9 dracut.cmdline - dracut kernel command line options
13 The root device used by the kernel is specified in the boot configuration
14 file on the kernel command line, as always.
16 The traditional _root=/dev/sda1_ style device specification is allowed, but not
17 encouraged. The root device should better be identified by LABEL or UUID. If a
18 label is used, as in _root=LABEL=<label_of_root>_ the initramfs will search all
19 available devices for a filesystem with the appropriate label, and mount that
20 device as the root filesystem. _root=UUID=<uuidnumber>_ will mount the partition
21 with that UUID as the root filesystem.
23 In the following all kernel command line parameters, which are processed by
24 dracut, are described.
26 "rd.*" parameters mentioned without "=" are boolean parameters. They can be
27 turned on/off by setting them to {0|1}. If the assignment with "=" is missing
28 "=1" is implied. For example _rd.info_ can be turned off with _rd.info=0_ or
29 turned on with _rd.info=1_ or _rd.info_. The last value in the kernel command
30 line is the value, which is honored.
34 **init=**__<path to real init>__::
35 specify the path to the init program to be started after the initramfs has
38 **root=**__<path to blockdevice>__::
39 specify the block device to use as the root filesystem.
45 root=/dev/disk/by-path/pci-0000:00:1f.1-scsi-0:0:1:0-part1
46 root=/dev/disk/by-label/Root
48 root=/dev/disk/by-uuid/3f5ad593-4546-4a94-a374-bcfb68aa11f7
49 root=UUID=3f5ad593-4546-4a94-a374-bcfb68aa11f7
50 root=PARTUUID=3f5ad593-4546-4a94-a374-bcfb68aa11f7
53 **rootfstype=**__<filesystem type>__:: "auto" if not specified.
61 **rootflags=**__<mount options>__::
62 specify additional mount options for the root filesystem. If not set,
63 _/etc/fstab_ of the real root will be parsed for special mount options and
67 force mounting _/_ and _/usr_ (if it is a separate device) read-only. If
68 none of ro and rw is present, both are mounted according to _/etc/fstab_.
71 force mounting _/_ and _/usr_ (if it is a separate device) read-write.
74 **rootfallback=**__<path to blockdevice>__::
75 specify the block device to use as the root filesystem, if the normal root
76 cannot be found. This can only be a simple block device with a simple file
77 system, for which the filesystem driver is either compiled in, or added
78 manually to the initramfs. This parameter can be specified multiple times.
80 **rd.auto** **rd.auto=1**::
81 enable autoassembly of special devices like cryptoLUKS, dmraid, mdraid or
82 lvm. Default is off as of dracut version >= 024.
85 removes all compiled in configuration of the host system the initramfs image
86 was built on. This helps booting, if any disk layout changed, especially in
87 combination with rd.auto or other parameters specifying the layout.
90 prompts the user for additional kernel command line parameters
93 do not honor special mount options for the root filesystem found in
94 _/etc/fstab_ of the real root.
96 **resume=**__<path to resume partition>__::
97 resume from a swap partition
102 resume=/dev/disk/by-path/pci-0000:00:1f.1-scsi-0:0:1:0-part1
103 resume=/dev/disk/by-uuid/3f5ad593-4546-4a94-a374-bcfb68aa11f7
104 resume=UUID=3f5ad593-4546-4a94-a374-bcfb68aa11f7
108 skip fsck for rootfs and _/usr_. If you're mounting _/usr_ read-only and
109 the init system performs fsck before remount, you might want to use this
110 option to avoid duplication.
115 Using iso-scan/filename with a Fedora/Red Hat/CentOS Live iso should just work
116 by copying the original kernel cmdline parameters.
121 menuentry 'Live Fedora 20' --class fedora --class gnu-linux --class gnu --class os {
122 set isolabel=Fedora-Live-LXDE-x86_64-20-1
123 set isofile="/boot/iso/Fedora-Live-LXDE-x86_64-20-1.iso"
124 loopback loop $isofile
125 linux (loop)/isolinux/vmlinuz0 boot=isolinux iso-scan/filename=$isofile root=live:LABEL=$isolabel ro rd.live.image quiet rhgb
126 initrd (loop)/isolinux/initrd0.img
132 **rd.emergency=**__[reboot|poweroff|halt]__::
133 specify, what action to execute in case of a critical failure. rd.shell=0 also
136 **rd.driver.blacklist=**__<drivername>__[,__<drivername>__,...]::
137 do not load kernel module <drivername>. This parameter can be specified
140 **rd.driver.pre=**__<drivername>__[,__<drivername>__,...]::
141 force loading kernel module <drivername>. This parameter can be specified
144 **rd.driver.post=**__<drivername>__[,__<drivername>__,...]::
145 force loading kernel module <drivername> after all automatic loading modules
146 have been loaded. This parameter can be specified multiple times.
148 **rd.retry=**__<seconds>__::
149 specify how long dracut should retry the initqueue to configure devices.
150 The default is 30 seconds. After 2/3 of the time, degraded raids are force
151 started. If you have hardware, which takes a very long time to announce its
152 drives, you might want to extend this value.
154 **rd.timeout=**__<seconds>__::
155 specify how long dracut should wait for devices to appear. The
156 default is '0', which means 'forever'. Note that this timeout
157 should be longer than rd.retry to allow for proper configuration.
160 accept self-signed certificates for ssl downloads.
162 **rd.ctty=**__<terminal device>__::
163 specify the controlling terminal for the console.
164 This is useful, if you have multiple "console=" arguments.
166 [[dracutkerneldebug]]
169 If you are dropped to an emergency shell, the file
170 _/run/initramfs/rdsosreport.txt_ is created, which can be saved to a (to be
171 mounted by hand) partition (usually /boot) or a USB stick. Additional debugging
172 info can be produced by adding **rd.debug** to the kernel command line.
173 _/run/initramfs/rdsosreport.txt_ contains all logs and the output of some tools.
174 It should be attached to any report about dracut problems.
177 print informational output though "quiet" is set
180 allow dropping to a shell, if root mounting fails
183 set -x for the dracut shell.
184 If systemd is active in the initramfs, all output is logged to the systemd
185 journal, which you can inspect with "journalctl -ab".
186 If systemd is not active, the logs are written to dmesg and
187 _/run/initramfs/init.log_.
188 If "quiet" is set, it also logs to the console.
190 **rd.memdebug=[0-4]**::
191 Print memory usage info at various points, set the verbose level from 0 to 4.
193 Higher level means more debugging output:
197 1 - partial /proc/meminfo
199 3 - /proc/meminfo + /proc/slabinfo
200 4 - /proc/meminfo + /proc/slabinfo + tracekomem
201 NOTE: tracekomem is a shell script utilizing kernel trace to track
202 the rough total memory consumption of kernel modules during
203 loading. It may override other trace configurations.
207 drop to a shell at the end
209 **rd.break=**__{cmdline|pre-udev|pre-trigger|initqueue|pre-mount|mount|pre-pivot|cleanup}__::
210 drop to a shell on defined breakpoint
213 set udev to loglevel info
216 set udev to loglevel debug
220 **rd.vconsole.keymap=**__<keymap base file name>__::
221 keyboard translation table loaded by loadkeys; taken from keymaps directory;
222 will be written as KEYMAP to _/etc/vconsole.conf_ in the initramfs.
227 rd.vconsole.keymap=de-latin1-nodeadkeys
230 **rd.vconsole.keymap.ext=**__<list of keymap base file names>__::
231 list of extra keymaps to bo loaded (sep. by space); will be written as
232 EXT_KEYMAP to _/etc/vconsole.conf_ in the initramfs
234 **rd.vconsole.unicode**::
235 boolean, indicating UTF-8 mode; will be written as UNICODE to
236 _/etc/vconsole.conf_ in the initramfs
238 **rd.vconsole.font=**__<font base file name>__::
239 console font; taken from consolefonts directory; will be written as FONT to
240 _/etc/vconsole.conf_ in the initramfs.
245 rd.vconsole.font=LatArCyrHeb-16
248 **rd.vconsole.font.map=**__<console map base file name>__::
249 see description of '-m' parameter in setfont manual; taken from consoletrans
250 directory; will be written as FONT_MAP to _/etc/vconsole.conf_ in the
253 **rd.vconsole.font.unimap=**__<unicode table base file name>__::
254 see description of '-u' parameter in setfont manual; taken from unimaps
255 directory; will be written as FONT_UNIMAP to _/etc/vconsole.conf_ in the
258 **rd.locale.LANG=**__<locale>__::
259 taken from the environment; if no UNICODE is defined we set its value in
260 basis of LANG value (whether it ends with ".utf8" (or similar) or not); will
261 be written as LANG to _/etc/locale.conf_ in the initramfs.
266 rd.locale.LANG=pl_PL.utf8
269 **rd.locale.LC_ALL=**__<locale>__::
270 taken from the environment; will be written as LC_ALL to _/etc/locale.conf_
276 disable LVM detection
278 **rd.lvm.vg=**__<volume group name>__::
279 only activate the volume groups with the given name. rd.lvm.vg can be
280 specified multiple times on the kernel command line.
282 **rd.lvm.lv=**__<logical volume name>__::
283 only activate the logical volumes with the given name. rd.lvm.lv can be
284 specified multiple times on the kernel command line.
287 remove any _/etc/lvm/lvm.conf_, which may exist in the initramfs
292 disable crypto LUKS detection
294 **rd.luks.uuid=**__<luks uuid>__::
295 only activate the LUKS partitions with the given UUID. Any "luks-" of the
296 LUKS UUID is removed before comparing to _<luks uuid>_.
297 The comparisons also matches, if _<luks uuid>_ is only the beginning of the
298 LUKS UUID, so you don't have to specify the full UUID.
299 This parameter can be specified multiple times.
301 **rd.luks.allow-discards=**__<luks uuid>__::
302 Allow using of discards (TRIM) requests for LUKS partitions with the given
303 UUID. Any "luks-" of the LUKS UUID is removed before comparing to
304 _<luks uuid>_. The comparisons also matches, if _<luks uuid>_ is only the
305 beginning of the LUKS UUID, so you don't have to specify the full UUID.
306 This parameter can be specified multiple times.
308 **rd.luks.allow-discards**::
309 Allow using of discards (TRIM) requests on all LUKS partitions.
311 **rd.luks.crypttab=0**::
312 do not check, if LUKS partition is in _/etc/crypttab_
314 crypto LUKS - key on removable device support
315 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
316 **rd.luks.key=**__<keypath>__:__<keydev>__:__<luksdev>__::
317 _keypath_ is a path to key file to look for. It's REQUIRED. When _keypath_
318 ends with '.gpg' it's considered to be key encrypted symmetrically with GPG.
319 You will be prompted for password on boot. GPG support comes with
320 'crypt-gpg' module which needs to be added explicitly.
322 _keydev_ is a device on which key file resides. It might be kernel name of
323 devices (should start with "/dev/"), UUID (prefixed with "UUID=") or label
324 (prefix with "LABEL="). You don't have to specify full UUID. Just its beginning
325 will suffice, even if its ambiguous. All matching devices will be probed.
326 This parameter is recommended, but not required. If not present, all block
327 devices will be probed, which may significantly increase boot time.
329 If _luksdev_ is given, the specified key will only be applied for that LUKS
330 device. Possible values are the same as for _keydev_. Unless you have several
331 LUKS devices, you don't have to specify this parameter. The simplest usage is:
336 rd.luks.key=/foo/bar.key
339 As you see, you can skip colons in such a case.
342 ===============================
343 dracut pipes key to cryptsetup with _-d -_ argument, therefore you need to pipe
344 to crypsetup luksFormat with _-d -_, too!
346 Here follows example for key encrypted with GPG:
350 gpg --quiet --decrypt rootkey.gpg | \
351 cryptsetup -d - -v --cipher serpent-cbc-essiv:sha256 \
352 --key-size 256 luksFormat /dev/sda3
355 If you use plain keys, just add path to _-d_ option:
359 cryptsetup -d rootkey.key -v --cipher serpent-cbc-essiv:sha256 \
360 --key-size 256 luksFormat /dev/sda3
362 ===============================
367 disable MD RAID detection
370 disable MD RAID for imsm/isw raids, use DM RAID instead
373 disable MD RAID for SNIA ddf raids, use DM RAID instead
376 ignore mdadm.conf included in initramfs
378 **rd.md.waitclean=1**::
379 wait for any resync, recovery, or reshape activity to finish before
382 **rd.md.uuid=**__<md raid uuid>__::
383 only activate the raid sets with the given UUID. This parameter can be
384 specified multiple times.
389 disable DM RAID detection
391 **rd.dm.uuid=**__<dm raid uuid>__::
392 only activate the raid sets with the given UUID. This parameter can be
393 specified multiple times.
398 disable multipath detection
405 **boot=**__<boot device>__::
406 specify the device, where /boot is located.
412 boot=/dev/disk/by-path/pci-0000:00:1f.1-scsi-0:0:1:0-part1
417 **rd.fips.skipkernel**::
418 skip checksum check of the kernel image. Useful, if the kernel image is not
419 in a separate boot partition.
425 =====================
426 It is recommended to either bind an interface to a MAC with the **ifname**
427 argument, or to use the systemd-udevd predictable network interface names.
429 Predictable network interface device names based on:
431 - firmware/bios-provided index numbers for on-board devices
432 - firmware-provided pci-express hotplug slot index number
433 - physical/geographical location of the hardware
434 - the interface's MAC address
437 http://www.freedesktop.org/wiki/Software/systemd/PredictableNetworkInterfaceNames
439 Two character prefixes based on the type of interface:
447 o<index>:: on-board device index number
448 s<slot>[f<function>][d<dev_id>]:: hotplug slot index number
450 [P<domain>]p<bus>s<slot>[f<function>][d<dev_id>]:: PCI geographical location
451 [P<domain>]p<bus>s<slot>[f<function>][u<port>][..][c<config>][i<interface>]:: USB port number chain
453 All multi-function PCI devices will carry the [f<function>] number in the
454 device name, including the function 0 device.
456 When using PCI geography, The PCI domain is only prepended when it is not 0.
458 For USB devices the full chain of port numbers of hubs is composed. If the
459 name gets longer than the maximum number of 15 characters, the name is not
461 The usual USB configuration == 1 and interface == 0 values are suppressed.
463 PCI ethernet card with firmware index "1"::
466 PCI ethernet card in hotplug slot with firmware index number::
469 PCI ethernet multi-function card with 2 ports::
476 USB built-in 3G modem::
481 =====================
483 **ip=**__{dhcp|on|any|dhcp6|auto6|either6}__::
484 dhcp|on|any::: get ip from dhcp server from all interfaces. If root=dhcp,
485 loop sequentially through all interfaces (eth0, eth1, ...) and use the first
486 with a valid DHCP root-path.
488 auto6::: IPv6 autoconfiguration
492 either6::: if auto6 fails, then dhcp6
494 **ip=**__<interface>__:__{dhcp|on|any|dhcp6|auto6}__[:[__<mtu>__][:__<macaddr>__]]::
495 This parameter can be specified multiple times.
497 =====================
498 dhcp|on|any|dhcp6::: get ip from dhcp server on a specific interface
499 auto6::: do IPv6 autoconfiguration
500 <macaddr>::: optionally **set** <macaddr> on the <interface>. This
501 cannot be used in conjunction with the **ifname** argument for the
503 =====================
505 **ip=**__<client-IP>__:[__<peer>__]:__<gateway-IP>__:__<netmask>__:__<client_hostname>__:__<interface>__:__{none|off|dhcp|on|any|dhcp6|auto6|ibft}__[:[__<mtu>__][:__<macaddr>__]]::
506 explicit network configuration. If you want do define a IPv6 address, put it
507 in brackets (e.g. [2001:DB8::1]). This parameter can be specified multiple
508 times. __<peer>__ is optional and is the address of the remote endpoint
509 for pointopoint interfaces and it may be followed by a slash and a decimal
510 number, encoding the network prefix length.
512 =====================
513 <macaddr>::: optionally **set** <macaddr> on the <interface>. This
514 cannot be used in conjunction with the **ifname** argument for the
516 =====================
518 **ip=**__<client-IP>__:[__<peer>__]:__<gateway-IP>__:__<netmask>__:__<client_hostname>__:__<interface>__:__{none|off|dhcp|on|any|dhcp6|auto6|ibft}__[:[__<dns1>__][:__<dns2>__]]::
519 explicit network configuration. If you want do define a IPv6 address, put it
520 in brackets (e.g. [2001:DB8::1]). This parameter can be specified multiple
521 times. __<peer>__ is optional and is the address of the remote endpoint
522 for pointopoint interfaces and it may be followed by a slash and a decimal
523 number, encoding the network prefix length.
525 **ifname=**__<interface>__:__<MAC>__::
526 Assign network device name <interface> (ie "bootnet") to the NIC with
529 WARNING: Do **not** use the default kernel naming scheme for the interface name,
530 as it can conflict with the kernel names. So, don't use "eth[0-9]+" for the
531 interface name. Better name it "bootnet" or "bluesocket".
533 **rd.route=**__<net>__/__<netmask>__:__<gateway>__[:__<interface>__]::
534 Add a static route with route options, which are separated by a colon.
535 IPv6 addresses have to be put in brackets.
540 rd.route=192.168.200.0/24:192.168.100.222:ens10
541 rd.route=192.168.200.0/24:192.168.100.222
542 rd.route=192.168.200.0/24::ens10
543 rd.route=[2001:DB8:3::/8]:[2001:DB8:2::1]:ens10
546 **bootdev=**__<interface>__::
547 specify network interface to use routing and netroot information from.
548 Required if multiple ip= lines are used.
550 **BOOTIF=**__<MAC>__::
551 specify network interface to use routing and netroot information from.
554 Disable BOOTIF parsing, which is provided by PXE
556 **nameserver=**__<IP>__ [**nameserver=**__<IP>__ ...]::
557 specify nameserver(s) to use
560 Disable DNS setting of DHCP parameters.
563 boolean, turn off biosdevname network interface renaming
566 boolean, bring up network even without netroot set
568 **vlan=**__<vlanname>__:__<phydevice>__::
569 Setup vlan device named <vlanname> on <phydeivce>.
570 We support the four styles of vlan names: VLAN_PLUS_VID (vlan0005),
571 VLAN_PLUS_VID_NO_PAD (vlan5), DEV_PLUS_VID (eth0.0005),
572 DEV_PLUS_VID_NO_PAD (eth0.5)
574 **bond=**__<bondname>__[:__<bondslaves>__:[:__<options>__[:<mtu>]]]::
575 Setup bonding device <bondname> on top of <bondslaves>.
576 <bondslaves> is a comma-separated list of physical (ethernet) interfaces.
577 <options> is a comma-separated list on bonding options (modinfo bonding for
578 details) in format compatible with initscripts. If <options> includes
579 multi-valued arp_ip_target option, then its values should be separated by
580 semicolon. if the mtu is specified, it will be set on the bond master.
581 Bond without parameters assumes
582 bond=bond0:eth0,eth1:mode=balance-rr
584 **team=**__<teammaster>__:__<teamslaves>__::
585 Setup team device <teammaster> on top of <teamslaves>.
586 <teamslaves> is a comma-separated list of physical (ethernet) interfaces.
588 **bridge=**__<bridgename>__:__<ethnames>__::
589 Setup bridge <bridgename> with <ethnames>. <ethnames> is a comma-separated
590 list of physical (ethernet) interfaces. Bridge without parameters assumes
595 **root=**\[_<server-ip>_:]__<root-dir>__[:__<nfs-options>__]::
596 mount nfs share from <server-ip>:/<root-dir>, if no server-ip is given, use
597 dhcp next_server. If server-ip is an IPv6 address it has to be put in
598 brackets, e.g. [2001:DB8::1]. NFS options can be appended with the prefix
599 ":" or "," and are seperated by ",".
601 **root=**nfs:\[_<server-ip>_:]__<root-dir>__[:__<nfs-options>__], **root=**nfs4:\[_<server-ip>_:]__<root-dir>__[:__<nfs-options>__], **root=**__{dhcp|dhcp6}__::
602 root=dhcp alone directs initrd to look at the DHCP root-path where NFS
603 options can be specified.
608 root-path=<server-ip>:<root-dir>[,<nfs-options>]
609 root-path=nfs:<server-ip>:<root-dir>[,<nfs-options>]
610 root-path=nfs4:<server-ip>:<root-dir>[,<nfs-options>]
613 **root=**_/dev/nfs_ nfsroot=\[_<server-ip>_:]__<root-dir>__[:__<nfs-options>__]::
614 _Deprecated!_ kernel Documentation_/filesystems/nfsroot.txt_ defines this
615 method. This is supported by dracut, but not recommended.
617 **rd.nfs.domain=**__<NFSv4 domain name>__::
618 Set the NFSv4 domain name. Will override the settings in _/etc/idmap.conf_.
620 **rd.net.dhcp.retry=**__<cnt>__::
621 If this option is set, dracut will try to connect via dhcp <cnt> times before failing.
624 **rd.net.timeout.dhcp=**__<arg>__::
625 If this option is set, dhclient is called with "-timeout <arg>".
627 **rd.net.timeout.iflink=**__<seconds>__::
628 Wait <seconds> until link shows up. Default is 60 seconds.
630 **rd.net.timeout.ifup=**__<seconds>__::
631 Wait <seconds> until link has state "UP". Default is 20 seconds.
633 **rd.net.timeout.route=**__<seconds>__::
634 Wait <seconds> until route shows up. Default is 20 seconds.
636 **rd.net.timeout.ipv6dad=**__<seconds>__::
637 Wait <seconds> until IPv6 DAD is finished. Default is 50 seconds.
639 **rd.net.timeout.ipv6auto=**__<seconds>__::
640 Wait <seconds> until IPv6 automatic addresses are assigned. Default is 40 seconds.
642 **rd.net.timeout.carrier=**__<seconds>__::
643 Wait <seconds> until carrier is recognized. Default is 5 seconds.
647 **root=**cifs://[__<username>__[:__<password>__]@]__<server-ip>__:__<root-dir>__::
648 mount cifs share from <server-ip>:/<root-dir>, if no server-ip is given, use
649 dhcp next_server. if server-ip is an IPv6 address it has to be put in
650 brackets, e.g. [2001:DB8::1]. If a username or password are not specified
651 as part of the root, then they must be passed on the command line through
654 WARNING: Passwords specified on the kernel command line are visible for all
655 users via the file _/proc/cmdline_ and via dmesg or can be sniffed on the
656 network, when using DHCP with DHCP root-path.
658 **cifsuser**=__<username>__::
659 Set the cifs username, if not specified as part of the root.
661 **cifspass**=__<password>__::
662 Set the cifs password, if not specified as part of the root.
664 WARNING: Passwords specified on the kernel command line are visible for all
665 users via the file _/proc/cmdline_ and via dmesg or can be sniffed on the
666 network, when using DHCP with DHCP root-path.
670 **root=**iscsi:[__<username>__:__<password>__[:__<reverse>__:__<password>__]@][__<servername>__]:[__<protocol>__]:[__<port>__][:[__<iscsi_iface_name>__]:[__<netdev_name>__]]:[__<LUN>__]:__<targetname>__::
671 protocol defaults to "6", LUN defaults to "0". If the "servername" field is
672 provided by BOOTP or DHCP, then that field is used in conjunction with other
673 associated fields to contact the boot server in the Boot stage. However, if
674 the "servername" field is not provided, then the "targetname" field is then
675 used in the Discovery Service stage in conjunction with other associated
677 link:$$http://tools.ietf.org/html/rfc4173#section-5$$[rfc4173].
679 WARNING: Passwords specified on the kernel command line are visible for all
680 users via the file _/proc/cmdline_ and via dmesg or can be sniffed on the
681 network, when using DHCP with DHCP root-path.
686 root=iscsi:192.168.50.1::::iqn.2009-06.dracut:target0
689 If servername is an IPv6 address, it has to be put in brackets:
694 root=iscsi:[2001:DB8::1]::::iqn.2009-06.dracut:target0
697 **root=**__???__ **netroot=**iscsi:[__<username>__:__<password>__[:__<reverse>__:__<password>__]@][__<servername>__]:[__<protocol>__]:[__<port>__][:[__<iscsi_iface_name>__]:[__<netdev_name>__]]:[__<LUN>__]:__<targetname>__ ...::
698 multiple netroot options allow setting up multiple iscsi disks:
704 netroot=iscsi:192.168.50.1::::iqn.2009-06.dracut:target0
705 netroot=iscsi:192.168.50.1::::iqn.2009-06.dracut:target1
708 If servername is an IPv6 address, it has to be put in brackets:
713 netroot=iscsi:[2001:DB8::1]::::iqn.2009-06.dracut:target0
716 WARNING: Passwords specified on the kernel command line are visible for all
717 users via the file _/proc/cmdline_ and via dmesg or can be sniffed on the
718 network, when using DHCP with DHCP root-path.
719 You may want to use rd.iscsi.firmware.
721 **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>__::
722 manually specify all iscsistart parameter (see **+iscsistart --help+**)
724 WARNING: Passwords specified on the kernel command line are visible for all
725 users via the file _/proc/cmdline_ and via dmesg or can be sniffed on the
726 network, when using DHCP with DHCP root-path.
727 You may want to use rd.iscsi.firmware.
729 **root=**_???_ **netroot=**iscsi **rd.iscsi.firmware=1**::
730 will read the iscsi parameter from the BIOS firmware
732 **rd.iscsi.param=**__<param>__::
733 <param> will be passed as "--param <param>" to iscsistart.
734 This parameter can be specified multiple times.
739 "netroot=iscsi rd.iscsi.firmware=1 rd.iscsi.param=node.session.timeo.replacement_timeout=30"
746 iscsistart -b --param node.session.timeo.replacement_timeout=30
749 **rd.iscsi.ibft** **rd.iscsi.ibft=1**:
750 Turn on iBFT autoconfiguration for the interfaces
752 **rd.iscsi.waitnet=0**:
753 Turn off waiting for all interfaces to be up before trying to login to the iSCSI targets.
755 **rd.iscsi.testroute=0**:
756 Turn off checking, if the route to the iSCSI target IP is possible before trying to login.
760 **fcoe=**__<edd|interface|MAC>__:__{dcb|nodcb}__:__{fabric|vn2vn}__::
761 Try to connect to a FCoE SAN through the NIC specified by _<interface>_ or
762 _<MAC>_ or EDD settings. The second argument specifies if DCB
763 should be used. The optional third argument specifies whether
764 fabric or VN2VN mode should be used.
765 This parameter can be specified multiple times.
767 NOTE: letters in the MAC-address must be lowercase!
771 **root=**??? **netroot=**nbd:__<server>__:__<port/exportname>__[:__<fstype>__[:__<mountopts>__[:__<nbdopts>__]]]::
772 mount nbd share from <server>.
775 If "exportname" instead of "port" is given the standard port is used.
776 Newer versions of nbd are only supported with "exportname".
778 **root=dhcp** with **dhcp** **root-path=**nbd:__<server>__:__<port/exportname>__[:__<fstype>__[:__<mountopts>__[:__<nbdopts>__]]]::
779 root=dhcp alone directs initrd to look at the DHCP root-path where NBD
780 options can be specified. This syntax is only usable in cases where you are
781 directly mounting the volume as the rootfs.
784 If "exportname" instead of "port" is given the standard port is used.
785 Newer versions of nbd are only supported with "exportname".
790 same syntax as the kernel module parameter (s390 only)
794 **rd.zfcp=**__<zfcp adaptor device bus ID>__,__<WWPN>__,__<FCPLUN>__::
795 rd.zfcp can be specified multiple times on the kernel command
798 **rd.zfcp=**__<zfcp adaptor device bus ID>__::
799 If NPIV is enabled and the 'allow_lun_scan' parameter to the zfcp
800 module is set to 'Y' then the zfcp adaptor will be initiating a
801 scan internally and the <WWPN> and <FCPLUN> parameters can be omitted.
806 rd.zfcp=0.0.4000,0x5005076300C213e9,0x5022000000000000
811 ignore zfcp.conf included in the initramfs
815 **rd.znet=**__<nettype>__,__<subchannels>__,__<options>__::
816 The whole parameter is appended to /etc/ccw.conf, which is used on
817 RHEL/Fedora with ccw_init, which is called from udev for certain
819 rd.znet can be specified multiple times on the kernel command line.
824 rd.znet=qeth,0.0.0600,0.0.0601,0.0.0602,layer2=1,portname=foo
825 rd.znet=ctc,0.0.0600,0.0.0601,protocol=bar
830 Dracut offers multiple options for live booted images:
832 =====================
833 SquashFS with read-only filesystem image::: The system will boot with a read
834 only filesystem from the SquashFS and apply a writable device-mapper snapshot
835 over the read only filesystem. Using this method ensures a relatively fast
836 boot and lower RAM usage. Users **must be careful** to avoid writing too many
837 blocks to the snapshot volume. Once the blocks of the snapshot overlay are
838 exhausted, the root filesystem becomes read only and may cause application
839 failures. The overlay file is marked 'Overflow', and a difficult recovery is
840 required to repair and enlarge the overlay offline. Non-persistent overlays
841 are sparse files in RAM that only consume content space as required blocks are
842 allocated. They default to an apparent size of 32 GiB in RAM. The size can be
843 adjusted with the **rd.live.overlay.size=** kernel command line option.
845 The filesystem structure is expected to be:
849 squashfs.img | Squashfs from LiveCD .iso downloaded via network
852 |- rootfs.img | Filesystem image to mount read-only
854 /bin | Live filesystem
860 Dracut uses this method of live booting by default. No additional command line
861 options are required other than **root=live:<URL>** to specify the location
862 of your squashed filesystem.
864 - The compressed SquashFS image can be copied during boot to RAM at
865 `/run/initramfs/squashed.img` by using the **rd.live.ram=1** option.
866 - A device with a persistent overlay can be booted read only by using the
867 **rd.live.overlay.readonly** option on the kernel command line. This will
868 cause a temporary, writable overlay to be stacked over a read-only snapshot
869 of the root filesystem.
871 Uncompressed live filesystem image:::
872 When the live system was installed with the '--skipcompress' option of the
873 __livecd-iso-to-disk__ installation script for Live USB devices, the root
874 filesystem image, `rootfs.img`, is expanded on installation and no SquashFS
875 is involved during boot.
877 - If **rd.live.ram=1** is used in this situation, the full, uncompressed
878 root filesystem is copied during boot to `/run/initramfs/rootfs.img` in the
881 - If **rd.live.overlay=none** is provided as a kernel command line option,
882 a writable, linear device-mapper target is created on boot with no overlay.
884 writable filesystem image:::
885 The system will retrieve a compressed filesystem image, extract it to
886 `/run/initramfs/fsimg/rootfs.img`, connect it to a loop device, create a
887 writable, linear device-mapper target at `/dev/mapper/live-rw`, and mount that
888 as a writable volume at `/`. More RAM is required during boot but the live
889 filesystem is easier to manage if it becomes full. Users can make a filesystem
890 image of any size and that size will be maintained when the system boots. There
891 is no persistence of root filesystem changes between boots with this option.
893 The filesystem structure is expected to be:
897 rootfs.tgz | Compressed tarball containing fileystem image
899 /rootfs.img | Filesystem image at /run/initramfs/fsimg/
901 /bin | Live filesystem
907 To use this boot option, ensure that **rd.writable.fsimg=1** is in your kernel
908 command line and add the **root=live:<URL>** to specify the location
909 of your compressed filesystem image tarball or SquashFS image.
910 =====================
912 **rd.writable.fsimg=**1::
913 Enables writable filesystem support. The system will boot with a fully
914 writable (but non-persistent) filesystem without snapshots __(see notes above
915 about available live boot options)__. You can use the **rootflags** option to
916 set mount options for the live filesystem as well __(see documentation about
917 rootflags in the **Standard** section above)__.
918 This implies that the whole image is copied to RAM before the boot continues.
920 NOTE: There must be enough free RAM available to hold the complete image.
922 This method is very suitable for diskless boots.
924 **root=**live:__<url>__::
925 Boots a live image retrieved from __<url>__. Valid handlers: __http, https, ftp, torrent, tftp__.
930 root=live:http://example.com/liveboot.img
931 root=live:ftp://ftp.example.com/liveboot.img
932 root=live:torrent://example.com/liveboot.img.torrent
935 **rd.live.debug=**1::
936 Enables debug output from the live boot process.
938 **rd.live.dir=**__<path>__::
939 Specifies the directory within the boot device where the squashfs.img or
940 rootfs.img can be found. By default, this is __LiveOS__.
942 **rd.live.squashimg=**__<filename of SquashFS image>__::
943 Specifies the filename for a SquashFS image of the root filesystem.
944 By default, this is __squashfs.img__.
947 Copy the complete image to RAM and use this for booting. This is useful
948 when the image resides on, i.e., a DVD which needs to be ejected later on.
950 **rd.live.overlay=**__<devspec>__:__(<pathspec>|auto)__|__none__::
951 Allow the usage of a permanent overlay.
952 - _<devspec>_ specifies the path to a device with a mountable filesystem.
953 - _<pathspec>_ is the path to a file within that filesystem, which shall be
954 used to persist the changes made to the device specified by the
955 **root=live:__<url>__** option.
956 - _none_ specifies no overlay when an uncompressed live root filesystem is
958 If a persistent overlay is detected at the standard LiveOS path, the overlay &
959 overlay type detected (whether Device-mapper or OverlayFS) will be used.
964 rd.live.overlay=/dev/sdb1:persistent-overlay.img
967 **rd.live.overlay.size=**__<size_MiB>__::
968 Specifies a non-persistent overlay size in MiB. The default is _32768_.
970 **rd.live.overlay.readonly=**1::
971 Specifies a non-persistent, writable snapshot overlay to be stacked over a
972 read-only snapshot of the root filesystem, `/dev/mapper/live-ro`, or a read-
973 only loop device of a writable `rootfs.img`.
975 **rd.live.overlay.reset=**1::
976 Specifies that a persistent overlay should be reset on boot. All root
977 filesystem changes are vacated by this action.
979 **rd.live.overlay.thin=**1::
980 Enables the usage of thin snapshots instead of classic dm snapshots.
981 The advantage of thin snapshots is that they support discards, and will free
982 blocks that are not claimed by the filesystem. In this use case, this means
983 that memory is given back to the kernel when the filesystem does not claim it
986 **rd.live.overlay.overlayfs=**1::
987 Enables the use of the **OverlayFS** kernel module, if available, to provide a
988 copy-on-write union directory for the root filesystem. OverlayFS overlays are
989 directories of the files that have changed on the read-only base (lower)
990 filesystem. The root filesystem is provided through a special overlay type
991 mount that merges the lower and upper directories. If an OverlayFS upper
992 directory is not present on the boot device, a tmpfs directory will be created
993 at /run/overlayfs to provide temporary storage. Persistent storage can be
994 provided on vfat or msdos formatted devices by supplying the OverlayFS upper
995 directory within an embedded filesystem that supports the creation of trusted.*
996 extended attributes and provides a valid d_type in readdir responses, such as
997 with ext4 and xfs. On non-vfat-formatted devices, a persistent OverlayFS
998 overlay can extend the available root filesystem storage up to the capacity of
1001 If a persistent overlay is detected at the standard LiveOS path, the overlay &
1002 overlay type detected (whether OverlayFS or Device-mapper) will be used.
1004 The **rd.live.overlay.readonly** option, which allows a persistent overlayfs to
1005 be mounted read only through a higher level transient overlay directory, has
1006 been implemented through the multiple lower layers feature of OverlayFS.
1011 **rd.zipl=**__<path to blockdevice>__::
1012 Update the dracut commandline with the values found in the
1013 _dracut-cmdline.conf_ file on the given device.
1014 The values are merged into the existing commandline values
1015 and the udev events are regenerated.
1020 rd.zipl=UUID=0fb28157-99e3-4395-adef-da3f7d44835a
1025 **rd.cio_accept=**__<device-ids>__::
1026 Remove the devices listed in <device-ids> from the default
1027 cio_ignore kernel command-line settings.
1028 <device-ids> is a list of comma-separated CCW device ids.
1029 The default for this value is taken from the
1030 _/boot/zipl/active_devices.txt_ file.
1035 rd.cio_accept=0.0.0180,0.0.0800,0.0.0801,0.0.0802
1038 Plymouth Boot Splash
1039 ~~~~~~~~~~~~~~~~~~~~
1040 **plymouth.enable=0**::
1041 disable the plymouth bootsplash completely.
1044 disable the plymouth bootsplash only for the initramfs.
1048 **masterkey=**__<kernel master key path name>__::
1049 Set the path name of the kernel master key.
1054 masterkey=/etc/keys/kmk-trusted.blob
1057 **masterkeytype=**__<kernel master key type>__::
1058 Set the type of the kernel master key.
1063 masterkeytype=trusted
1066 **evmkey=**__<EVM key path name>__::
1067 Set the path name of the EVM key.
1072 evmkey=/etc/keys/evm-trusted.blob
1075 **ecryptfskey=**__<eCryptfs key path name>__::
1076 Set the path name of the eCryptfs key.
1081 ecryptfskey=/etc/keys/ecryptfs-trusted.blob
1084 Deprecated, renamed Options
1085 ~~~~~~~~~~~~~~~~~~~~~~~~~~~
1086 Here is a list of options, which were used in dracut prior to version 008, and
1087 their new replacement.
1094 rd_DASD_MOD:: rd.dasd
1098 rdinitdebug rdnetdebug:: rd.debug
1102 rd_DM_UUID:: rd.dm.uuid
1104 rdblacklist:: rd.driver.blacklist
1106 rdinsmodpost:: rd.driver.post
1108 rdloaddriver:: rd.driver.pre
1110 rd_NO_FSTAB:: rd.fstab=0
1114 check:: rd.live.check
1116 rdlivedebug:: rd.live.debug
1118 live_dir:: rd.live.dir
1120 liveimg:: rd.live.image
1122 overlay:: rd.live.overlay
1124 readonly_overlay:: rd.live.overlay.readonly
1126 reset_overlay:: rd.live.overlay.reset
1128 live_ram:: rd.live.ram
1130 rd_NO_CRYPTTAB:: rd.luks.crypttab=0
1132 rd_LUKS_KEYDEV_UUID:: rd.luks.keydev.uuid
1134 rd_LUKS_KEYPATH:: rd.luks.keypath
1136 rd_NO_LUKS:: rd.luks=0
1138 rd_LUKS_UUID:: rd.luks.uuid
1140 rd_NO_LVMCONF:: rd.lvm.conf
1142 rd_LVM_LV:: rd.lvm.lv
1144 rd_NO_LVM:: rd.lvm=0
1146 rd_LVM_SNAPSHOT:: rd.lvm.snapshot
1148 rd_LVM_SNAPSIZE:: rd.lvm.snapsize
1150 rd_LVM_VG:: rd.lvm.vg
1152 rd_NO_MDADMCONF:: rd.md.conf=0
1154 rd_NO_MDIMSM:: rd.md.imsm=0
1158 rd_MD_UUID:: rd.md.uuid
1160 rd_NO_MULTIPATH: rd.multipath=0
1162 rd_NFS_DOMAIN:: rd.nfs.domain
1164 iscsi_initiator:: rd.iscsi.initiator
1166 iscsi_target_name:: rd.iscsi.target.name
1168 iscsi_target_ip:: rd.iscsi.target.ip
1170 iscsi_target_port:: rd.iscsi.target.port
1172 iscsi_target_group:: rd.iscsi.target.group
1174 iscsi_username:: rd.iscsi.username
1176 iscsi_password:: rd.iscsi.password
1178 iscsi_in_username:: rd.iscsi.in.username
1180 iscsi_in_password:: rd.iscsi.in.password
1182 iscsi_firmware:: rd.iscsi.firmware=0
1184 rd_NO_PLYMOUTH:: rd.plymouth=0
1190 rd_NO_SPLASH:: rd.splash
1192 rdudevdebug:: rd.udev.debug
1194 rdudevinfo:: rd.udev.info
1196 rd_NO_ZFCPCONF:: rd.zfcp.conf=0
1202 KEYMAP:: vconsole.keymap
1204 KEYTABLE:: vconsole.keymap
1206 SYSFONT:: vconsole.font
1208 CONTRANS:: vconsole.font.map
1210 UNIMAP:: vconsole.font.unimap
1212 UNICODE:: vconsole.unicode
1214 EXT_KEYMAP:: vconsole.keymap.ext
1216 Configuration in the Initramfs
1217 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1219 Any files found in _/etc/conf.d/_ will be sourced in the initramfs to
1220 set initial values. Command line options will override these values
1221 set in the configuration files.
1224 Can contain additional command line options. Deprecated, better use
1225 /etc/cmdline.d/*.conf.
1227 _/etc/cmdline.d/*.conf_::
1228 Can contain additional command line options.
1236 *dracut*(8) *dracut.conf*(5)