From 888d53f270a1a163460d764c886c23f2f276c035 Mon Sep 17 00:00:00 2001 From: Harald Hoyer Date: Wed, 14 Mar 2012 13:58:26 +0100 Subject: [PATCH] replace xml documentation with asciidoc --- Makefile | 7 +- dracut-catimages.8.asc | 59 +++ dracut-catimages.8.xml | 116 ----- dracut.8.asc | 378 ++++++++++++++ dracut.8.xml | 684 ------------------------- dracut.asc | 1026 +++++++++++++++++++++++++++++++++++++ dracut.cmdline.7.asc | 603 ++++++++++++++++++++++ dracut.cmdline.7.xml | 1324 ------------------------------------------------ dracut.conf.5.asc | 135 +++++ dracut.conf.5.xml | 297 ----------- dracut.xml | 729 -------------------------- 11 files changed, 2207 insertions(+), 3151 deletions(-) create mode 100644 dracut-catimages.8.asc delete mode 100644 dracut-catimages.8.xml create mode 100644 dracut.8.asc delete mode 100644 dracut.8.xml create mode 100644 dracut.asc create mode 100644 dracut.cmdline.7.asc delete mode 100644 dracut.cmdline.7.xml create mode 100644 dracut.conf.5.asc delete mode 100644 dracut.conf.5.xml delete mode 100644 dracut.xml diff --git a/Makefile b/Makefile index d79b2b0..bd27d06 100644 --- a/Makefile +++ b/Makefile @@ -19,11 +19,16 @@ all: syncheck %: %.xml xsltproc -o $@ -nonet http://docbook.sourceforge.net/release/xsl/current/manpages/docbook.xsl $< -dracut.html: dracut.xml $(manpages) +%.xml: %.asc + asciidoc -d manpage -b docbook -o $@ $< + +dracut.html: dracut.asc $(manpages) + asciidoc -a numbered -d book -b docbook -o dracut.xml dracut.asc xsltproc -o dracut.html --xinclude -nonet \ --stringparam draft.mode yes \ --stringparam html.stylesheet http://docs.redhat.com/docs/en-US/Common_Content/css/default.css \ http://docbook.sourceforge.net/release/xsl/current/xhtml/docbook.xsl dracut.xml + rm dracut.xml install: doc mkdir -p $(DESTDIR)$(pkglibdir) diff --git a/dracut-catimages.8.asc b/dracut-catimages.8.asc new file mode 100644 index 0000000..57f422c --- /dev/null +++ b/dracut-catimages.8.asc @@ -0,0 +1,59 @@ +DRACUT-CATIMAGES(8) +=================== +:doctype: manpage +:man source: dracut +:man manual: dracut + +NAME +---- +dracut-catimages - creates initial ramdisk image by concatenating images + +SYNOPSIS +-------- +**dracut-catimages** [_OPTION_...] __ [__...] + +DESCRIPTION +----------- +dracut-catimages creates an initial ramdisk image by concatenating several +images from the command line and /boot/dracut/*.img + +OPTIONS +------- +**-f, --force**:: + overwrite existing initramfs file. + +**-i, --imagedir**:: + Directory with additional images to add (default: /boot/dracut/) + +**-o, --overlaydir**:: + Overlay directory, which contains additional files that will be used to + create an additional image + +**--nooverlay**:: Do not use the overlay directory + +**--noimagedir**:: Do not use the additional image directory + +**-h, --help**:: display help text and exit. + +**--debug**:: output debug information of the build process + +**-v, --verbose**:: verbose output during the build process + +FILES +----- +_/boot/dracut/*.img_:: + images to work with + +AUTHORS +------- +Harald Hoyer + +AVAILABILITY +------------ +The dracut-catimages command is part of the dracut package and is available from +link:$$https://dracut.wiki.kernel.org$$[https://dracut.wiki.kernel.org] + +SEE ALSO +-------- +*dracut*(8) + diff --git a/dracut-catimages.8.xml b/dracut-catimages.8.xml deleted file mode 100644 index ae8a3ab..0000000 --- a/dracut-catimages.8.xml +++ /dev/null @@ -1,116 +0,0 @@ - - - - - -DRACUT-CATIMAGES -8 -June 2009 -Linux - - -dracut-catimages -creates initial ramdisk image by concatenating images - - - - - dracut-catimages OPTION - <initramfs - base - image> - <image> - - - - - -DESCRIPTION -dracut-catimages -creates an initial ramdisk image by concatenating several images from the command -line and /boot/dracut/*.img - - - -OPTIONS - - - , - -overwrite existing initramfs file. - - - - , - -Directory with additional images to add (default: /boot/dracut/) - - - - , - -Overlay directory, which contains additional files that will be used to create an additional image - - - - - -Do not use the overlay directory - - - - - -Do not use the additional image directory - - - - , - -display help text and exit. - - - - - -output debug information of the build process - - - - , - -verbose output during the build process - - - - - - -FILES - - - /boot/dracut/*.img - - - - - - - -AUTHORS - -Harald Hoyer <harald@redhat.com> - - - -AVAILABILITY -The dracut-catimages command is part of the dracut package and is available from -https://dracut.wiki.kernel.org - - - -SEE ALSO -dracut8 - - - diff --git a/dracut.8.asc b/dracut.8.asc new file mode 100644 index 0000000..6ca7347 --- /dev/null +++ b/dracut.8.asc @@ -0,0 +1,378 @@ +DRACUT(8) +========= +:doctype: manpage +:man source: dracut +:man manual: dracut + +NAME +---- +dracut - low-level tool for generating an initramfs image + +SYNOPSIS +-------- +*dracut* ['OPTION...'] [ [__]] + +DESCRIPTION +----------- +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) + +OPTIONS +------- +**-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-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 + +**--prefix** __:: + prefix initramfs files with the specified directory + +**--noprefix**:: + do not prefix initramfs files (default) + +**--ctty**:: + if possible, try to spawn an emergency shell on a terminal with job control + +**-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_ + +**--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. ++ +[WARNING] +==== +If chrooted to another root other than the real root device, use "--fstab" and provide a valid _/etc/fstab_. +==== + +**--fstab**:: + Use _/etc/fstab_ instead of _/proc/self/mountinfo_. + +**--add_fstab** __ :: + Add entries of __ to the initramfs /etc/fstab. + +**--mount** "__ __ __ __":: + Add entries of __ to the initramfs /etc/fstab. + +**-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. + +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 + +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. + +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*:: + Project Leader and Developer + +*Victor Lowther*:: + Developer + +*Philippe Seewer*:: + Developer + +*Warren Togami*:: + Developer + +*Amadeusz Żołnowski*:: + Developer + +*Jeremy Katz*:: + Developer + +*David Dillow*:: + Developer + +*Will Woods*:: + Developer + +SEE ALSO +-------- +*dracut.cmdline*(7) *dracut.conf*(5) diff --git a/dracut.8.xml b/dracut.8.xml deleted file mode 100644 index de1a0bf..0000000 --- a/dracut.8.xml +++ /dev/null @@ -1,684 +0,0 @@ - - - - - - dracut - dracut - - - Project Leader, Developer - Harald - Hoyer - harald@redhat.com - - - Developer - Victor - Lowther - victor.lowther@gmail.com - - - Developer - Philippe - Seewer - philippe.seewer@bfh.ch - - - Developer - Warren - Togami - - - Developer - Amadeusz - Żołnowski - aidecoe@aidecoe.name - - - Developer - Jeremy - Katz - - - Developer - David - Dillow - dave@thedillows.org - - - - - dracut - 8 - - - - dracut - create initial ramdisk images for preloading modules - - - - dracut - - OPTION - - - <image> - - <kernel-version> - - - - - - - Description - 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. - -For a complete list of kernel command line options see - - dracut.cmdline - 7 - - - - Options - - - - - - - - - - overwrite existing initramfs file. - - - - - - - - - - - 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. - - If [LIST] has multiple arguments, then you have to put these in quotes. - For example: - # dracut --modules "module1 module2" ... - - - - - - - - - - - - omit a space-separated list of dracut modules. This parameter can be specified multiple times. - - If [LIST] has multiple arguments, then you have to put these in quotes. - For example: - # dracut --omit "module1 module2" ... - - - - - - - - - - - - add a space-separated list of dracut modules to the default set of modules. This parameter can be specified multiple times. - - If [LIST] has multiple arguments, then you have to put these in quotes. - For example: - # dracut --add "module1 module2" ... - - - - - - - - - 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. - - If [LIST] has multiple arguments, then you have to put these in quotes. - For example: - # dracut --force-add "module1 module2" ... - - - - - - - - - - - - - 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. - - If [LIST] has multiple arguments, then you have to put these in quotes. - For example: - # dracut --drivers "kmodule1 kmodule2" ... - - - - - - - - - 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. - - If [LIST] has multiple arguments, then you have to put these in quotes. - For example: - # dracut --add-drivers "kmodule1 kmodule2" ... - - - - - - - - - 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. - - If [LIST] has multiple arguments, then you have to put these in quotes. - For example: - # dracut --omit-drivers "kmodule1 kmodule2" ... - - - - - - - - - specify a space-separated list of kernel filesystem modules to exclusively -include in the generic initramfs. This parameter can be specified multiple times. - - If [LIST] has multiple arguments, then you have to put these in quotes. - For example: - # dracut --filesystems "filesystem1 filesystem2" ... - - - - - - - - - - - - specify the directory, where to look for kernel modules - - - - - - - - specify additional directories, where to look for firmwares. This parameter can be specified multiple times. - - - - - - - - only install kernel drivers and firmware files - - - - - - - - do not install kernel drivers and firmware files - - - - - - - - include local /etc/mdadm.conf - - - - - - - - do not include local /etc/mdadm.conf - - - - - - - - include local /etc/lvm/lvm.conf - - - - - - - - do not include local /etc/lvm/lvm.conf - - - - - - - - add a space-separated list of fsck tools, in addition to - dracut.conf's specification; the - installation is opportunistic (non-existing tools are ignored) - - - If [LIST] has multiple arguments, then you have to put these in quotes. - For example: - # dracut --fscks "fsck.foo barfsck" ... - - - - - - - - - inhibit installation of any fsck tools - - - - - - - - strip binaries in the initramfs (default) - - - - - - - - do not strip binaries in the initramfs - - - - - - - - prefix initramfs files with the specified directory - - - - - - - - do not prefix initramfs files (default) - - - - - - - - if possible, try to spawn an emergency shell on a terminal - with job control - - - - - - - - - - - display help text and exit. - - - - - - - - output debug information of the build process - - - - - - - - - - - increase verbosity level (default is info(4)) - - - - - - - - - - - decrease verbosity level (default is info(4)) - - - - - - - - - - - specify configuration file to use. -Default: -/etc/dracut.conf - - - - - - - - specify configuration directory to use. -Default: -/etc/dracut.conf.d - - - - - - - - ssh key file used with ssh-client module. - - - - - - - - - - - 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. - - - - - - - - - - - Host-Only mode: Install only what is needed for booting -the local host instead of a generic host. - - If chrooted to another root other than the real root device, use "--fstab" and provide a valid /etc/fstab. - - - - - - - - - Use /etc/fstab instead of /proc/self/mountinfo. - - - - - - - - Add entries of <filename> to the initramfs /etc/fstab. - - - - - - - - Add entries of <filename> to the initramfs /etc/fstab. - - - - - - - - - - - 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. - - - - - - - - - - - install the space separated list of files into the initramfs. - - If [LIST] has multiple arguments, then you have to put these in quotes. - For example: - # dracut --install "/bin/foo /sbin/bar" ... - - - - - - - - - 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" - - - - - - - - Compress the generated initramfs using bzip2. - - Make sure your kernel has bzip2 decompression support compiled in, otherwise you will not be able to boot. Equivalent to "--compress=bzip2" - - - - - - - - - Compress the generated initramfs using lzma. - - Make sure your kernel has lzma decompression support compiled in, otherwise you will not be able to boot. Equivalent to "--compress=lzma -9" - - - - - - - - - Compress the generated initramfs using xz. - - 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 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. - - - - - - - - Do not compress the generated initramfs. This will override any other compression options. - - - - - - - - List all available dracut modules. - - - - - - - - - - - Print included module's name to standard output during build. - - - - - - - - Keep the initramfs temporary directory for debugging purposes. - - - - - - - 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.conf - 5 - - - - - - /etc/dracut.conf.d/*.conf - - - see - dracut.conf - 5 - - - - - - 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. - - - - - - - Availability - The dracut command is part of the dracut package and is available from -https://dracut.wiki.kernel.org - - - See Also - - - dracut.cmdline - 7 - - - dracut.conf - 5 - - - - diff --git a/dracut.asc b/dracut.asc new file mode 100644 index 0000000..a4bf726 --- /dev/null +++ b/dracut.asc @@ -0,0 +1,1026 @@ +dracut +====== +Harald Hoyer +v2.0, March 2011 + +:language: bash + += Introduction +This section is a modified version of +http://en.wikipedia.org/wiki/Initrd which is licensed under the +Creative Commons Attribution/Share-Alike License. + +== Definition +An _initial ramdisk_ is a temporary file system used in the boot process of the +Linux kernel. _initrd_ and _initramfs_ refer to slightly different schemes for +loading this file system into memory. Both are commonly used to make +preparations before the real root file system can be mounted. + +== Rationale +Many Linux distributions ship a single, generic kernel image that is intended to +boot as wide a variety of hardware as possible. The device drivers for this +generic kernel image are included as loadable modules, as it is not possible to +statically compile them all into the one kernel without making it too large to +boot from computers with limited memory or from lower-capacity media like floppy +disks. + +This then raises the problem of detecting and loading the modules necessary to +mount the root file system at boot time (or, for that matter, deducing where or +what the root file system is). + +To further complicate matters, the root file system may be on a software RAID +volume, LVM, NFS (on diskless workstations), or on an encrypted partition. All +of these require special preparations to mount. + +Another complication is kernel support for hibernation, which suspends the +computer to disk by dumping an image of the entire system to a swap partition or +a regular file, then powering off. On next boot, this image has to be made +accessible before it can be loaded back into memory. + +To avoid having to hardcode handling for so many special cases into the kernel, +an initial boot stage with a temporary root file system +—now dubbed early user space— is used. This root file system would contain +user-space helpers that would do the hardware detection, module loading and +device discovery necessary to get the real root file system mounted. + +== Implementation +An image of this initial root file system (along with the kernel image) must be +stored somewhere accessible by the Linux bootloader or the boot firmware of the +computer. This can be: + +* The root file system itself +* A boot image on an optical disc +* A small ext2/ext3 or FAT-formatted partition on a local disk + (a _boot partition_) +* A TFTP server (on systems that can boot from Ethernet) + +The bootloader will load the kernel and initial root file system image into +memory and then start the kernel, passing in the memory address of the image. + +Depending on which algorithms were compiled statically into it, the kernel can +currently unpack initrd/initramfs images compressed with gzip, bzip2 and LZMA. + +== Mount preparations +dracut can generate a customized initrams image which contains only whatever is +necessary to boot some particular computer, such as ATA, SCSI and filesystem +kernel modules (host-only mode). + +dracut can also generate a more generic initramfs image (default mode). + +dracut's initramfs starts only with the device name of the root file system (or +its UUID) and must discover everything else at boot time. A complex cascade of +tasks must be performed to get the root file system mounted: + +* Any hardware drivers that the boot process depends on must be loaded. All +kernel modules for common storage devices are packed onto the initramfs and then +udev pulls in modules matching the computer's detected hardware. + +* On systems which display a boot rd.splash screen, the video hardware must be +initialized and a user-space helper started to paint animations onto the display +in lockstep with the boot process. + +* If the root file system is on NFS, dracut does then: +** Bring up the primary network interface. +** Invoke a DHCP client, with which it can obtain a DHCP lease. +** Extract the name of the NFS share and the address of the NFS server from the +lease. +** Mount the NFS share. + +* If the root file system appears to be on a software RAID device, there is no +way of knowing which devices the RAID volume spans; the standard MD utilities +must be invoked to scan all available block devices with a raid signature and +bring the required ones online. + +* If the root file system appears to be on a logical volume, the LVM utilities +must be invoked to scan for and activate the volume group containing it. + +* If the root file system is on an encrypted block device: +** Invoke a helper script to prompt the user to type in a passphrase and/or +insert a hardware token (such as a smart card or a USB security dongle). + +* Create a decryption target with the device mapper. + +dracut uses udev, an event-driven hotplug agent, which invokes helper programs +as hardware devices, disk partitions and storage volumes matching certain rules +come online. This allows discovery to run in parallel, and to progressively +cascade into arbitrary nestings of LVM, RAID or encryption to get at the root +file system. + +When the root file system finally becomes visible: + +* Any maintenance tasks which cannot run on a mounted root file system +are done. +* The root file system is mounted read-only. +* Any processes which must continue running (such as the rd.splash screen helper +and its command FIFO) are hoisted into the newly-mounted root file system. + +The final root file system cannot simply be mounted over /, since that would +make the scripts and tools on the initial root file system inaccessible for any +final cleanup tasks. On an initramfs, the initial root file system cannot be +rotated away. Instead, it is simply emptied and the final root file system +mounted over the top. + += User Manual + +== Creating an initramfs Image +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 '' 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. + +=== Inspecting the Contents +To see the contents of the image created by dracut, you can use the lsinitrd tool. +---- +# lsinitrd /boot/initramfs-$(uname -r).img | less +---- + +To display the contents of a file in the initramfs also use the lsinitrd tool: +---- +# lsinitrd /boot/initramfs-$(uname -r).img /etc/ld.so.conf +include ld.so.conf.d/*.conf +---- + +=== Adding dracut Modules +Some dracut modules are turned off by default and have to be activated manually. +You can do this by adding the dracut modules to the configuration file +_/etc/dracut.conf_ or _/etc/dracut.conf.d/myconf.conf_. See <>. +You can also add dracut modules on the command line +by using the -a or --add option: +---- +# dracut --add bootchart initramfs-bootchart.img +---- + +To see a list of available dracut modules, use the --list-modules option: +---- +# dracut --list-modules +---- + +or, if you have a dracut version earlier than +008+, issue the command: +---- +# for mod in /usr/lib/dracut/modules.d/*; do echo ${mod##*/??}; done +---- + +=== Omitting dracut Modules +Sometimes you don't want a dracut module to be included for reasons of speed, +size or functionality. To do this, either specify the omit_dracutmodules +variable in the _dracut.conf_ or _/etc/dracut.conf.d/myconf.conf_ configuration +file (see <>), or use the -o or --omit option +on the command line: +---- +# dracut -o "multipath lvm" no-multipath-lvm.img +---- + +=== Adding Kernel Modules +If you need a special kernel module in the initramfs, which is not +automatically picked up by dracut, you have the use the --add-drivers option +on the command line or the drivers vaiable in the _/etc/dracut.conf_ +or _/etc/dracut.conf.d/myconf.conf_ configuration file (see <>): +---- +# dracut --add-drivers mymod initramfs-with-mymod.img +---- + +== Boot parameters +The generated initramfs.img file normally does not contain any system +configuration files (except for some special exceptions), so the configuration +has to be done on the kernel command line. With this flexibility, you can easily +boot from a changed root partition, without the need to recompile the initramfs +image. So, you could completly change your root partition (move it inside a md +raid with encryption and LVM on top), as long as you specify the correct +filesystem LABEL or UUID on the kernel command line for your root device, dracut +will find it and boot from it. + +The kernel command line usually can be configured in _/boot/grub/grub.conf_, if +grub is your bootloader and it also can be edited in the real boot process in +the grub menu. + +The kernel command line can also be provided by the dhcp server with the +root-path option. See <>. + +For a full reference of all kernel command line parameters, see <>. + +=== Specifying the root Device +This is the only option dracut really needs to boot from your root partition. +Because your root partition can live in various environments, there are a lot of +formats for the root= option. The most basic one is root=_++++_: +---- +root=/dev/sda2 +---- + +Because device node names can change, dependent on the drive ordering, you are +encouraged to use the filesystem identifier (UUID) or filesystem label (LABEL) +to specify your root partition: +---- +root=UUID=19e9dda3-5a38-484d-a9b0-fa6b067d0331 +---- + +or + +---- +root=LABEL=myrootpartitionlabel +---- + +To see all UUIDs or LABELs on your system, do: +---- +# ls -l /dev/disk/by-uuid +---- + +or + +---- +# ls -l /dev/disk/by-label +---- + +If your root partition is on the network see <>. + +=== Keyboard Settings +If you have to input passwords for encrypted disk volumes, you might want to set +the keyboard layout and specify a display font. + +A typical german kernel command would contain: +---- +vconsole.font=latarcyrheb-sun16 vconsole.keymap=de-latin1-nodeadkeys locale.LANG=de_DE.UTF-8 +---- + +Setting these options can override the setting stored on your system, if you use +a modern init system, like systemd. + +For dracut versions prior to version +008+ the line would look like: +---- +LANG=de_DE.UTF-8 SYSFONT=latarcyrheb-sun16 KEYBOARDTYPE=pc KEYTABLE=de-latin1-nodeadkeys +---- + +=== Blacklisting Kernel Modules +Sometimes it is required to prevent the automatic kernel module loading of a +specific kernel module. To do this, just add rd.blacklist=_++++_, with _++++_ not containing the _.ko_ +suffix, to the kernel command line. For example: +---- +rd.driver.blacklist=mptsas rd.driver.blacklist=nouveau +---- + +The option can be specified multiple times on the kernel command line. + +=== Speeding up the Boot Process +If you want to speed up the boot process, you can specify as much information +for dracut on the kernel command as possible. For example, you can tell dracut, +that you root partition is not on a LVM volume or not on a raid partition, or +that it lives inside a specific crypto LUKS encrypted volume. By default, dracut +searches everywhere. A typical dracut kernel command line for a plain primary or +logical partition would contain: +---- +rd.luks=0 rd.lvm=0 rd.md=0 rd.dm=0 +---- + +On systems with dracut version prior to +008+ the line would look like: +---- +rd_NO_LUKS rd_NO_LVM rd_NO_MD rd_NO_DM +---- + +This turns off every automatic assembly of LVM, MD raids, DM raids and crypto LUKS. + +Of course, you could also omit the dracut modules in the initramfs creation +process, but then you would lose the posibility to turn it on on demand. + + +[[Injecting]] +=== Injecting custom Files +To add your own files to the initramfs image, you have several possibilities. + +The --include option let you specify a source path and a target path. For example +---- +# dracut --include cmdline-preset /etc/cmdline initramfs-cmdline-pre.img +---- +will create an initramfs image, where the file cmdline-preset will be copied +inside the initramfs to _/etc/cmdline_. --include can only be specified once. + + +---- +# mkdir rd.live.overlay +# mkdir rd.live.overlay/etc +# mkdir rd.live.overlay/etc/conf.d +# echo "ip=auto" >> rd.live.overlay/etc/cmdline +# echo export TESTVAR=testtest >> rd.live.overlay/etc/conf.d/testvar.conf +# echo export TESTVAR=testtest >> rd.live.overlay/etc/conf.d/testvar.conf +# tree rd.live.overlay/ +rd.live.overlay/ +└── etc + ├── cmdline + └── conf.d + └── testvar.conf +# dracut --include rd.live.overlay / initramfs-rd.live.overlay.img +---- + +This will put the contents of the rd.live.overlay directory into the root of the +initramfs image. + +The --install option let you specify several files, which will get installed in +the initramfs image at the same location, as they are present on initramfs +creation time. + + +---- +# dracut --install 'strace fsck.ext3 ssh' initramfs-dbg.img +---- + +This will create an initramfs with the strace, fsck.ext3 and ssh executables, +together with the libraries needed to start those. The --install option can be +specified multiple times. + + +[[NetworkBoot]] +== Network Boot + +If your root partition is on a network drive, you have to have the network +dracut modules installed to create a network aware initramfs image. + +On a Red Hat Enterprise Linux or Fedora system, this means, you have to install +the _dracut-network_ rpm package: + + +---- +# yum install dracut-network +---- + +The resulting initramfs image can be served by a boot manager residing on your +local hard drive or it can be served by a PXE/TFTP server. + +How to setup your PXE/TFTP server can be found in the +http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/Storage_Administration_Guide/[Red +Hat Enterprise Linux Storage Administration Guide]. + +If you specify rd.ip=auto on the kernel command line, then dracut asks a dhcp +server about the ip adress for the machine. The dhcp server can also serve an +additional root-path, which will set the root device for dracut. With this +mechanism, you have static configuration on your client machine and a +centralized boot configuration on your TFTP/DHCP server. If you can't pass a +kernel command line, then you can inject _/etc/cmdline_, with a method described +in <>. + + + + +=== Reducing the Image Size + +To reduce the size of the initramfs, you should create it with by ommitting all +dracut modules, which you know, you don't need to boot the machine. + +You can also specify the exact dracut and kernel modules to produce a very tiny +initramfs image. + +For example for a NFS image, you would do: + + +---- +# dracut -m "nfs network base" initramfs-nfs-only.img +---- + +Then you would boot from this image with your target machine and reduce the size +once more by creating it on the target machine with the --host-only option: + + +---- +# dracut -m "nfs network base" --host-only initramfs-nfs-host-only.img +---- + +This will reduce the size of the initramfs image significantly. + + + +=== NFS Root Device + +FIXME + +=== iSCSI Root Device + +FIXME + +=== FCoE Root Device + +FIXME + +== Troubleshooting + +If the boot process does not succeed, you have several options to debug the +situation. Some of the basic operations are covered here. For more information +you should also visit: +http://fedoraproject.org/wiki/How_to_debug_Dracut_problems + + +[[identifying-your-problem-area]] +=== Identifying your problem area +. Remove ''rhgb'' and ''quiet'' from the kernel command line +. Add ''rd.shell'' to the kernel command line. This will present a shell should +dracut be unable to locate your root device +. Add ''rd.shell rd.debug log_buf_len=1M'' to the kernel command line so that +dracut shell commands are printed as they are executed +. With dracut >= 002-11, you can inspect the rd.debug output with: ++ +---- +# less /run/initramfs/init.log +# dmesg | less +---- + +[[information-to-include-in-your-report]] +=== Information to include in your report + +[[all-bug-reports]] +==== All bug reports +In all cases, the following should be mentioned and attached to your bug report: + +* The exact kernel command-line used. Typically from the bootloader +configuration file (e.g. _/etc/grub.conf_) or from _/proc/cmdline_. +* A copy of your disk partition information from _/etc/fstab_, which might be +obtained booting an old working initramfs or a rescue medium. +* A device listing from device-mapper. This can be obtained by running the +command ++ +---- +# dmsetup ls --tree +---- ++ +* A list of block device attributes including vol_id compatible mode. This can +be obtained by running the commands: ++ +---- +# blkid -p +# blkid -p -o udev +---- +* Turn on dracut debugging (see _the 'debugging dracut' section_), and attach +all relevant information from the boot log. This can be obtained by running the +command ++ +---- +# dmesg|grep dracut +---- ++ +* If you use a dracut configuration file, please include _/etc/dracut.conf_ and +all files in _/etc/dracut.conf.d/*.conf_ + +[[logical-volume-management-related-problems]] +==== Logical Volume Management related problems +As well as the information from <> include the following +information: + +* Include physical volume information by running the command: ++ +---- +# lvm pvdisplay +---- ++ +* Include volume group information by running the command: ++ +---- +# lvm vgdisplay +---- ++ +* Include logical volume information by running the command: ++ +---- +# lvm lvdisplay +---- + +[[software-raid-related-problems]] +==== Software RAID related problems +As well as the information from <>, include the following +information: + +* If using software RAID disk partitions, please include the output of ++ +---- +# cat /proc/mdstat +---- + +[[network-root-device-related-problems]] +==== Network root device related problems +This section details information to include when experiencing problems on a +system whose root device is located on a network attached volume (e.g. iSCSI, +NFS or NBD). As well as the information from <>, include the +following information: + + +* Please include the output of ++ +---- +# /sbin/ifup +# ip addr show +---- + +[[debugging-dracut]] +=== Debugging dracut + + +[[configure-a-serial-console]] +==== Configure a serial console + +Successfully debugging dracut will require some form of console +logging during the system boot. This section documents configuring a +serial console connection to record boot messages. + +. First, enable serial console output for both the kernel and the bootloader. +. Open the file _/etc/grub.conf_ for editing. Below the line ''timeout=5'', add +the following: ++ +---- +serial --unit=0 --speed=9600 +terminal --timeout=5 serial console +---- ++ +. Also in _/etc/grub.conf_, add the following boot arguemnts to the ''kernel'' +line: ++ +---- +console=tty0 console=ttyS0,9600 +---- ++ +. When finished, the _/etc/grub.conf_ file should look similar to the example +below. ++ +---- +default=0 +timeout=5 +serial --unit=0 --speed=9600 +terminal --timeout=5 serial console +title Fedora (2.6.29.5-191.fc11.x86_64) + root (hd0,0) + kernel /vmlinuz-2.6.29.5-191.fc11.x86_64 ro root=/dev/mapper/vg_uc1-lv_root console=tty0 console=ttyS0,9600 + initrd /dracut-2.6.29.5-191.fc11.x86_64.img +---- ++ +. More detailed information on how to configure the kernel for console output +can be found at +http://www.faqs.org/docs/Linux-HOWTO/Remote-Serial-Console-HOWTO.html#CONFIGURE-KERNEL. +. Redirecting non-interactive output ++ +-- +NOTE: You can redirect all non-interactive output to _/dev/kmsg_ and the kernel +will put it out on the console when it reaches the kernel buffer by doing + +---- +# exec >/dev/kmsg 2>&1 >). + +[[accessing-the-root-volume-from-the-dracut-shell]] +==== Accessing the root volume from the dracut shell +From the dracut debug shell, you can manually perform the task of locating and +preparing your root volume for boot. The required steps will depend on how your +root volume is configured. Common scenarios include: + +* A block device (e.g. _/dev/sda7_) +* A LVM logical volume (e.g. _/dev/VolGroup00/LogVol00_) +* An encrypted device (e.g. _/dev/mapper/luks-4d5972ea-901c-4584-bd75-1da802417d83_) +* A network attached device (e.g. netroot=iscsi:@192.168.0.4::3260::iqn.2009-02.org.fedoraproject:for.all) + +The exact method for locating and preparing will vary. However, to continue with +a successful boot, the objective is to locate your root volume and create a +symlink _/dev/root_ which points to the file system. For example, the following +example demonstrates accessing and booting a root volume that is an encrypted +LVM Logical volume. + +. Inspect your partitions using parted ++ +---- +# parted /dev/sda -s p +Model: ATA HTS541060G9AT00 (scsi) +Disk /dev/sda: 60.0GB +Sector size (logical/physical): 512B/512B +Partition Table: msdos +Number Start End Size Type File system Flags +1 32.3kB 10.8GB 107MB primary ext4 boot +2 10.8GB 55.6GB 44.7GB logical lvm +---- ++ +. You recall that your root volume was a LVM logical volume. Scan and activate +any logical volumes. ++ +---- +# lvm vgscan +# lvm vgchange -ay +---- ++ +. You should see any logical volumes now using the command blkid: ++ +---- +# blkid +/dev/sda1: UUID="3de247f3-5de4-4a44-afc5-1fe179750cf7" TYPE="ext4" +/dev/sda2: UUID="Ek4dQw-cOtq-5MJu-OGRF-xz5k-O2l8-wdDj0I" TYPE="LVM2_member" +/dev/mapper/linux-root: UUID="def0269e-424b-4752-acf3-1077bf96ad2c" TYPE="crypto_LUKS" +/dev/mapper/linux-home: UUID="c69127c1-f153-4ea2-b58e-4cbfa9257c5e" TYPE="ext3" +/dev/mapper/linux-swap: UUID="47b4d329-975c-4c08-b218-f9c9bf3635f1" TYPE="swap" +---- ++ +. From the output above, you recall that your root volume exists on an encrypted +block device. Following the guidance disk encryption guidance from the +Installation Guide, you unlock your encrypted root volume. ++ +---- +# UUID=$(cryptsetup luksUUID /dev/mapper/linux-root) +# cryptsetup luksOpen /dev/mapper/linux-root luks-$UUID +Enter passphrase for /dev/mapper/linux-root: +Key slot 0 unlocked. +---- ++ +. Next, make a symbolic link to the unlocked root volume ++ +---- +# ln -s /dev/mapper/luks-$UUID /dev/root +---- ++ +. With the root volume available, you may continue booting the system by exiting +the dracut shell ++ +---- +# exit +---- + +[[additional-dracut-boot-parameters]] +==== Additional dracut boot parameters +For more debugging options, see <> in <>. + += Developer Manual + +== dracut Components + +dracut uses a modular system to build and extend the initramfs image. All +modules are located in _/usr/lib/dracut/modules.d_ or in _/modules.d_. +The most basic dracut module is _99base_. In _99base_ the initial shell script +init is defined, which gets run by the kernel after initramfs loading. Although +you can replace init with your own version of _99base_, this is not encouraged. +Instead you should use, if possible, the hooks of dracut. All hooks, and the +point of time in which they are executed, are described in <>. + +The main script, which creates the initramfs is dracut itsself. It parses all +arguments and sets up the directory, in which everything is installed. It then +executes all check, install, installkernel scripts found in the modules, which +are to be processed. After everything is installed, the install directory is +archived and compressed to the final initramfs image. All helper functions used +by check, install and installkernel are found in in the file _dracut-functions_. +These shell functions are available to all module installer (install, +installkernel) scripts, without the need to source _dracut-functions_. + +A module can check the preconditions for install and installkernel with the +check script. Also dependencies can be expressed with check. If a module passed +check, install and installkernel will be called to install all of the necessary +files for the module. To split between kernel and non-kernel parts of the +installation, all kernel module related parts have to be in installkernel. All +other files found in a module directory are module specific and mostly are hook +scripts and udev rules. + + +[[stages]] +== Boot Process Stages + +The init script in _99base_ is the main script, which prepares the root file +system for usage, runs udev, mounts the real root device, kills the remaining +processes, and switches to the real root device for further booting. dracut +modules can insert custom script at various points, to control the boot process. +These hooks are plain directories containing shell scripts ending with ".sh", +which are sourced by init. +Common used functions are in _dracut-lib.sh_, which can be sourced by any script. + + + +=== Basic Setup + +The first thing init does, is to mount _/proc_ and _/sys_ and manually create +the basic device nodes and symbolic links in _/dev_ needed to execute basic +commands. Then logging is setup according to kernel command line arguments. +_/dev/pts_ and _/dev/shm_ are mounted and the first hook is sourced. + + + +=== Hook: cmdline + +The _cmdline_ hook is a place to insert scripts to parse the kernel command line +and prepare the later actions, like setting up udev rules and configuration +files. + +In this hook the most important environment variable is defined: root. The +second one is rootok, which indicates, that a module claimed to be able to parse +the root defined. So for example, **root=**__iscsi:....__ will be claimed by the +iscsi dracut module, which then sets rootok. + +=== Hook: pre-udev + +This hook is executed right after the cmdline hook and a check if root and +rootok were set. Here modules can take action with the final root, and before +udev has been run. + + + +=== Start Udev + +Now udev is started and the logging for udev is setup. + + + +=== Hook: pre-trigger + +In this hook, you can set udev environment variables with **udevadm control +--property=KEY=_value_** or control the further execution of udev with +udevadm. + + + +=== Trigger Udev + +udev is triggered by calling udevadm trigger, which sends add events for all +devices and subsystems. + + + +=== Main Loop + +Now the main loop of 99base/init begins. Here we loop until udev has settled and +all scripts in _initqueue/finished_ returned true. In this loop there are three +hooks, where scripts can be inserted by calling /sbin/initqueue. + + + +==== Initqueue + +This hook gets executed every time a script is inserted here, regardless of the +udev state. + + + +==== Initqueue settled + +This hooks gets executed every time udev has settled. + + + +==== Initqueue timeout + +This hooks gets executed, when the main loop counter becomes half of the +rd.retry counter. + + + +==== Initqueue finished + +This hook is called after udev has settled and if all scripts herein return 0 +the main loop will be ended. + + + +=== Hook: pre-mount + +Before the root device is mounted all scripts in the hook pre-mount are +executed. In some cases (e.g. NFS) the real root device is already mounted, +though. + + + +=== Hook: mount + +This hook is mainly to mount the real root device. + + + +=== Hook: pre-pivot + +This hook is the last hook and is called before init finally switches root to +the real root device. This is a good place to clean up and kill processes not +needed anymore. + + + +=== Cleanup and switch_root + +Init kills all udev processes, cleans up the environment, sets up the arguments +for the real init process and finally calls switch_root. switch_root removes the +whole filesystem hierarchy of the initramfs, chroot()s to the real root device +and calls /sbin/init with the specified arguments. + +To ensure all files in the initramfs hierarchy can be removed, all processes +still running from the initramfs should not have any open file descriptors left. + + + +== Network Infrastructure + + +FIXME + + +== Writing a Module + +A simple example module is _96insmodpost_, which modprobes a kernel module after +udev has settled and the basic device drivers have been loaded. + +All module installation information is in the file module-setup.sh. + +First we create a check() function, which just exits with 0 indicating that this +module should be included by default. + +check(): + + +---- +return 0 +---- + +The we create the install() function, which installs a cmdline hook with +priority number 20 called _parse-insmodpost.sh_. It also installs the +_insmodpost.sh_ script in _/sbin_. + +install(): + + +---- +inst_hook cmdline 20 "$moddir/parse-insmodpost.sh" +inst_simple "$moddir/insmodpost.sh" /sbin/insmodpost.sh +---- + +The _pase-instmodpost.sh_ parses the kernel command line for a argument +rd.driver.post, blacklists the module from being autoloaded and installs the +hook _insmodpost.sh_ in the _initqueue/settled_. + +_parse-insmodpost.sh_: + + +---- +for p in $(getargs rd.driver.post=); do + echo "blacklist $p" >> /etc/modprobe.d/initramfsblacklist.conf + _do_insmodpost=1 +done + +[ -n "$_do_insmodpost" ] && /sbin/initqueue --settled --unique --onetime /sbin/insmodpost.sh +unset _do_insmodpost + +---- + +_insmodpost.sh_, which is called in the _initqueue/settled_ hook will just +modprobe the kernel modules specified in all rd.driver.post kernel command line +parameters. It runs after udev has settled and is only called once (--onetime). + +_insmodpost.sh_: + + +---- +. /lib/dracut-lib.sh + +for p in $(getargs rd.driver.post=); do + modprobe $p +done + +---- + + + +=== check() + +_check()_ is called by dracut to evaluate the inclusion of a dracut module in +the initramfs. + +$hostonly:: If the $hostonly variable is set, then the module check() function +should be in "hostonly" mode, which means, that the check() should only return +0, if the module is really needed to boot this specific host. + +check() should return with: + +0:: Include the dracut module in the initramfs. + +1:: Do not include the dracut module. The requirements are not fullfilled +(missing tools, etc.) + +255:: Only include the dracut module, if another module requires it or if +explicitly specified in the config file or on the argument list. + + + +=== depends() + +The function depends() should echo all other dracut module names the module +depends on. + + + +=== install() + +dracut_install + +inst + +inst_hook + +inst_rules + + + + + +=== installkernel() + +instmods + + + +=== Creation Functions + + +FIXME + + +=== Initramfs Functions + + +FIXME + + +=== Network Modules + +FIXME + +[[dracut8]] +include::dracut.8.asc[] + +[[dracutconf5]] +include::dracut.conf.5.asc[] + +[[dracutcmdline7]] +include::dracut.cmdline.7.asc[] + +[appendix] +License +------- +This work is licensed under the Creative Commons Attribution/Share-Alike +License. To view a copy of this license, visit +http://creativecommons.org/licenses/by-sa/3.0/ or send a letter to Creative +Commons, 559 Nathan Abbott Way, Stanford, California 94305, USA. + diff --git a/dracut.cmdline.7.asc b/dracut.cmdline.7.asc new file mode 100644 index 0000000..8924b89 --- /dev/null +++ b/dracut.cmdline.7.asc @@ -0,0 +1,603 @@ +DRACUT.CMDLINE(7) +================= +:doctype: manpage +:man source: dracut +:man manual: dracut + +NAME +---- +dracut.cmdline - dracut kernel command line options + +DESCRIPTION +----------- +The root device used by the kernel is specified in the boot configuration +file on the kernel command line, as always. + +The traditional _root=/dev/sda1_ style device specification is allowed, but not +encouraged. The root device should better be identified by LABEL or UUID. If a +label is used, as in _root=LABEL=_ the initramfs will search all +available devices for a filesystem with the appropriate label, and mount that +device as the root filesystem. _root=UUID=_ will mount the partition +with that UUID as the root filesystem. + +In the following all kernel command line parameters, which are processed by +dracut, are described. + +"rd.*" parameters mentioned without "=" are boolean parameters. They can be +turned on/off by setting them to {0|1}. If the assignment with "=" is missing +"=1" is implied. For example _rd.info_ can be turned off with _rd.info=0_ or +turned on with _rd.info=1_ or _rd.info_. The last value in the kernel command +line is the value, which is honored. + +Standard +~~~~~~~~ +**init=**__:: + specify the path to the init programm to be started after the initramfs has + finished + +**root=**__:: + specify the block device to use as the root filesystem. ++ +E.g.: ++ +---- +root=/dev/sda1 +root=/dev/disk/by-path/pci-0000:00:1f.1-scsi-0:0:1:0-part1 +root=/dev/disk/by-label/Root +root=LABEL=Root +root=/dev/disk/by-uuid/3f5ad593-4546-4a94-a374-bcfb68aa11f7 +root=UUID=3f5ad593-4546-4a94-a374-bcfb68aa11f7 +---- + +**rootfstype=**__:: "auto" if not specified, e.g.: ++ +---- +rootfstype=ext3 +---- + +**rootflags=**__:: + specify additional mount options for the root filesystem. If not set, + _/etc/fstab_ of the real root will be parsed for special mount options and + mounted accordingly. + +**rd.fstab=0**:: + do not honor special mount options for the root filesystem found in + _/etc/fstab_ of the real root. + +Misc +~~~~ +**rd.driver.blacklist=**_[,,...]_:: + do not load kernel module . This parameter can be specified + multiple times. + +**rd.driver.pre=**_[,,...]_:: + force loading kernel module . This parameter can be specified + multiple times. + +**rd.driver.post=**_[,,...]_:: + force loading kernel module after all automatic loading modules + have been loaded. This parameter can be specified multiple times. + +**rd.ctty=**__:: + if the dracut image was generated with --ctty option, try to spawn an + emergency shell on the specified terminal; if rd.ctty is specified without a + value or not provided at all, the default is /dev/tty1. The '/dev' prefix + can be omitted. + +[[dracutkerneldebug]] +Debug +~~~~~ +**rd.info**:: + print informational output though "quiet" is set + +**rd.shell**:: + allow dropping to a shell, if root mounting fails + +**rd.debug**:: + set -x for the dracut shell and logs to dmesg, console and + _/run/initramfs/init.log_ + +**rd.break**:: + drop to a shell at the end + +**rd.break=**_{cmdline|pre-udev|pre-trigger|initqueue|pre-mount|mount|pre-pivot}_:: + drop to a shell on defined breakpoint + +**rd.udev.info**:: + set udev to loglevel info + +**rd.udev.debug**:: + set udev to loglevel debug + +I18N +~~~~ +**vconsole.keymap=**__:: + keyboard translation table loaded by loadkeys; taken from keymaps directory; + will be written as KEYMAP to _/etc/vconsole.conf_ in the initramfs, e.g.: ++ +---- +vconsole.keymap=de-latin1-nodeadkeys +---- + +**vconsole.keymap.ext=**__:: + list of extra keymaps to bo loaded (sep. by space); will be written as + EXT_KEYMAP to _/etc/vconsole.conf_ in the initramfs + +**vconsole.unicode**[=_{0|1}_]:: + boolean, indicating UTF-8 mode; will be written as UNICODE to + _/etc/vconsole.conf_ in the initramfs + +**vconsole.font=**__:: + console font; taken from consolefonts directory; will be written as FONT to + _/etc/vconsole.conf_ in the initramfs; e.g.: ++ +---- +vconsole.font=LatArCyrHeb-16 +---- + +**vconsole.font.map=**__:: + see description of '-m' parameter in setfont manual; taken from consoletrans + directory; will be written as FONT_MAP to _/etc/vconsole.conf_ in the + initramfs + +**vconsole.font.unimap=**__:: + see description of '-u' parameter in setfont manual; taken from unimaps + directory; will be written as FONT_UNIMAP to _/etc/vconsole.conf_ in the + initramfs + +**locale.LANG=**__:: + taken from the environment; if no UNICODE is defined we set its value in + basis of LANG value (whether it ends with ".utf8" (or similar) or not); will + be written as LANG to _/etc/locale.conf_ in the initramfs; e.g.: ++ +---- +locale.LANG=pl_PL.utf8 +---- + +**locale.LC_ALL=**__:: + taken from the environment; will be written as LC_ALL to _/etc/locale.conf_ + in the initramfs + +LVM +~~~ +**rd.lvm=0**:: + disable LVM detection + +**rd.lvm.vg=**__:: + only activate the volume groups with the given name. rd.lvm.vg can be + specified multiple times on the kernel command line. + +**rd.lvm.lv=**__:: + only activate the logical volumes with the given name. rd.lvm.lv can be + specified multiple times on the kernel command line. + +**rd.lvm.conf=0**:: + remove any _/etc/lvm/lvm.conf_, which may exist in the initramfs + +crypto LUKS +~~~~~~~~~~~ +**rd.luks=0**:: + disable crypto LUKS detection + +**rd.luks.uuid=**__:: + only activate the LUKS partitions with the given UUID. Any "luks-" of the + LUKS UUID is removed before comparing to __. + The comparisons also matches, if __ is only the beginning of the + LUKS UUID, so you don't have to specify the full UUID. + This parameter can be specified multiple times. + +**rd.luks.crypttab=0**:: + do not check, if LUKS partition is in _/etc/crypttab_ + +crypto LUKS - key on removable device support +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +**rd.luks.key=**_::_:: + _keypath_ is a path to key file to look for. It's REQUIRED. When _keypath_ ends with '.gpg' it's considered to be key encrypted symmetrically with GPG. You will be prompted for password on boot. GPG support comes with 'crypt-gpg' module which needs to be added explicitly. ++ +_keydev_ is a device on which key file resides. It might be kernel name of devices (should start with "/dev/"), UUID (prefixed with "UUID=") or label (prefix with "LABEL="). You don't have to specify full UUID. Just its beginning will suffice, even if its ambiguous. All matching devices will be probed. This parameter is recommended, but not required. If not present, all block devices will be probed, which may significantly increase boot time. ++ +If _luksdev_ is given, the specified key will only be applied for that LUKS device. Possible values are the same as for _keydev_. Unless you have several LUKS devices, you don't have to specify this parameter. The simplest usage is: ++ +---- +rd.luks.key=/foo/bar.key +---- ++ +As you see, you can skip colons in such a case. + +MD RAID +~~~~~~~ +**rd.md=0**:: + disable MD RAID detection + +**rd.md.imsm=0**:: + disable MD RAID for imsm/isw raids, use DM RAID instead + +**rd.md.ddf=0**:: + disable MD RAID for SNIA ddf raids, use DM RAID instead + +**rd.md.conf=0**:: + ignore mdadm.conf included in initramfs + +**rd.md.waitclean=1**:: + wait for any resync, recovery, or reshape activity to finish before continuing + +**rd.md.uuid=**__:: + only activate the raid sets with the given UUID. This parameter can be + specified multiple times. + +DM RAID +~~~~~~~ +**rd.dm=0**:: + disable DM RAID detection + +**rd.dm.uuid=**__:: + only activate the raid sets with the given UUID. This parameter can be + specified multiple times. + +FIPS +~~~~ +**rd.fips**:: + enable FIPS + +**boot=**__:: + specify the device, where /boot is located. e.g. ++ +---- +boot=/dev/sda1 +boot=/dev/disk/by-path/pci-0000:00:1f.1-scsi-0:0:1:0-part1 +boot=UUID= +boot=LABEL=