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