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 **--early-microcode**::
 229     Combine early microcode with ramdisk
 230
 231 **--no-early-microcode**::
 232     Do not combine early microcode with ramdisk
 233
 234 **--print-cmdline**::
 235     print the kernel command line for the current disk layout
 236
 237 **--mdadmconf**::
 238     include local _/etc/mdadm.conf_
 239
 240 **--nomdadmconf**::
 241     do not include local _/etc/mdadm.conf_
 242
 243 **--lvmconf**::
 244     include local _/etc/lvm/lvm.conf_
 245
 246 **--nolvmconf**::
 247     do not include local _/etc/lvm/lvm.conf_
 248
 249 **--fscks** [LIST]::
 250     add a space-separated list of fsck tools, in addition to _dracut.conf_'s
 251     specification; the installation is opportunistic (non-existing tools are
 252     ignored)
 253 +
 254 [NOTE]
 255 ===============================
 256 If [LIST] has multiple arguments, then you have to put these in quotes. For
 257 example:
 258 ----
 259 # dracut --fscks "fsck.foo barfsck"  ...
 260 ----
 261 ===============================
 262
 263 **--nofscks**::
 264     inhibit installation of any fsck tools
 265
 266 **--strip**::
 267     strip binaries in the initramfs (default)
 268
 269 **--nostrip**::
 270     do not strip binaries in the initramfs
 271
 272 **--prelink**::
 273     prelink binaries in the initramfs (default)
 274
 275 **--noprelink**::
 276     do not prelink binaries in the initramfs
 277
 278 **--hardlink**::
 279     hardlink files in the initramfs (default)
 280
 281 **--nohardlink**::
 282     do not hardlink files in the initramfs
 283
 284 **--prefix** _<dir>_::
 285     prefix initramfs files with the specified directory
 286
 287 **--noprefix**::
 288     do not prefix initramfs files (default)
 289
 290 **-h, --help**::
 291     display help text and exit.
 292
 293 **--debug**::
 294     output debug information of the build process
 295
 296 **-v, --verbose**::
 297     increase verbosity level (default is info(4))
 298
 299 **-q, --quiet**:: decrease verbosity level (default is info(4))
 300
 301 **-c, --conf** _<dracut configuration file>_::
 302     specify configuration file to use.
 303 +
 304 Default:
 305    _/etc/dracut.conf_
 306
 307 **--confdir** _<configuration directory>_::
 308     specify configuration directory to use.
 309 +
 310 Default:
 311    _/etc/dracut.conf.d_
 312
 313 **--tmpdir** _<temporary directory>_::
 314     specify temporary directory to use.
 315 +
 316 Default:
 317    _/var/tmp_
 318
 319 **--sshkey** _<sshkey file>_:: ssh key file used with ssh-client module.
 320
 321 **-l, --local**::
 322     activates the local mode. dracut will use modules from the current working
 323     directory instead of the system-wide installed modules in
 324     _/usr/lib/dracut/modules.d_.
 325     This is useful when running dracut from a git checkout.
 326
 327 **-H, --hostonly**::
 328     Host-Only mode: Install only what is needed for booting the local host
 329     instead of a generic host and generate host-specific configuration.
 330 +
 331 [WARNING]
 332 ====
 333 If chrooted to another root other than the real root device, use "--fstab" and
 334 provide a valid _/etc/fstab_.
 335 ====
 336
 337 **-N, --no-hostonly**::
 338     Disable Host-Only mode
 339
 340 **--persistent-policy** _<policy>_::
 341     Use _<policy>_ to address disks and partitions.
 342     _<policy>_ can be any directory name found in /dev/disk.
 343     E.g. "by-uuid", "by-label"
 344
 345 **--fstab**::
 346     Use _/etc/fstab_ instead of _/proc/self/mountinfo_.
 347
 348 **--add-fstab** _<filename>_ ::
 349     Add entries of _<filename>_ to the initramfs /etc/fstab.
 350
 351 **--mount** "_<device>_ _<mountpoint>_ _<filesystem type>_ _<filesystem options>_"::
 352     Mount _<device>_ on _<mountpoint>_ with _<filesystem type>_ and _<filesystem
 353     options>_ in the initramfs
 354
 355 **--add-device** _<device>_ ::
 356     Bring up _<device>_ in initramfs, _<device>_ should be the device name.
 357     This can be useful in hostonly mode for resume support when your swap is on
 358     LVM or an encrypted partition.
 359     [NB --device can be used for compatibility with earlier releases]
 360
 361 **-i, --include** _<SOURCE>_ _<TARGET>_::
 362     include the files in the SOURCE directory into the
 363     TARGET directory in the final initramfs. If SOURCE is a file, it will be
 364     installed to TARGET in the final initramfs. This parameter can be specified
 365     multiple times.
 366
 367 **-I, --install** _<file list>_::
 368     install the space separated list of files into the initramfs.
 369 +
 370 [NOTE]
 371 ===============================
 372 If [LIST] has multiple arguments, then you have to put these in quotes. For
 373 example:
 374 ----
 375 # dracut --install "/bin/foo /sbin/bar"  ...
 376 ----
 377 ===============================
 378
 379 **--gzip**::
 380     Compress the generated initramfs using gzip. This will be done by default,
 381     unless another compression option or --no-compress is passed. Equivalent to
 382     "--compress=gzip -9"
 383
 384 **--bzip2**::
 385     Compress the generated initramfs using bzip2.
 386 +
 387 [WARNING]
 388 ====
 389 Make sure your kernel has bzip2 decompression support compiled in, otherwise you
 390 will not be able to boot. Equivalent to "--compress=bzip2"
 391 ====
 392
 393 **--lzma**::
 394     Compress the generated initramfs using lzma.
 395 +
 396 [WARNING]
 397 ====
 398 Make sure your kernel has lzma decompression support compiled in, otherwise you
 399 will not be able to boot. Equivalent to "lzma --compress=lzma -9"
 400 ====
 401
 402 **--xz**::
 403     Compress the generated initramfs using xz.
 404 +
 405 [WARNING]
 406 ====
 407 Make sure your kernel has xz decompression support compiled in, otherwise you
 408 will not be able to boot. Equivalent to "lzma --compress=xz --check=crc32 --lzma2=dict=1MiB"
 409 ====
 410
 411 **--compress** _<compressor>_::
 412     Compress the generated initramfs using the passed compression program. If
 413     you pass it just the name of a compression program, it will call that
 414     program with known-working arguments. If you pass a quoted string with
 415     arguments, it will be called with exactly those arguments. Depending on what
 416     you pass, this may result in an initramfs that the kernel cannot decompress.
 417
 418 **--no-compress**::
 419     Do not compress the generated initramfs. This will override any other
 420     compression options.
 421
 422 **--list-modules**::
 423     List all available dracut modules.
 424
 425 **-M, --show-modules**::
 426     Print included module's name to standard output during build.
 427
 428 **--keep**::
 429     Keep the initramfs temporary directory for debugging purposes.
 430
 431 **--printsize**::
 432     Print out the module install size
 433
 434 **--profile**:
 435     Output profile information of the build process
 436
 437 **--ro-mnt**:
 438     Mount / and /usr read-only by default.
 439
 440 **-L, --stdlog** _<level>_::
 441     [0-6] Specify logging level (to standard error)
 442 ----
 443           0 - suppress any messages
 444           1 - only fatal errors
 445           2 - all errors
 446           3 - warnings
 447           4 - info
 448           5 - debug info (here starts lots of output)
 449           6 - trace info (and even more)
 450 ----
 451
 452 **--regenerate-all**::
 453     Regenerate all initramfs images at the default location with the kernel versions found on the system.
 454     Additional parameters are passed through.
 455
 456 FILES
 457 -----
 458 _/var/log/dracut.log_::
 459     logfile of initramfs image creation
 460
 461 _/tmp/dracut.log_::
 462     logfile of initramfs image creation, if _/var/log/dracut.log_ is not
 463     writable
 464
 465 _/etc/dracut.conf_::
 466     see dracut.conf5
 467
 468 _/etc/dracut.conf.d/*.conf_::
 469     see dracut.conf5
 470
 471 _/usr/lib/dracut/dracut.conf.d/*.conf_::
 472     see dracut.conf5
 473
 474 Configuration in the initramfs
 475 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 476 _/etc/conf.d/_::
 477     Any files found in _/etc/conf.d/_ will be sourced in the initramfs to
 478     set initial values. Command line options will override these values
 479     set in the configuration files.
 480
 481 _/etc/cmdline_::
 482     Can contain additional command line options. Deprecated, better use /etc/cmdline.d/*.conf.
 483
 484 _/etc/cmdline.d/*.conf::
 485     Can contain additional command line options.
 486
 487 AVAILABILITY
 488 ------------
 489 The dracut command is part of the dracut package and is available from
 490 link:$$https://dracut.wiki.kernel.org$$[https://dracut.wiki.kernel.org]
 491
 492 AUTHORS
 493 -------
 494 Harald Hoyer
 495
 496 Victor Lowther
 497
 498 Philippe Seewer
 499
 500 Warren Togami
 501
 502 Amadeusz Żołnowski
 503
 504 Jeremy Katz
 505
 506 David Dillow
 507
 508 Will Woods
 509
 510 SEE ALSO
 511 --------
 512 *dracut.cmdline*(7) *dracut.conf*(5)