dracut.8.asc

   1 DRACUT(8)
   2 =========
   3 :doctype: manpage
   4 :man source:   dracut
   5 :man manual:   dracut
   6
   7 NAME
   8 ----
   9 dracut - low-level tool for generating an initramfs image
  10
  11 SYNOPSIS
  12 --------
  13 *dracut* ['OPTION...'] [<image> [_<kernel version>_]]
  14
  15 DESCRIPTION
  16 -----------
  17
  18 Create an initramfs <image> for the kernel with the version <kernel version>.
  19 If <kernel version> is omitted, then the version of the actual running
  20 kernel is used. If <image> is omitted or empty, then the default location
  21 /boot/initramfs-<kernel version>.img is used.
  22
  23 dracut creates an initial image used by the kernel for preloading the block
  24 device modules (such as IDE, SCSI or RAID) which are needed to access the root
  25 filesystem, mounting the root filesystem and booting into the real system.
  26
  27 At boot time, the kernel unpacks that archive into RAM disk, mounts and uses it
  28 as initial root file system. All finding of the root device happens in this
  29 early userspace.
  30
  31 For a complete list of kernel command line options see *dracut.cmdline*(7).
  32
  33 If you are dropped to an emergency shell, while booting your initramfs,
  34 the file _/run/initramfs/rdsosreport.txt_ is created, which can be safed to a
  35 (to be mounted by hand) partition (usually /boot) or a USB stick.
  36 Additional debugging info can be produced by adding **rd.debug** to the kernel command line.
  37 _/run/initramfs/rdsosreport.txt_ contains all logs and the output of some tools.
  38 It should be attached to any report about dracut problems.
  39
  40 EXAMPLE
  41 -------
  42
  43 To create a initramfs image, the most simple command is:
  44 ----
  45 # dracut
  46 ----
  47
  48 This will generate a general purpose initramfs image, with all possible
  49 functionality resulting of the combination of the installed dracut modules and
  50 system tools. The image is /boot/initramfs-_++<kernel version>++_.img and
  51 contains the kernel modules of the currently active kernel with version
  52 _++<kernel version>++_.
  53
  54 If the initramfs image already exists, dracut will display an error message, and
  55 to overwrite the existing image, you have to use the --force option.
  56 ----
  57 # dracut --force
  58 ----
  59
  60 If you want to specify another filename for the resulting image you would issue
  61 a command like:
  62 ----
  63 # dracut foobar.img
  64 ----
  65
  66 To generate an image for a specific kernel version, the command would be:
  67 ----
  68 # dracut foobar.img 2.6.40-1.rc5.f20
  69 ----
  70
  71 A shortcut to generate the image at the default location for a specific kernel
  72 version is:
  73 ----
  74 # dracut --kver 2.6.40-1.rc5.f20
  75 ----
  76
  77 If you want to create lighter, smaller initramfs images, you may want to specify
  78 the --hostonly or -H option. Using this option, the resulting image will
  79 contain only those dracut modules, kernel modules and filesystems, which are
  80 needed to boot this specific machine. This has the drawback, that you can't put
  81 the disk on another controller or machine, and that you can't switch to another
  82 root filesystem, without recreating the initramfs image. The usage of the
  83 --hostonly option is only for experts and you will have to keep the broken
  84 pieces. At least keep a copy of a general purpose image (and corresponding
  85 kernel) as a fallback to rescue your system.
  86
  87
  88 OPTIONS
  89 -------
  90 **--kver** _<kernel version>_::
  91     set the kernel version. This enables to specify the kernel version, without
  92     specifying the location of the initramfs image. For example:
  93 ----
  94 # dracut --kver 3.5.0-0.rc7.git1.2.fc18.x86_64
  95 ----
  96
  97 **-f, --force**::
  98     overwrite existing initramfs file.
  99
 100 **-m, --modules** _<list of dracut modules>_::
 101     specify a space-separated list of dracut modules to call when building the
 102     initramfs. Modules are located in _/usr/lib/dracut/modules.d_. This
 103     parameter can be specified multiple times.
 104 +
 105 [NOTE]
 106 ===============================
 107 If [LIST] has multiple arguments, then you have to put these in quotes. For
 108 example:
 109 ----
 110 # dracut --modules "module1 module2"  ...
 111 ----
 112 ===============================
 113
 114 **-o, --omit** _<list of dracut modules>_::
 115     omit a space-separated list of dracut modules. This parameter can be
 116     specified multiple times.
 117 +
 118 [NOTE]
 119 ===============================
 120 If [LIST] has multiple arguments, then you have to put these in quotes. For
 121 example:
 122 ----
 123 # dracut --omit "module1 module2"  ...
 124 ----
 125 ===============================
 126
 127 **-a, --add** _<list of dracut modules>_::
 128     add a space-separated list of dracut modules to the default set of modules.
 129     This parameter can be specified multiple times.
 130 +
 131 [NOTE]
 132 ===============================
 133 If [LIST] has multiple arguments, then you have to put these in quotes. For
 134 example:
 135 ----
 136 # dracut --add "module1 module2"  ...
 137 ----
 138 ===============================
 139
 140 **--force-add** _<list of dracut modules>_::
 141     force to add a space-separated list of dracut modules to the default set of
 142     modules, when -H is specified. This parameter can be specified multiple
 143     times.
 144 +
 145 [NOTE]
 146 ===============================
 147 If [LIST] has multiple arguments, then you have to put these in quotes. For
 148 example:
 149 ----
 150 # dracut --force-add "module1 module2"  ...
 151 ----
 152 ===============================
 153
 154 **-d, --drivers** _<list of kernel modules>_::
 155     specify a space-separated list of kernel modules to exclusively include
 156     in the initramfs. The kernel modules have to be specified without the ".ko"
 157     suffix. This parameter can be specified multiple times.
 158 +
 159 [NOTE]
 160 ===============================
 161 If [LIST] has multiple arguments, then you have to put these in quotes. For
 162 example:
 163 ----
 164 # dracut --drivers "kmodule1 kmodule2"  ...
 165 ----
 166 ===============================
 167
 168 **--add-drivers** _<list of kernel modules>_::
 169     specify a space-separated list of kernel modules to add to the initramfs.
 170     The kernel modules have to be specified without the ".ko" suffix. This
 171     parameter can be specified multiple times.
 172 +
 173 [NOTE]
 174 ===============================
 175 If [LIST] has multiple arguments, then you have to put these in quotes. For
 176 example:
 177 ----
 178 # dracut --add-drivers "kmodule1 kmodule2"  ...
 179 ----
 180 ===============================
 181
 182 **--omit-drivers** _<list of kernel modules>_::
 183     specify a space-separated list of kernel modules not to add to the
 184     initramfs.
 185     The kernel modules have to be specified without the ".ko" suffix. This
 186     parameter can be specified multiple times.
 187 +
 188 [NOTE]
 189 ===============================
 190 If [LIST] has multiple arguments, then you have to put these in quotes. For
 191 example:
 192 ----
 193 # dracut --omit-drivers "kmodule1 kmodule2"  ...
 194 ----
 195 ===============================
 196
 197 **--filesystems** _<list of filesystems>_::
 198     specify a space-separated list of kernel filesystem modules to exclusively
 199     include in the generic initramfs. This parameter can be specified multiple
 200     times.
 201 +
 202 [NOTE]
 203 ===============================
 204 If [LIST] has multiple arguments, then you have to put these in quotes. For
 205 example:
 206 ----
 207 # dracut --filesystems "filesystem1 filesystem2"  ...
 208 ----
 209 ===============================
 210
 211 **-k, --kmoddir** _<kernel directory>_::
 212     specify the directory, where to look for kernel modules
 213
 214 **--fwdir** _<dir>[:<dir>...]++_::
 215     specify additional directories, where to look for firmwares. This parameter
 216     can be specified multiple times.
 217
 218 **--kernel-cmdline <parameters>**::
 219     specify default kernel command line parameters
 220
 221
 222 **--kernel-only**::
 223     only install kernel drivers and firmware files
 224
 225 **--no-kernel**::
 226     do not install kernel drivers and firmware files
 227
 228 **--mdadmconf**::
 229     include local _/etc/mdadm.conf_
 230
 231 **--nomdadmconf**::
 232     do not include local _/etc/mdadm.conf_
 233
 234 **--lvmconf**::
 235     include local _/etc/lvm/lvm.conf_
 236
 237 **--nolvmconf**::
 238     do not include local _/etc/lvm/lvm.conf_
 239
 240 **--fscks** [LIST]::
 241     add a space-separated list of fsck tools, in addition to _dracut.conf_'s
 242     specification; the installation is opportunistic (non-existing tools are
 243     ignored)
 244 +
 245 [NOTE]
 246 ===============================
 247 If [LIST] has multiple arguments, then you have to put these in quotes. For
 248 example:
 249 ----
 250 # dracut --fscks "fsck.foo barfsck"  ...
 251 ----
 252 ===============================
 253
 254 **--nofscks**::
 255     inhibit installation of any fsck tools
 256
 257 **--strip**::
 258     strip binaries in the initramfs (default)
 259
 260 **--nostrip**::
 261     do not strip binaries in the initramfs
 262
 263 **--hardlink**::
 264     hardlink files in the initramfs (default)
 265
 266 **--nohardlink**::
 267     do not hardlink files in the initramfs
 268
 269 **--prefix** _<dir>_::
 270     prefix initramfs files with the specified directory
 271
 272 **--noprefix**::
 273     do not prefix initramfs files (default)
 274
 275 **-h, --help**::
 276     display help text and exit.
 277
 278 **--debug**::
 279     output debug information of the build process
 280
 281 **-v, --verbose**::
 282     increase verbosity level (default is info(4))
 283
 284 **-q, --quiet**:: decrease verbosity level (default is info(4))
 285
 286 **-c, --conf** _<dracut configuration file>_::
 287     specify configuration file to use.
 288 +
 289 Default:
 290    _/etc/dracut.conf_
 291
 292 **--confdir** _<configuration directory>_::
 293     specify configuration directory to use.
 294 +
 295 Default:
 296    _/etc/dracut.conf.d_
 297
 298 **--tmpdir** _<temporary directory>_::
 299     specify temporary directory to use.
 300 +
 301 Default:
 302    _/var/tmp_
 303
 304 **--sshkey** _<sshkey file>_:: ssh key file used with ssh-client module.
 305
 306 **-l, --local**::
 307     activates the local mode. dracut will use modules from the current working
 308     directory instead of the system-wide installed modules in
 309     _/usr/lib/dracut/modules.d_.
 310     This is useful when running dracut from a git checkout.
 311
 312 **-H, --hostonly**::
 313     Host-Only mode: Install only what is needed for booting the local host
 314     instead of a generic host and generate host-specific configuration.
 315 +
 316 [WARNING]
 317 ====
 318 If chrooted to another root other than the real root device, use "--fstab" and
 319 provide a valid _/etc/fstab_.
 320 ====
 321
 322 **-N, --no-hostonly**::
 323     Disable Host-Only mode
 324
 325 **--fstab**::
 326     Use _/etc/fstab_ instead of _/proc/self/mountinfo_.
 327
 328 **--add-fstab** _<filename>_ ::
 329     Add entries of _<filename>_ to the initramfs /etc/fstab.
 330
 331 **--mount** "_<device>_ _<mountpoint>_ _<filesystem type>_ _<filesystem options>_"::
 332     Mount _<device>_ on _<mountpoint>_ with _<filesystem type>_ and _<filesystem
 333     options>_ in the initramfs
 334
 335 **--add-device** _<device>_ ::
 336     Bring up _<device>_ in initramfs, _<device>_ should be the device name.
 337     This can be useful in hostonly mode for resume support when your swap is on
 338     LVM or an encrypted partition.
 339     [NB --device can be used for compatibility with earlier releases]
 340
 341 **-i, --include** _<SOURCE>_ _<TARGET>_::
 342     include the files in the SOURCE directory into the
 343     TARGET directory in the final initramfs. If SOURCE is a file, it will be
 344     installed to TARGET in the final initramfs. This parameter can be specified
 345     multiple times.
 346
 347 **-I, --install** _<file list>_::
 348     install the space separated list of files into the initramfs.
 349 +
 350 [NOTE]
 351 ===============================
 352 If [LIST] has multiple arguments, then you have to put these in quotes. For
 353 example:
 354 ----
 355 # dracut --install "/bin/foo /sbin/bar"  ...
 356 ----
 357 ===============================
 358
 359 **--gzip**::
 360     Compress the generated initramfs using gzip. This will be done by default,
 361     unless another compression option or --no-compress is passed. Equivalent to
 362     "--compress=gzip -9"
 363
 364 **--bzip2**::
 365     Compress the generated initramfs using bzip2.
 366 +
 367 [WARNING]
 368 ====
 369 Make sure your kernel has bzip2 decompression support compiled in, otherwise you
 370 will not be able to boot. Equivalent to "--compress=bzip2"
 371 ====
 372
 373 **--lzma**::
 374     Compress the generated initramfs using lzma.
 375 +
 376 [WARNING]
 377 ====
 378 Make sure your kernel has lzma decompression support compiled in, otherwise you
 379 will not be able to boot. Equivalent to "lzma --compress=lzma -9"
 380 ====
 381
 382 **--xz**::
 383     Compress the generated initramfs using xz.
 384 +
 385 [WARNING]
 386 ====
 387 Make sure your kernel has xz decompression support compiled in, otherwise you
 388 will not be able to boot. Equivalent to "lzma --compress=xz --check=crc32 --lzma2=dict=1MiB"
 389 ====
 390
 391 **--compress** _<compressor>_::
 392     Compress the generated initramfs using the passed compression program. If
 393     you pass it just the name of a compression program, it will call that
 394     program with known-working arguments. If you pass a quoted string with
 395     arguments, it will be called with exactly those arguments. Depending on what
 396     you pass, this may result in an initramfs that the kernel cannot decompress.
 397
 398 **--no-compress**::
 399     Do not compress the generated initramfs. This will override any other
 400     compression options.
 401
 402 **--list-modules**::
 403     List all available dracut modules.
 404
 405 **-M, --show-modules**::
 406     Print included module's name to standard output during build.
 407
 408 **--keep**::
 409     Keep the initramfs temporary directory for debugging purposes.
 410
 411 **--printsize**::
 412     Print out the module install size
 413
 414 **--profile**:
 415     Output profile information of the build process
 416
 417 **--ro-mnt**:
 418     Mount / and /usr read-only by default.
 419
 420 **-L, --stdlog** _<level>_::
 421     [0-6] Specify logging level (to standard error)
 422 ----
 423           0 - suppress any messages
 424           1 - only fatal errors
 425           2 - all errors
 426           3 - warnings
 427           4 - info
 428           5 - debug info (here starts lots of output)
 429           6 - trace info (and even more)
 430 ----
 431
 432 **--regenerate-all**::
 433     Regenerate all initramfs images at the default location with the kernel versions found on the system.
 434     Additional parameters are passed through.
 435
 436 FILES
 437 -----
 438 _/var/log/dracut.log_::
 439     logfile of initramfs image creation
 440
 441 _/tmp/dracut.log_::
 442     logfile of initramfs image creation, if _/var/log/dracut.log_ is not
 443     writable
 444
 445 _/etc/dracut.conf_::
 446     see dracut.conf5
 447
 448 _/etc/dracut.conf.d/*.conf_::
 449     see dracut.conf5
 450
 451 _/usr/lib/dracut/dracut.conf.d/*.conf_::
 452     see dracut.conf5
 453
 454 Configuration in the initramfs
 455 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 456 _/etc/conf.d/_::
 457     Any files found in _/etc/conf.d/_ will be sourced in the initramfs to
 458     set initial values. Command line options will override these values
 459     set in the configuration files.
 460
 461 _/etc/cmdline_::
 462     Can contain additional command line options. Deprecated, better use /etc/cmdline.d/*.conf.
 463
 464 _/etc/cmdline.d/*.conf::
 465     Can contain additional command line options.
 466
 467 AVAILABILITY
 468 ------------
 469 The dracut command is part of the dracut package and is available from
 470 link:$$https://dracut.wiki.kernel.org$$[https://dracut.wiki.kernel.org]
 471
 472 AUTHORS
 473 -------
 474 Harald Hoyer
 475
 476 Victor Lowther
 477
 478 Philippe Seewer
 479
 480 Warren Togami
 481
 482 Amadeusz Żołnowski
 483
 484 Jeremy Katz
 485
 486 David Dillow
 487
 488 Will Woods
 489
 490 SEE ALSO
 491 --------
 492 *dracut.cmdline*(7) *dracut.conf*(5)