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