MKINITCPIO(8)mkinitcpio manual MKINITCPIO(8)NAMEmkinitcpio - Create an initial ramdisk environment
SYNOPSISmkinitcpio [options]
DESCRIPTION
Creates an initial ramdisk environment for booting the linux kernel.
The initial ramdisk is in essence a very small environment (early
userspace) which loads various kernel modules and sets up necessary
things before handing over control to init. This makes it possible to
have, for example, encrypted root filesystems and root filesystems on a
software RAID array. mkinitcpio allows for easy extension with custom
hooks, has autodetection at runtime, and many other features.
OPTIONS-A, --addhooks hooks
Add the additional hooks to the image. These will be processed in
order after all other hooks from the config file. Multiple hooks
should be comma-separated. This option can be specified multiple
times.
-c, --config config
Use config file to generate the ramdisk. Default:
/etc/mkinitcpio.conf
-d, --generatedir directory
Set directory as the location where the initramfs is built. This
might be useful to generate a shutdown ramfs in /run/initramfs.
-g, --generate filename
Generate a CPIO image as filename. Default: no; this means nothing
will be written to the filesystem unless this option is specified.
-H, --hookhelp hookname
Output help for hookname hookname.
-h, --help
Output a short overview of available command-line switches.
-k, --kernel kernelversion
Use kernelversion, instead of the current running kernel. This may
be a path to a kernel image, a specific kernel version or the
special keyword none. In the latter case, no kernel modules are
added to the image.
-L, --listhooks
List all available hooks.
-M, --automods
Display modules found via autodetection. mkinitcpio will
automatically try to determine which kernel modules are needed to
start your computer. This option lists which modules were detected.
-n, --nocolor
Disable color output.
-P, --allpresets
Process all presets contained in /etc/mkinitcpio.d. See the -p
option for more detail about presets.
-p, --preset preset
Build initramfs image(s) according to specified preset. This may be
a file in /etc/mkinitcpio.d (without the .preset extension) or a
full, absolute path to a file. This option may be specified
multiple times to process multiple presets.
-r, --moduleroot root
Specifies the root directory to find modules in, defaulting to /.
-S, --skiphooks hooks
Skip hooks when generating the image. Multiple hooks should be
comma-separated. This option can be specified multiple times.
-s, --save
Saves the build directory for the initial ramdisk. Default: no;
This means the directory will not be retained if this option isn’t
specified. Useful for debugging purposes.
-t, --builddir tmpdir
Use tmpdir as the temporary build directory instead of /tmp.
tmpdir must exist. The TMPDIR environment variable is also honored
to set this location, but the command line option will take
precedence.
-V, --version
Display version information.
-v, --verbose
Verbose output. Outputs more information about what’s happening
during creation of the ramdisk.
-z, --compress compress
Override the compression method with the compress program.
ABOUT PRESETS
A preset is a pre-defined definition on how to create an initial
ramdisk. Instead of specifying the configuration file and which output
file, every time you generate a new initial ramdisk, you define a
preset and use the -p switch to generate an initial ramdisk according
to your preset. Presets are located in /etc/mkinitcpio.d
ABOUT INSTALL HOOKS
Install hooks are bash scripts which are sourced during mkinitcpio
runtime in order to add modules, binaries, and other files to the
image. A variety of functions exist to facilitate this.
add_module modname
Adds the module specified by modname to the image. Dependencies are
derived and added automatically.
add_binary binary [ destination ] [ mode ]
Adds a binary to the image. The argument binary need not be an
absolute path and, if needed, a lookup will be performed. If the
binary is a dynamically linked ELF binary, dependencies will be
automatically added. Optionally, a destination within the initramfs
image as well as a file mode can be specified. By default, the
destintation and mode be taken from the source derived from binary.
add_file path [ destination ] [ mode ]
Adds a file and any needed parent directories to the image.
Optionally, a destination within the initramfs image as well as a
file mode can be specified. By default, the destination and mode
will be taken from the source and mode of the file specified by the
path.
add_dir path
Adds a directory and its parents to the image.
add_full_dir directory
Recursively adds a directory to the image by walking the given path
and calling add_file, add_dir, and add_symlink accordingly. This
function will not follow symlinks, nor will it add the targets of
symlinks.
add_symlink path [ link-target ]
Adds a symlink to the image at the specified path, optionally
pointing to the specified link-target. If the link-target is not
provided, it is assumed that this symlink exists in the real
filesystem, and the target will be read using readlink. There is no
checking done to ensure that the target of the symlink exists, and
symlinks will not be followed recursively.
add_all_modules [ -f filter ] pattern
Adds modules to the image, without regard for the autodetect
whitelist. pattern should be a subdirectory within the kernel tree
describing a subset of modules to be included. Further refinement
can be provided via the -f flag with an extended regular
expression.
add_checked_modules [ -f filter ] pattern
Similar to add_all_modules with the constraint that only modules
matching the whitelist generated by the autodetect hook will be
added to the image. If the autodetect hook is not present in the
image, this function is identical to add_all_modules.
add_runscript
Adds a runtime hook to the image, which is a busybox ash compatible
shell script. The name of the script is guaranteed to match the
name of the hook the script is called from.
ABOUT RUNTIME HOOKS
Runtime hooks added to the image via the add_runscript function from an
install hook are able to provide extra functionality during early
userspace. Specific functions in these files will run at different
times. A hook can define one or more of these. At each hook point,
hooks are run in the order that they are defined in the HOOKS variable,
except for cleanup hooks which are run in reverse.
run_earlyhook
Functions of this name will be run once the API mounts have been
setup and the kernel command line has been parsed. Daemons needed
for early userspace should be started from this hook point.
run_hook
Functions of this name will be run after any early hooks, and after
user defined modules have been installed. This is the most common
hook point, and functionality such as scanning for LVM volumes and
mapping encrypted volumes should be performed here.
run_latehook
Functions of this name will be run after root has been mounted.
This is generally used for further necessary setup in the real
root, such as mounting other system partitions.
run_cleanuphook
Functions of this name are run as late as possible. Any daemons
started from a run_earlyhook function should be shut down here in
preparation for switching to the real root.
EARLY INIT ENVIRONMENTmkinitcpio gives special treatment to certain environment variables
passed on the kernel command line:
break[=<premount|postmount>]
If specified, mkinitcpio will start a shell during early init. The
optional parameter controls when this occurs: when premount or no
parameter are specified, the shell will be launched prior to
mounting root. If postmount is specified, the shell will be
launched after mounting root.
disablehooks=hooklist
This is a comma separated list of hooks which will be skipped
during early init.
earlymodules=modulelist
This is a comma separated list of modules which will be loaded
prior to any others. This is generally not needed, and usually
points to a configuration or kernel problem.
quiet
Causes mkinitcpio to output fewer messages during boot. Errors will
not be suppressed.
ro
Specifies that root should be mounted with readonly permissions.
This is the default behavior.
rw
Specifies that root should be mounted with readwrite permissions.
This is generally only useful if your initramfs uses the fsck hook.
root=rootdevice
This variable describes the root partition which early init will
mount before passing control to the real init. mkinitcpio
understands a variety of formats, the most basic of which is the
path to the block device, either directly such as /dev/sda2, or
using a udev symlink such as /dev/disk/by-label/CorsairF80-root.
Support for identification by LABEL or UUID tags are also
supported, such as, LABEL=CorsairF80-root. As of util-linux 2.22,
PARTUUID and PARTLABEL are also supported. Identification via hex
encoded major/minor device ID is supported for legacy reasons, but
should be avoided as it tends to be fragile.
rootdelay=seconds
Sets the delay, in seconds, that mkinitcpio is willing to wait for
the root device to show up, if it is not available immediately.
This defaults to 5 seconds. If an invalid integer is passed, this
variable will have no effect.
rd.debug
Enables shell debug (xtrace). If rd.log is not also a parameter on
the kernel command line, this parameter implies rd.log=console.
rd.log[=<console|file|kmsg|all>]
Enables logging of early userspace messages. If specified, the
optional parameter describes where this information is logged.
Multiple options can be OR’d together using the pipe (|) character.
Messages are always logged to the console unless the quiet
parameter is passed. If the optional parameter is not specified,
kmsg|console is assumed. If rd.log is not present on the kernel
command line, no logging will take place.
console
Writes output to /dev/console.
file
Writes output to /run/initramfs/init.log.
kmsg
Writes output to the /dev/kmsg device (introduced in Linux
3.5). This option is a no-op if your kernel lacks support for
/dev/kmsg.
all
Writes output to all known log targets.
These are only the variables that the core of mkinitcpio honor.
Additional hooks may look for other environment variables and should be
documented by the help output for the hook.
FILES
/etc/mkinitcpio.conf
Default configuration file for mkinitcpio.
/etc/mkinitcpio.d
Directory containing mkinitcpio presets.
/etc/initcpio/install, /usr/lib/initcpio/install
Search path for build time hooks.
/etc/initcpio/hooks, /usr/lib/initcpio/hooks
Search path for early userspace runtime hooks.
EXAMPLESmkinitcpio
Perform a dry-run. This will generate an initial ramdisk but will
not write anything. Use -g to create the real image.
mkinitcpio-p linux
Create an initial ramdisk based on the linux preset.
mkinitcpio-g /boot/initramfs-linux.img -k /boot/vmlinuz-linux
Create an initial ramdisk for the kernel at /boot/vmlinuz-linux.
The resulting image will be written to /boot/initramfs-linux.img.
SEE ALSO
A more thorough article on configuring mkinitcpio:
http://wiki.archlinux.org/index.php/Mkinitcpio
initrd(4), lsinitcpio(1), mkinitcpio.conf(5), bootparam(7)BUGS
Upon writing this manpage, there were no noticeable bugs present.
Please visit http://bugs.archlinux.org/ for an up to date list.
AUTHORSmkinitcpio is created and maintained by the Arch Linux Developer
community.
COPYRIGHT
Copyright (c) Arch Linux 2006-2012
17 03/08/2014 MKINITCPIO(8)
