**:: Mount / and /usr read-only by default. **-L, --stdlog** __:: [0-6] Specify logging level (to standard error). ---- 0 - suppress any messages 1 - only fatal errors 2 - all errors 3 - warnings 4 - info 5 - debug info (here starts lots of output) 6 - trace info (and even more) ---- **--regenerate-all**:: Regenerate all initramfs images at the default location with the kernel versions found on the system. Additional parameters are passed through. **-p, --parallel**:: Try to execute tasks in parallel. Currently only supported with **--regenerate-all** (build initramfs images for all kernel versions simultaneously). **--noimageifnotneeded**:: Do not create an image in host-only mode, if no kernel driver is needed and no /etc/cmdline/*.conf will be generated into the initramfs. **--loginstall __**:: Log all files installed from the host to __. **--uefi**:: Instead of creating an initramfs image, dracut will create an UEFI executable, which can be executed by an UEFI BIOS. The default output filename is _/EFI/Linux/linux-$kernel$--.efi_. might be _/efi_, _/boot_ or _/boot/efi_ depending on where the ESP partition is mounted. The is taken from BUILD_ID in _/usr/lib/os-release_ or if it exists _/etc/os-release_ and is left out, if BUILD_ID is non-existent or empty. **--no-uefi**:: Disables UEFI mode. **--no-machineid**:: Affects the default output filename of **--uefi** and will discard the part. **--uefi-stub __**:: Specifies the UEFI stub loader, which will load the attached kernel, initramfs and kernel command line and boots the kernel. The default is _$prefix/lib/systemd/boot/efi/linux.efi.stub_. **--uefi-splash-image __**:: Specifies the UEFI stub loader's splash image. Requires bitmap (**.bmp**) image format. **--kernel-image __**:: Specifies the kernel image, which to include in the UEFI executable. The default is _/lib/modules//vmlinuz_ or _/boot/vmlinuz-_. **--sbat **:: Specifies the SBAT parameters, which to include in the UEFI executable. By default the default SBAT string added is "sbat,1,SBAT Version,sbat,1, https://github.com/rhboot/shim/blob/main/SBAT.md". **--enhanced-cpio**:: Attempt to use the dracut-cpio binary, which optimizes archive creation for copy-on-write filesystems by using the copy_file_range(2) syscall via Rust's io::copy(). When specified, initramfs archives are also padded to ensure optimal data alignment for extent sharing. To retain reflink data deduplication benefits, this should be used alongside the **--no-compress** and **--nostrip** parameters, with initramfs source files, **--tmpdir** staging area and destination all on the same copy-on-write capable filesystem. ENVIRONMENT ----------- _INITRD_COMPRESS_:: sets the default compression program. See **--compress**. _DRACUT_LDCONFIG_:: sets the _ldconfig_ program path and options. Optional. Used for **--sysroot**. + Default: _ldconfig_ _DRACUT_LDD_:: sets the _ldd_ program path and options. Optional. Used for **--sysroot**. + Default: _ldd_ _DRACUT_TESTBIN_:: sets the initially tested binary for detecting library paths. Optional. Used for **--sysroot**. In the cross-compiled sysroot, the default value (_/bin/sh_) is unusable, as it is an absolute symlink and points outside the sysroot directory. + Default: _/bin/sh_ _DRACUT_INSTALL_:: overrides path and options for executing _dracut-install_ internally. Optional. Can be used to debug _dracut-install_ while running the main dracut script. + Default: _dracut-install_ + Example: DRACUT_INSTALL="valgrind dracut-install" _DRACUT_COMPRESS_BZIP2_:: _DRACUT_COMPRESS_LBZIP2_:: _DRACUT_COMPRESS_LZMA_:: _DRACUT_COMPRESS_XZ_:: _DRACUT_COMPRESS_GZIP_:: _DRACUT_COMPRESS_PIGZ_:: _DRACUT_COMPRESS_LZOP_:: _DRACUT_COMPRESS_ZSTD_:: _DRACUT_COMPRESS_LZ4_:: _DRACUT_COMPRESS_CAT_:: overrides for compression utilities to support using them from non-standard paths. + Default values are the default compression utility names to be found in **PATH**. _DRACUT_ARCH_:: overrides the value of **uname -m**. Used for **--sysroot**. + Default: _empty_ (the value of **uname -m** on the host system) _SYSTEMD_VERSION_:: overrides systemd version. Used for **--sysroot**. _SYSTEMCTL_:: overrides the systemctl binary. Used for **--sysroot**. _NM_VERSION_:: overrides the NetworkManager version. Used for **--sysroot**. _DRACUT_INSTALL_PATH_:: overrides **PATH** environment for **dracut-install** to look for binaries relative to **--sysroot**. In a cross-compiled environment (e.g. Yocto), PATH points to natively built binaries that are not in the host's /bin, /usr/bin, etc. **dracut-install** still needs plain /bin and /usr/bin that are relative to the cross-compiled sysroot. + Default: _PATH_ _DRACUT_INSTALL_LOG_TARGET_:: overrides **DRACUT_LOG_TARGET** for **dracut-install**. It allows running **dracut-install* to run with different log target that **dracut** runs with. + Default: _DRACUT_LOG_TARGET_ _DRACUT_INSTALL_LOG_LEVEL_:: overrides **DRACUT_LOG_LEVEL** for **dracut-install**. It allows running **dracut-install* to run with different log level that **dracut** runs with. + Default: _DRACUT_LOG_LEVEL_ 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:$$https://github.com/dracut-ng/dracut-ng$$[https://github.com/dracut-ng/dracut-ng] AUTHORS ------- Harald Hoyer Victor Lowther Amadeusz Żołnowski Hannes Reinecke Daniel Molkentin Will Woods Philippe Seewer Warren Togami SEE ALSO -------- *dracut.cmdline*(7) *dracut.conf*(5) *lsinitrd*(1)