6 :man version: {version}
10 dracut.cmdline - dracut kernel command line options
14 The root device used by the kernel is specified in the boot configuration
15 file on the kernel command line, as always.
17 The traditional _root=/dev/sda1_ style device specification is allowed, but not
18 encouraged. The root device should better be identified by LABEL or UUID. If a
19 label is used, as in _root=LABEL=<label_of_root>_ the initramfs will search all
20 available devices for a filesystem with the appropriate label, and mount that
21 device as the root filesystem. _root=UUID=<uuidnumber>_ will mount the partition
22 with that UUID as the root filesystem.
24 In the following all kernel command line parameters, which are processed by
25 dracut, are described.
27 "rd.*" parameters mentioned without "=" are boolean parameters. They can be
28 turned on/off by setting them to {0|1}. If the assignment with "=" is missing
29 "=1" is implied. For example _rd.info_ can be turned off with _rd.info=0_ or
30 turned on with _rd.info=1_ or _rd.info_. The last value in the kernel command
31 line is the value, which is honored.
35 **init=**__<path to real init>__::
36 specify the path to the init program to be started after the initramfs has
39 **root=**__<path to blockdevice>__::
40 specify the block device to use as the root filesystem.
46 root=/dev/disk/by-path/pci-0000:00:1f.1-scsi-0:0:1:0-part1
47 root=/dev/disk/by-label/Root
49 root=/dev/disk/by-uuid/3f5ad593-4546-4a94-a374-bcfb68aa11f7
50 root=UUID=3f5ad593-4546-4a94-a374-bcfb68aa11f7
51 root=PARTUUID=3f5ad593-4546-4a94-a374-bcfb68aa11f7
54 **rootfstype=**__<filesystem type>__:: "auto" if not specified.
62 **rootflags=**__<mount options>__::
63 specify additional mount options for the root filesystem. If not set,
64 _/etc/fstab_ of the real root will be parsed for special mount options and
68 force mounting _/_ and _/usr_ (if it is a separate device) read-only. If
69 none of ro and rw is present, both are mounted according to _/etc/fstab_.
72 force mounting _/_ and _/usr_ (if it is a separate device) read-write.
75 **rootfallback=**__<path to blockdevice>__::
76 specify the block device to use as the root filesystem, if the normal root
77 cannot be found. This can only be a simple block device with a simple file
78 system, for which the filesystem driver is either compiled in, or added
79 manually to the initramfs. This parameter can be specified multiple times.
81 **rd.auto** **rd.auto=1**::
82 enable autoassembly of special devices like cryptoLUKS, dmraid, mdraid or
83 lvm. Default is off as of dracut version >= 024.
86 removes all compiled in configuration of the host system the initramfs image
87 was built on. This helps booting, if any disk layout changed, especially in
88 combination with rd.auto or other parameters specifying the layout.
91 prompts the user for additional kernel command line parameters
94 do not honor special mount options for the root filesystem found in
95 _/etc/fstab_ of the real root.
97 **resume=**__<path to resume partition>__::
98 resume from a swap partition
103 resume=/dev/disk/by-path/pci-0000:00:1f.1-scsi-0:0:1:0-part1
104 resume=/dev/disk/by-uuid/3f5ad593-4546-4a94-a374-bcfb68aa11f7
105 resume=UUID=3f5ad593-4546-4a94-a374-bcfb68aa11f7
109 skip fsck for rootfs and _/usr_. If you're mounting _/usr_ read-only and
110 the init system performs fsck before remount, you might want to use this
111 option to avoid duplication.
116 Using iso-scan/filename with a Fedora/Red Hat/CentOS Live iso should just work
117 by copying the original kernel cmdline parameters.
122 menuentry 'Live Fedora 20' --class fedora --class gnu-linux --class gnu --class os {
123 set isolabel=Fedora-Live-LXDE-x86_64-20-1
124 set isofile="/boot/iso/Fedora-Live-LXDE-x86_64-20-1.iso"
125 loopback loop $isofile
126 linux (loop)/isolinux/vmlinuz0 boot=isolinux iso-scan/filename=$isofile root=live:LABEL=$isolabel ro rd.live.image quiet rhgb
127 initrd (loop)/isolinux/initrd0.img
133 **rd.emergency=**__[reboot|poweroff|halt]__::
134 specify, what action to execute in case of a critical failure. rd.shell=0 also
137 **rd.driver.blacklist=**__<drivername>__[,__<drivername>__,...]::
138 do not load kernel module <drivername>. This parameter can be specified
141 **rd.driver.pre=**__<drivername>__[,__<drivername>__,...]::
142 force loading kernel module <drivername>. This parameter can be specified
145 **rd.driver.post=**__<drivername>__[,__<drivername>__,...]::
146 force loading kernel module <drivername> after all automatic loading modules
147 have been loaded. This parameter can be specified multiple times.
149 **rd.retry=**__<seconds>__::
150 specify how long dracut should retry the initqueue to configure devices.
151 The default is 30 seconds. After 2/3 of the time, degraded raids are force
152 started. If you have hardware, which takes a very long time to announce its
153 drives, you might want to extend this value.
155 **rd.timeout=**__<seconds>__::
156 specify how long dracut should wait for devices to appear. The
157 default is '0', which means 'forever'. Note that this timeout
158 should be longer than rd.retry to allow for proper configuration.
161 accept self-signed certificates for ssl downloads.
163 **rd.ctty=**__<terminal device>__::
164 specify the controlling terminal for the console.
165 This is useful, if you have multiple "console=" arguments.
167 [[dracutkerneldebug]]
170 If you are dropped to an emergency shell, the file
171 _/run/initramfs/rdsosreport.txt_ is created, which can be saved to a (to be
172 mounted by hand) partition (usually /boot) or a USB stick. Additional debugging
173 info can be produced by adding **rd.debug** to the kernel command line.
174 _/run/initramfs/rdsosreport.txt_ contains all logs and the output of some tools.
175 It should be attached to any report about dracut problems.
178 print informational output though "quiet" is set
181 allow dropping to a shell, if root mounting fails
184 set -x for the dracut shell.
185 If systemd is active in the initramfs, all output is logged to the systemd
186 journal, which you can inspect with "journalctl -ab".
187 If systemd is not active, the logs are written to dmesg and
188 _/run/initramfs/init.log_.
189 If "quiet" is set, it also logs to the console.
191 **rd.memdebug=[0-4]**::
192 Print memory usage info at various points, set the verbose level from 0 to 4.
194 Higher level means more debugging output:
198 1 - partial /proc/meminfo
200 3 - /proc/meminfo + /proc/slabinfo
201 4 - /proc/meminfo + /proc/slabinfo + tracekomem
202 NOTE: tracekomem is a shell script utilizing kernel trace to track
203 the rough total memory consumption of kernel modules during
204 loading. It may override other trace configurations.
208 drop to a shell at the end
210 **rd.break=**__{cmdline|pre-udev|pre-trigger|initqueue|pre-mount|mount|pre-pivot|cleanup}__::
211 drop to a shell on defined breakpoint
214 set udev to loglevel info
217 set udev to loglevel debug
221 **rd.vconsole.keymap=**__<keymap base file name>__::
222 keyboard translation table loaded by loadkeys; taken from keymaps directory;
223 will be written as KEYMAP to _/etc/vconsole.conf_ in the initramfs.
228 rd.vconsole.keymap=de-latin1-nodeadkeys
231 **rd.vconsole.keymap.ext=**__<list of keymap base file names>__::
232 list of extra keymaps to bo loaded (sep. by space); will be written as
233 EXT_KEYMAP to _/etc/vconsole.conf_ in the initramfs
235 **rd.vconsole.unicode**::
236 boolean, indicating UTF-8 mode; will be written as UNICODE to
237 _/etc/vconsole.conf_ in the initramfs
239 **rd.vconsole.font=**__<font base file name>__::
240 console font; taken from consolefonts directory; will be written as FONT to
241 _/etc/vconsole.conf_ in the initramfs.
246 rd.vconsole.font=eurlatgr
249 **rd.vconsole.font.map=**__<console map base file name>__::
250 see description of '-m' parameter in setfont manual; taken from consoletrans
251 directory; will be written as FONT_MAP to _/etc/vconsole.conf_ in the
254 **rd.vconsole.font.unimap=**__<unicode table base file name>__::
255 see description of '-u' parameter in setfont manual; taken from unimaps
256 directory; will be written as FONT_UNIMAP to _/etc/vconsole.conf_ in the
259 **rd.locale.LANG=**__<locale>__::
260 taken from the environment; if no UNICODE is defined we set its value in
261 basis of LANG value (whether it ends with ".utf8" (or similar) or not); will
262 be written as LANG to _/etc/locale.conf_ in the initramfs.
267 rd.locale.LANG=pl_PL.utf8
270 **rd.locale.LC_ALL=**__<locale>__::
271 taken from the environment; will be written as LC_ALL to _/etc/locale.conf_
277 disable LVM detection
279 **rd.lvm.vg=**__<volume group name>__::
280 only activate the volume groups with the given name. rd.lvm.vg can be
281 specified multiple times on the kernel command line.
283 **rd.lvm.lv=**__<logical volume name>__::
284 only activate the logical volumes with the given name. rd.lvm.lv can be
285 specified multiple times on the kernel command line.
288 remove any _/etc/lvm/lvm.conf_, which may exist in the initramfs
293 disable crypto LUKS detection
295 **rd.luks.uuid=**__<luks uuid>__::
296 only activate the LUKS partitions with the given UUID. Any "luks-" of the
297 LUKS UUID is removed before comparing to _<luks uuid>_.
298 The comparisons also matches, if _<luks uuid>_ is only the beginning of the
299 LUKS UUID, so you don't have to specify the full UUID.
300 This parameter can be specified multiple times.
302 **rd.luks.allow-discards=**__<luks uuid>__::
303 Allow using of discards (TRIM) requests for LUKS partitions with the given
304 UUID. Any "luks-" of the LUKS UUID is removed before comparing to
305 _<luks uuid>_. The comparisons also matches, if _<luks uuid>_ is only the
306 beginning of the LUKS UUID, so you don't have to specify the full UUID.
307 This parameter can be specified multiple times.
309 **rd.luks.allow-discards**::
310 Allow using of discards (TRIM) requests on all LUKS partitions.
312 **rd.luks.crypttab=0**::
313 do not check, if LUKS partition is in _/etc/crypttab_
315 **rd.luks.timeout=**__<seconds>__::
316 specify how long dracut should wait when waiting for the user to enter the
317 password. This avoid blocking the boot if no password is entered. It does
318 not apply to luks key. The default is '0', which means 'forever'.
320 crypto LUKS - key on removable device support
321 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
323 NB: If systemd is included in the dracut initrd, dracut's built in
324 removable device keying support won't work. systemd will prompt for
325 a password from the console even if you've supplied **rd.luks.key**.
326 You may be able to use standard systemd *fstab*(5) syntax to
327 get the same effect. If you do need **rd.luks.key** to work,
328 you will have to exclude the "systemd" dracut module and any modules
329 that depend on it. See *dracut.conf*(5) and
330 https://bugzilla.redhat.com/show_bug.cgi?id=905683 for more
333 **rd.luks.key=**_<keypath>[:<keydev>[:<luksdev>]]_::
334 _<keypath>_ is the pathname of a key file, relative to the root
335 of the filesystem on some device. It's REQUIRED. When
336 _<keypath>_ ends with '.gpg' it's considered to be key encrypted
337 symmetrically with GPG. You will be prompted for the GPG password on
338 boot. GPG support comes with the 'crypt-gpg' module, which needs to be
341 _<keydev>_ identifies the device on which the key file resides. It may
342 be the kernel name of the device (should start with "/dev/"), a UUID
343 (prefixed with "UUID=") or a label (prefix with "LABEL="). You don't
344 have to specify a full UUID. Just its beginning will suffice, even if
345 its ambiguous. All matching devices will be probed. This parameter is
346 recommended, but not required. If it's not present, all block devices will
347 be probed, which may significantly increase boot time.
349 If _<luksdev>_ is given, the specified key will only be used for
350 the specified LUKS device. Possible values are the same as for
351 _<keydev>_. Unless you have several LUKS devices, you don't have to
352 specify this parameter. The simplest usage is:
357 rd.luks.key=/foo/bar.key
360 As you see, you can skip colons in such a case.
363 ===============================
364 Your LUKS partition must match your key file.
366 dracut provides keys to cryptsetup with _-d_ (an older alias for
367 _--key-file_). This uses the entire binary
368 content of the key file as part of the secret. If
369 you pipe a password into cryptsetup *without* _-d_ or _--key-file_,
370 it will be treated as text user input, and only characters before
371 the first newline will be used. Therefore, when you're creating
372 an encrypted partition for dracut to mount, and you pipe a key into
373 _cryptsetup luksFormat_,you must use _-d -_.
375 Here is an example for a key encrypted with GPG (warning:
376 _--batch-mode_ will overwrite the device without asking for
381 gpg --quiet --decrypt rootkey.gpg | \
382 cryptsetup --batch-mode --key-file - \
383 luksFormat /dev/sda47
386 If you use unencrypted key files, just use the key file pathname
387 instead of the standard input. For a random key with 256 bits of
388 entropy, you might use:
392 head -32c /dev/urandom > rootkey.key
393 cryptsetup --batch-mode --key-file rootkey.key \
394 luksFormat /dev/sda47
396 ===============================
401 disable MD RAID detection
404 disable MD RAID for imsm/isw raids, use DM RAID instead
407 disable MD RAID for SNIA ddf raids, use DM RAID instead
410 ignore mdadm.conf included in initramfs
412 **rd.md.waitclean=1**::
413 wait for any resync, recovery, or reshape activity to finish before
416 **rd.md.uuid=**__<md raid uuid>__::
417 only activate the raid sets with the given UUID. This parameter can be
418 specified multiple times.
423 disable DM RAID detection
425 **rd.dm.uuid=**__<dm raid uuid>__::
426 only activate the raid sets with the given UUID. This parameter can be
427 specified multiple times.
432 disable multipath detection
439 **boot=**__<boot device>__::
440 specify the device, where /boot is located.
446 boot=/dev/disk/by-path/pci-0000:00:1f.1-scsi-0:0:1:0-part1
451 **rd.fips.skipkernel**::
452 skip checksum check of the kernel image. Useful, if the kernel image is not
453 in a separate boot partition.
459 =====================
460 It is recommended to either bind an interface to a MAC with the **ifname**
461 argument, or to use the systemd-udevd predictable network interface names.
463 Predictable network interface device names based on:
465 - firmware/bios-provided index numbers for on-board devices
466 - firmware-provided pci-express hotplug slot index number
467 - physical/geographical location of the hardware
468 - the interface's MAC address
471 http://www.freedesktop.org/wiki/Software/systemd/PredictableNetworkInterfaceNames
473 Two character prefixes based on the type of interface:
481 o<index>:: on-board device index number
482 s<slot>[f<function>][d<dev_id>]:: hotplug slot index number
484 [P<domain>]p<bus>s<slot>[f<function>][d<dev_id>]:: PCI geographical location
485 [P<domain>]p<bus>s<slot>[f<function>][u<port>][..][c<config>][i<interface>]:: USB port number chain
487 All multi-function PCI devices will carry the [f<function>] number in the
488 device name, including the function 0 device.
490 When using PCI geography, The PCI domain is only prepended when it is not 0.
492 For USB devices the full chain of port numbers of hubs is composed. If the
493 name gets longer than the maximum number of 15 characters, the name is not
495 The usual USB configuration == 1 and interface == 0 values are suppressed.
497 PCI ethernet card with firmware index "1"::
500 PCI ethernet card in hotplug slot with firmware index number::
503 PCI ethernet multi-function card with 2 ports::
510 USB built-in 3G modem::
515 =====================
517 **ip=**__{dhcp|on|any|dhcp6|auto6|either6}__::
518 dhcp|on|any::: get ip from dhcp server from all interfaces. If root=dhcp,
519 loop sequentially through all interfaces (eth0, eth1, ...) and use the first
520 with a valid DHCP root-path.
522 auto6::: IPv6 autoconfiguration
526 either6::: if auto6 fails, then dhcp6
528 **ip=**__<interface>__:__{dhcp|on|any|dhcp6|auto6}__[:[__<mtu>__][:__<macaddr>__]]::
529 This parameter can be specified multiple times.
531 =====================
532 dhcp|on|any|dhcp6::: get ip from dhcp server on a specific interface
533 auto6::: do IPv6 autoconfiguration
534 <macaddr>::: optionally **set** <macaddr> on the <interface>. This
535 cannot be used in conjunction with the **ifname** argument for the
537 =====================
539 **ip=**__<client-IP>__:[__<peer>__]:__<gateway-IP>__:__<netmask>__:__<client_hostname>__:__<interface>__:__{none|off|dhcp|on|any|dhcp6|auto6|ibft}__[:[__<mtu>__][:__<macaddr>__]]::
540 explicit network configuration. If you want do define a IPv6 address, put it
541 in brackets (e.g. [2001:DB8::1]). This parameter can be specified multiple
542 times. __<peer>__ is optional and is the address of the remote endpoint
543 for pointopoint interfaces and it may be followed by a slash and a decimal
544 number, encoding the network prefix length.
546 =====================
547 <macaddr>::: optionally **set** <macaddr> on the <interface>. This
548 cannot be used in conjunction with the **ifname** argument for the
550 =====================
552 **ip=**__<client-IP>__:[__<peer>__]:__<gateway-IP>__:__<netmask>__:__<client_hostname>__:__<interface>__:__{none|off|dhcp|on|any|dhcp6|auto6|ibft}__[:[__<dns1>__][:__<dns2>__]]::
553 explicit network configuration. If you want do define a IPv6 address, put it
554 in brackets (e.g. [2001:DB8::1]). This parameter can be specified multiple
555 times. __<peer>__ is optional and is the address of the remote endpoint
556 for pointopoint interfaces and it may be followed by a slash and a decimal
557 number, encoding the network prefix length.
559 **ifname=**__<interface>__:__<MAC>__::
560 Assign network device name <interface> (i.e. "bootnet") to the NIC with
563 WARNING: Do **not** use the default kernel naming scheme for the interface name,
564 as it can conflict with the kernel names. So, don't use "eth[0-9]+" for the
565 interface name. Better name it "bootnet" or "bluesocket".
567 **rd.route=**__<net>__/__<netmask>__:__<gateway>__[:__<interface>__]::
568 Add a static route with route options, which are separated by a colon.
569 IPv6 addresses have to be put in brackets.
574 rd.route=192.168.200.0/24:192.168.100.222:ens10
575 rd.route=192.168.200.0/24:192.168.100.222
576 rd.route=192.168.200.0/24::ens10
577 rd.route=[2001:DB8:3::/8]:[2001:DB8:2::1]:ens10
580 **bootdev=**__<interface>__::
581 specify network interface to use routing and netroot information from.
582 Required if multiple ip= lines are used.
584 **BOOTIF=**__<MAC>__::
585 specify network interface to use routing and netroot information from.
588 Disable BOOTIF parsing, which is provided by PXE
590 **nameserver=**__<IP>__ [**nameserver=**__<IP>__ ...]::
591 specify nameserver(s) to use
594 Disable DNS setting of DHCP parameters.
597 boolean, turn off biosdevname network interface renaming
600 boolean, bring up network even without netroot set
602 **vlan=**__<vlanname>__:__<phydevice>__::
603 Setup vlan device named <vlanname> on <phydeivce>.
604 We support the four styles of vlan names: VLAN_PLUS_VID (vlan0005),
605 VLAN_PLUS_VID_NO_PAD (vlan5), DEV_PLUS_VID (eth0.0005),
606 DEV_PLUS_VID_NO_PAD (eth0.5)
608 **bond=**__<bondname>__[:__<bondslaves>__:[:__<options>__[:<mtu>]]]::
609 Setup bonding device <bondname> on top of <bondslaves>.
610 <bondslaves> is a comma-separated list of physical (ethernet) interfaces.
611 <options> is a comma-separated list on bonding options (modinfo bonding for
612 details) in format compatible with initscripts. If <options> includes
613 multi-valued arp_ip_target option, then its values should be separated by
614 semicolon. if the mtu is specified, it will be set on the bond master.
615 Bond without parameters assumes
616 bond=bond0:eth0,eth1:mode=balance-rr
618 **team=**__<teammaster>__:__<teamslaves>__::
619 Setup team device <teammaster> on top of <teamslaves>.
620 <teamslaves> is a comma-separated list of physical (ethernet) interfaces.
622 **bridge=**__<bridgename>__:__<ethnames>__::
623 Setup bridge <bridgename> with <ethnames>. <ethnames> is a comma-separated
624 list of physical (ethernet) interfaces. Bridge without parameters assumes
629 **root=**\[_<server-ip>_:]__<root-dir>__[:__<nfs-options>__]::
630 mount nfs share from <server-ip>:/<root-dir>, if no server-ip is given, use
631 dhcp next_server. If server-ip is an IPv6 address it has to be put in
632 brackets, e.g. [2001:DB8::1]. NFS options can be appended with the prefix
633 ":" or "," and are separated by ",".
635 **root=**nfs:\[_<server-ip>_:]__<root-dir>__[:__<nfs-options>__], **root=**nfs4:\[_<server-ip>_:]__<root-dir>__[:__<nfs-options>__], **root=**__{dhcp|dhcp6}__::
636 root=dhcp alone directs initrd to look at the DHCP root-path where NFS
637 options can be specified.
642 root-path=<server-ip>:<root-dir>[,<nfs-options>]
643 root-path=nfs:<server-ip>:<root-dir>[,<nfs-options>]
644 root-path=nfs4:<server-ip>:<root-dir>[,<nfs-options>]
647 **root=**_/dev/nfs_ nfsroot=\[_<server-ip>_:]__<root-dir>__[:__<nfs-options>__]::
648 _Deprecated!_ kernel Documentation_/filesystems/nfsroot.txt_ defines this
649 method. This is supported by dracut, but not recommended.
651 **rd.nfs.domain=**__<NFSv4 domain name>__::
652 Set the NFSv4 domain name. Will override the settings in _/etc/idmap.conf_.
654 **rd.net.dhcp.retry=**__<cnt>__::
655 If this option is set, dracut will try to connect via dhcp <cnt> times before failing.
658 **rd.net.timeout.dhcp=**__<arg>__::
659 If this option is set, dhclient is called with "-timeout <arg>".
661 **rd.net.timeout.iflink=**__<seconds>__::
662 Wait <seconds> until link shows up. Default is 60 seconds.
664 **rd.net.timeout.ifup=**__<seconds>__::
665 Wait <seconds> until link has state "UP". Default is 20 seconds.
667 **rd.net.timeout.route=**__<seconds>__::
668 Wait <seconds> until route shows up. Default is 20 seconds.
670 **rd.net.timeout.ipv6dad=**__<seconds>__::
671 Wait <seconds> until IPv6 DAD is finished. Default is 50 seconds.
673 **rd.net.timeout.ipv6auto=**__<seconds>__::
674 Wait <seconds> until IPv6 automatic addresses are assigned. Default is 40 seconds.
676 **rd.net.timeout.carrier=**__<seconds>__::
677 Wait <seconds> until carrier is recognized. Default is 10 seconds.
681 **root=**cifs://[__<username>__[:__<password>__]@]__<server-ip>__:__<root-dir>__::
682 mount cifs share from <server-ip>:/<root-dir>, if no server-ip is given, use
683 dhcp next_server. if server-ip is an IPv6 address it has to be put in
684 brackets, e.g. [2001:DB8::1]. If a username or password are not specified
685 as part of the root, then they must be passed on the command line through
688 WARNING: Passwords specified on the kernel command line are visible for all
689 users via the file _/proc/cmdline_ and via dmesg or can be sniffed on the
690 network, when using DHCP with DHCP root-path.
692 **cifsuser**=__<username>__::
693 Set the cifs username, if not specified as part of the root.
695 **cifspass**=__<password>__::
696 Set the cifs password, if not specified as part of the root.
698 WARNING: Passwords specified on the kernel command line are visible for all
699 users via the file _/proc/cmdline_ and via dmesg or can be sniffed on the
700 network, when using DHCP with DHCP root-path.
704 **root=**iscsi:[__<username>__:__<password>__[:__<reverse>__:__<password>__]@][__<servername>__]:[__<protocol>__]:[__<port>__][:[__<iscsi_iface_name>__]:[__<netdev_name>__]]:[__<LUN>__]:__<targetname>__::
705 protocol defaults to "6", LUN defaults to "0". If the "servername" field is
706 provided by BOOTP or DHCP, then that field is used in conjunction with other
707 associated fields to contact the boot server in the Boot stage. However, if
708 the "servername" field is not provided, then the "targetname" field is then
709 used in the Discovery Service stage in conjunction with other associated
711 link:$$http://tools.ietf.org/html/rfc4173#section-5$$[rfc4173].
713 WARNING: Passwords specified on the kernel command line are visible for all
714 users via the file _/proc/cmdline_ and via dmesg or can be sniffed on the
715 network, when using DHCP with DHCP root-path.
720 root=iscsi:192.168.50.1::::iqn.2009-06.dracut:target0
723 If servername is an IPv6 address, it has to be put in brackets:
728 root=iscsi:[2001:DB8::1]::::iqn.2009-06.dracut:target0
731 **root=**__???__ **netroot=**iscsi:[__<username>__:__<password>__[:__<reverse>__:__<password>__]@][__<servername>__]:[__<protocol>__]:[__<port>__][:[__<iscsi_iface_name>__]:[__<netdev_name>__]]:[__<LUN>__]:__<targetname>__ ...::
732 multiple netroot options allow setting up multiple iscsi disks:
738 netroot=iscsi:192.168.50.1::::iqn.2009-06.dracut:target0
739 netroot=iscsi:192.168.50.1::::iqn.2009-06.dracut:target1
742 If servername is an IPv6 address, it has to be put in brackets:
747 netroot=iscsi:[2001:DB8::1]::::iqn.2009-06.dracut:target0
750 WARNING: Passwords specified on the kernel command line are visible for all
751 users via the file _/proc/cmdline_ and via dmesg or can be sniffed on the
752 network, when using DHCP with DHCP root-path.
753 You may want to use rd.iscsi.firmware.
755 **root=**__???__ **rd.iscsi.initiator=**__<initiator>__ **rd.iscsi.target.name=**__<target name>__ **rd.iscsi.target.ip=**__<target ip>__ **rd.iscsi.target.port=**__<target port>__ **rd.iscsi.target.group=**__<target group>__ **rd.iscsi.username=**__<username>__ **rd.iscsi.password=**__<password>__ **rd.iscsi.in.username=**__<in username>__ **rd.iscsi.in.password=**__<in password>__::
756 manually specify all iscsistart parameter (see **+iscsistart --help+**)
758 WARNING: Passwords specified on the kernel command line are visible for all
759 users via the file _/proc/cmdline_ and via dmesg or can be sniffed on the
760 network, when using DHCP with DHCP root-path.
761 You may want to use rd.iscsi.firmware.
763 **root=**_???_ **netroot=**iscsi **rd.iscsi.firmware=1**::
764 will read the iscsi parameter from the BIOS firmware
766 **rd.iscsi.login_retry_max=**__<num>__::
767 maximum number of login retries
769 **rd.iscsi.param=**__<param>__::
770 <param> will be passed as "--param <param>" to iscsistart.
771 This parameter can be specified multiple times.
776 "netroot=iscsi rd.iscsi.firmware=1 rd.iscsi.param=node.session.timeo.replacement_timeout=30"
783 iscsistart -b --param node.session.timeo.replacement_timeout=30
786 **rd.iscsi.ibft** **rd.iscsi.ibft=1**:
787 Turn on iBFT autoconfiguration for the interfaces
789 **rd.iscsi.mp** **rd.iscsi.mp=1**:
790 Configure all iBFT interfaces, not only used for booting (multipath)
792 **rd.iscsi.waitnet=0**:
793 Turn off waiting for all interfaces to be up before trying to login to the iSCSI targets.
795 **rd.iscsi.testroute=0**:
796 Turn off checking, if the route to the iSCSI target IP is possible before trying to login.
801 disable FCoE and lldpad
803 **fcoe=**__<edd|interface|MAC>__:__{dcb|nodcb}__:__{fabric|vn2vn}__::
804 Try to connect to a FCoE SAN through the NIC specified by _<interface>_ or
805 _<MAC>_ or EDD settings. The second argument specifies if DCB
806 should be used. The optional third argument specifies whether
807 fabric or VN2VN mode should be used.
808 This parameter can be specified multiple times.
810 NOTE: letters in the MAC-address must be lowercase!
814 **root=**??? **netroot=**nbd:__<server>__:__<port/exportname>__[:__<fstype>__[:__<mountopts>__[:__<nbdopts>__]]]::
815 mount nbd share from <server>.
818 If "exportname" instead of "port" is given the standard port is used.
819 Newer versions of nbd are only supported with "exportname".
821 **root=dhcp** with **dhcp** **root-path=**nbd:__<server>__:__<port/exportname>__[:__<fstype>__[:__<mountopts>__[:__<nbdopts>__]]]::
822 root=dhcp alone directs initrd to look at the DHCP root-path where NBD
823 options can be specified. This syntax is only usable in cases where you are
824 directly mounting the volume as the rootfs.
827 If "exportname" instead of "port" is given the standard port is used.
828 Newer versions of nbd are only supported with "exportname".
833 same syntax as the kernel module parameter (s390 only)
837 **rd.zfcp=**__<zfcp adaptor device bus ID>__,__<WWPN>__,__<FCPLUN>__::
838 rd.zfcp can be specified multiple times on the kernel command
841 **rd.zfcp=**__<zfcp adaptor device bus ID>__::
842 If NPIV is enabled and the 'allow_lun_scan' parameter to the zfcp
843 module is set to 'Y' then the zfcp adaptor will be initiating a
844 scan internally and the <WWPN> and <FCPLUN> parameters can be omitted.
849 rd.zfcp=0.0.4000,0x5005076300C213e9,0x5022000000000000
854 ignore zfcp.conf included in the initramfs
858 **rd.znet=**__<nettype>__,__<subchannels>__,__<options>__::
859 The whole parameter is appended to /etc/ccw.conf, which is used on
860 RHEL/Fedora with ccw_init, which is called from udev for certain
862 rd.znet can be specified multiple times on the kernel command line.
867 rd.znet=qeth,0.0.0600,0.0.0601,0.0.0602,layer2=1,portname=foo
868 rd.znet=ctc,0.0.0600,0.0.0601,protocol=bar
873 Dracut offers multiple options for live booted images:
875 =====================
876 SquashFS with read-only filesystem image::: The system will boot with a
877 read-only filesystem from the SquashFS and apply a writable Device-mapper
878 snapshot or an OverlayFS overlay mount for the read-only base filesystem. This
879 method ensures a relatively fast boot and lower RAM usage. Users **must be
880 careful** to avoid writing too many blocks to a snapshot volume. Once the
881 blocks of the snapshot overlay are exhausted, the root filesystem becomes
882 read-only and may cause application failures. The snapshot overlay file is
883 marked 'Overflow', and a difficult recovery is required to repair and enlarge
884 the overlay offline. Non-persistent overlays are sparse files in RAM that only
885 consume content space as required blocks are allocated. They default to an
886 apparent size of 32 GiB in RAM. The size can be adjusted with the
887 **rd.live.overlay.size=** kernel command line option.
889 The filesystem structure is traditionally expected to be:
893 squashfs.img | SquashFS from LiveCD .iso
896 |- rootfs.img | Filesystem image to mount read-only
898 /bin | Live filesystem
904 For OverlayFS mount overlays, the filesystem structure may also be a direct
905 compression of the root filesystem:
909 squashfs.img | SquashFS from LiveCD .iso
911 /bin | Live filesystem
917 Dracut uses one of the overlay methods of live booting by default. No
918 additional command line options are required other than **root=live:<URL>** to
919 specify the location of your squashed filesystem.
921 - The compressed SquashFS image can be copied during boot to RAM at
922 `/run/initramfs/squashed.img` by using the **rd.live.ram=1** option.
923 - A device with a persistent overlay can be booted read-only by using the
924 **rd.live.overlay.readonly** option on the kernel command line. This will
925 either cause a temporary, writable overlay to be stacked over a read-only
926 snapshot of the root filesystem or the OverlayFS mount will use an additional
927 lower layer with the root filesystem.
929 Uncompressed live filesystem image:::
930 When the live system was installed with the '--skipcompress' option of the
931 __livecd-iso-to-disk__ installation script for Live USB devices, the root
932 filesystem image, __rootfs.img__, is expanded on installation and no SquashFS
933 is involved during boot.
935 - If **rd.live.ram=1** is used in this situation, the full, uncompressed
936 root filesystem is copied during boot to `/run/initramfs/rootfs.img` in the
939 - If **rd.live.overlay=none** is provided as a kernel command line option,
940 a writable, linear Device-mapper target is created on boot with no overlay.
942 Writable filesystem image:::
943 The system will retrieve a compressed filesystem image, extract it to
944 `/run/initramfs/fsimg/rootfs.img`, connect it to a loop device, create a
945 writable, linear Device-mapper target at `/dev/mapper/live-rw`, and mount that
946 as a writable volume at `/`. More RAM is required during boot but the live
947 filesystem is easier to manage if it becomes full. Users can make a filesystem
948 image of any size and that size will be maintained when the system boots. There
949 is no persistence of root filesystem changes between boots with this option.
951 The filesystem structure is expected to be:
955 rootfs.tgz | Compressed tarball containing filesystem image
957 /rootfs.img | Filesystem image at /run/initramfs/fsimg/
959 /bin | Live filesystem
965 To use this boot option, ensure that **rd.writable.fsimg=1** is in your kernel
966 command line and add the **root=live:<URL>** to specify the location
967 of your compressed filesystem image tarball or SquashFS image.
968 =====================
970 **rd.writable.fsimg=**1::
971 Enables writable filesystem support. The system will boot with a fully
972 writable (but non-persistent) filesystem without snapshots __(see notes above
973 about available live boot options)__. You can use the **rootflags** option to
974 set mount options for the live filesystem as well __(see documentation about
975 rootflags in the **Standard** section above)__.
976 This implies that the whole image is copied to RAM before the boot continues.
978 NOTE: There must be enough free RAM available to hold the complete image.
980 This method is very suitable for diskless boots.
982 **root=**live:__<url>__::
983 Boots a live image retrieved from __<url>__. Requires the dracut 'livenet'
984 module. Valid handlers: __http, https, ftp, torrent, tftp__.
989 root=live:http://example.com/liveboot.img
990 root=live:ftp://ftp.example.com/liveboot.img
991 root=live:torrent://example.com/liveboot.img.torrent
994 **rd.live.debug=**1::
995 Enables debug output from the live boot process.
997 **rd.live.dir=**__<path>__::
998 Specifies the directory within the boot device where the squashfs.img or
999 rootfs.img can be found. By default, this is `/LiveOS`.
1001 **rd.live.squashimg=**__<filename of SquashFS image>__::
1002 Specifies the filename for a SquashFS image of the root filesystem.
1003 By default, this is __squashfs.img__.
1006 Copy the complete image to RAM and use this for booting. This is useful
1007 when the image resides on, e.g., a DVD which needs to be ejected later on.
1009 **rd.live.overlay={**__<devspec>__[:__{<pathspec>|auto}__]|__none__}::
1010 Manage the usage of a permanent overlay.
1013 * _<devspec>_ specifies the path to a device with a mountable filesystem.
1014 * _<pathspec>_ is the path to a file within that filesystem, which shall be
1015 used to persist the changes made to the device specified by the
1016 **root=live:__<url>__** option.
1018 The default _pathspec_, when _auto_ or no _:<pathspec>_ is given, is
1019 `/<+++<b>rd.live.dir</b>+++>/overlay-<label>-<uuid>`, where _<label>_ is the
1020 device LABEL, and _<uuid>_ is the device UUID.
1021 * _none_ (the word itself) specifies that no overlay will be used, such as when
1022 an uncompressed, writable live root filesystem is available.
1024 If a persistent overlay __is detected__ at the standard LiveOS path, the
1025 overlay & overlay type detected, whether Device-mapper or OverlayFS, will be
1032 rd.live.overlay=/dev/sdb1:persistent-overlay.img
1033 rd.live.overlay=UUID=99440c1f-8daa-41bf-b965-b7240a8996f4
1036 **rd.live.overlay.size=**__<size_MiB>__::
1037 Specifies a non-persistent Device-mapper overlay size in MiB. The default is
1040 **rd.live.overlay.readonly=**1::
1041 This is used to boot with a normally read-write persistent overlay in a
1042 read-only mode. With this option, either an additional, non-persistent,
1043 writable snapshot overlay will be stacked over a read-only snapshot,
1044 `/dev/mapper/live‑ro`, of the base filesystem with the persistent overlay, or a
1045 read-only loop device, in the case of a writable __rootfs.img__, or an OverlayFS
1046 mount will use the persistent overlay directory linked at `/run/overlayfs‑r` as
1047 an additional lower layer along with the base root filesystem and apply a
1048 transient, writable upper directory overlay, in order to complete the booted
1051 **rd.live.overlay.reset=**1::
1052 Specifies that a persistent overlay should be reset on boot. All previous root
1053 filesystem changes are vacated by this action.
1055 **rd.live.overlay.thin=**1::
1056 Enables the usage of thin snapshots instead of classic dm snapshots.
1057 The advantage of thin snapshots is that they support discards, and will free
1058 blocks that are not claimed by the filesystem. In this use case, this means
1059 that memory is given back to the kernel when the filesystem does not claim it
1062 **rd.live.overlay.overlayfs=**1::
1063 Enables the use of the *OverlayFS* kernel module, if available, to provide a
1064 copy-on-write union directory for the root filesystem. OverlayFS overlays are
1065 directories of the files that have changed on the read-only base (lower)
1066 filesystem. The root filesystem is provided through a special overlay type
1067 mount that merges the lower and upper directories. If an OverlayFS upper
1068 directory is not present on the boot device, a tmpfs directory will be created
1069 at `/run/overlayfs` to provide temporary storage. Persistent storage can be
1070 provided on vfat or msdos formatted devices by supplying the OverlayFS upper
1071 directory within an embedded filesystem that supports the creation of trusted.*
1072 extended attributes and provides a valid d_type in readdir responses, such as
1073 with ext4 and xfs. On non-vfat-formatted devices, a persistent OverlayFS
1074 overlay can extend the available root filesystem storage up to the capacity of
1075 the LiveOS disk device.
1077 If a persistent overlay is detected at the standard LiveOS path, the overlay &
1078 overlay type detected, whether OverlayFS or Device-mapper, will be used.
1080 The **rd.live.overlay.readonly** option, which allows a persistent overlayfs to
1081 be mounted read-only through a higher level transient overlay directory, has
1082 been implemented through the multiple lower layers feature of OverlayFS.
1087 **rd.zipl=**__<path to blockdevice>__::
1088 Update the dracut commandline with the values found in the
1089 _dracut-cmdline.conf_ file on the given device.
1090 The values are merged into the existing commandline values
1091 and the udev events are regenerated.
1096 rd.zipl=UUID=0fb28157-99e3-4395-adef-da3f7d44835a
1101 **rd.cio_accept=**__<device-ids>__::
1102 Remove the devices listed in <device-ids> from the default
1103 cio_ignore kernel command-line settings.
1104 <device-ids> is a list of comma-separated CCW device ids.
1105 The default for this value is taken from the
1106 _/boot/zipl/active_devices.txt_ file.
1111 rd.cio_accept=0.0.0180,0.0.0800,0.0.0801,0.0.0802
1114 Plymouth Boot Splash
1115 ~~~~~~~~~~~~~~~~~~~~
1116 **plymouth.enable=0**::
1117 disable the plymouth bootsplash completely.
1120 disable the plymouth bootsplash only for the initramfs.
1124 **masterkey=**__<kernel master key path name>__::
1125 Set the path name of the kernel master key.
1130 masterkey=/etc/keys/kmk-trusted.blob
1133 **masterkeytype=**__<kernel master key type>__::
1134 Set the type of the kernel master key.
1139 masterkeytype=trusted
1142 **evmkey=**__<EVM key path name>__::
1143 Set the path name of the EVM key.
1148 evmkey=/etc/keys/evm-trusted.blob
1151 **ecryptfskey=**__<eCryptfs key path name>__::
1152 Set the path name of the eCryptfs key.
1157 ecryptfskey=/etc/keys/ecryptfs-trusted.blob
1160 Deprecated, renamed Options
1161 ~~~~~~~~~~~~~~~~~~~~~~~~~~~
1162 Here is a list of options, which were used in dracut prior to version 008, and
1163 their new replacement.
1170 rd_DASD_MOD:: rd.dasd
1174 rdinitdebug rdnetdebug:: rd.debug
1178 rd_DM_UUID:: rd.dm.uuid
1180 rdblacklist:: rd.driver.blacklist
1182 rdinsmodpost:: rd.driver.post
1184 rdloaddriver:: rd.driver.pre
1186 rd_NO_FSTAB:: rd.fstab=0
1190 check:: rd.live.check
1192 rdlivedebug:: rd.live.debug
1194 live_dir:: rd.live.dir
1196 liveimg:: rd.live.image
1198 overlay:: rd.live.overlay
1200 readonly_overlay:: rd.live.overlay.readonly
1202 reset_overlay:: rd.live.overlay.reset
1204 live_ram:: rd.live.ram
1206 rd_NO_CRYPTTAB:: rd.luks.crypttab=0
1208 rd_LUKS_KEYDEV_UUID:: rd.luks.keydev.uuid
1210 rd_LUKS_KEYPATH:: rd.luks.keypath
1212 rd_NO_LUKS:: rd.luks=0
1214 rd_LUKS_UUID:: rd.luks.uuid
1216 rd_NO_LVMCONF:: rd.lvm.conf
1218 rd_LVM_LV:: rd.lvm.lv
1220 rd_NO_LVM:: rd.lvm=0
1222 rd_LVM_SNAPSHOT:: rd.lvm.snapshot
1224 rd_LVM_SNAPSIZE:: rd.lvm.snapsize
1226 rd_LVM_VG:: rd.lvm.vg
1228 rd_NO_MDADMCONF:: rd.md.conf=0
1230 rd_NO_MDIMSM:: rd.md.imsm=0
1234 rd_MD_UUID:: rd.md.uuid
1236 rd_NO_MULTIPATH: rd.multipath=0
1238 rd_NFS_DOMAIN:: rd.nfs.domain
1240 iscsi_initiator:: rd.iscsi.initiator
1242 iscsi_target_name:: rd.iscsi.target.name
1244 iscsi_target_ip:: rd.iscsi.target.ip
1246 iscsi_target_port:: rd.iscsi.target.port
1248 iscsi_target_group:: rd.iscsi.target.group
1250 iscsi_username:: rd.iscsi.username
1252 iscsi_password:: rd.iscsi.password
1254 iscsi_in_username:: rd.iscsi.in.username
1256 iscsi_in_password:: rd.iscsi.in.password
1258 iscsi_firmware:: rd.iscsi.firmware=0
1260 rd_NO_PLYMOUTH:: rd.plymouth=0
1266 rd_NO_SPLASH:: rd.splash
1268 rdudevdebug:: rd.udev.debug
1270 rdudevinfo:: rd.udev.info
1272 rd_NO_ZFCPCONF:: rd.zfcp.conf=0
1278 KEYMAP:: vconsole.keymap
1280 KEYTABLE:: vconsole.keymap
1282 SYSFONT:: vconsole.font
1284 CONTRANS:: vconsole.font.map
1286 UNIMAP:: vconsole.font.unimap
1288 UNICODE:: vconsole.unicode
1290 EXT_KEYMAP:: vconsole.keymap.ext
1292 Configuration in the Initramfs
1293 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1295 Any files found in _/etc/conf.d/_ will be sourced in the initramfs to
1296 set initial values. Command line options will override these values
1297 set in the configuration files.
1300 Can contain additional command line options. Deprecated, better use
1301 /etc/cmdline.d/*.conf.
1303 _/etc/cmdline.d/*.conf_::
1304 Can contain additional command line options.
1312 *dracut*(8) *dracut.conf*(5)