1DRACUT.CMDLINE(7) dracut DRACUT.CMDLINE(7)
2
6 dracut.cmdline - dracut kernel command line options
7
9 The root device used by the kernel is specified in the boot
10 configuration file on the kernel command line, as always.
11 The traditional root=/dev/sda1 style device specification is allowed,
13 but not encouraged. The root device should better be identified by
14 LABEL or UUID. If a label is used, as in root=LABEL=<label_of_root> the
15 initramfs will search all available devices for a filesystem with the
16 appropriate label, and mount that device as the root filesystem.
17 root=UUID=<uuidnumber> will mount the partition with that UUID as the
18 root filesystem.
19 In the following all kernel command line parameters, which are
21 processed by dracut, are described.
22 "rd.*" parameters mentioned without "=" are boolean parameters. They
24 can be turned on/off by setting them to {0|1}. If the assignment with
25 "=" is missing "=1" is implied. For example rd.info can be turned off
26 with rd.info=0 or turned on with rd.info=1 or rd.info. The last value
27 in the kernel command line is the value, which is honored.
28 Standard
30 init=<path to real init>
31 specify the path to the init programm to be started after the
32 initramfs has finished
33 root=<path to blockdevice>
35 specify the block device to use as the root filesystem.
36 Example.
38 root=/dev/sda1
40 root=/dev/disk/by-path/pci-0000:00:1f.1-scsi-0:0:1:0-part1
41 root=/dev/disk/by-label/Root
42 root=LABEL=Root
43 root=/dev/disk/by-uuid/3f5ad593-4546-4a94-a374-bcfb68aa11f7
44 root=UUID=3f5ad593-4546-4a94-a374-bcfb68aa11f7
45 root=PARTUUID=3f5ad593-4546-4a94-a374-bcfb68aa11f7
46 rootfstype=<filesystem type>
49 "auto" if not specified.
50 Example.
52 rootfstype=ext3
54 rootflags=<mount options>
57 specify additional mount options for the root filesystem. If not
58 set, /etc/fstab of the real root will be parsed for special mount
59 options and mounted accordingly.
60 ro
62 force mounting / and /usr (if it is a separate device) read-only.
63 If none of ro and rw is present, both are mounted according to
64 /etc/fstab.
65 rw
67 force mounting / and /usr (if it is a separate device) read-write.
68 See also ro option.
69 rootfallback=<path to blockdevice>
71 specify the block device to use as the root filesystem, if the
72 normal root cannot be found. This can only be a simple block device
73 with a simple file system, for which the filesystem driver is
74 either compiled in, or added manually to the initramfs. This
75 parameter can be specified multiple times.
76 rd.auto rd.auto=1
78 enable autoassembly of special devices like cryptoLUKS, dmraid,
79 mdraid or lvm. Default is off as of dracut version >= 024.
80 rd.cmdline=ask
82 prompts the user for additional kernel command line parameters
83 rd.fstab=0
85 do not honor special mount options for the root filesystem found in
86 /etc/fstab of the real root.
87 resume=<path to resume partition>
89 resume from a swap partition
90 Example.
92 resume=/dev/disk/by-path/pci-0000:00:1f.1-scsi-0:0:1:0-part1
94 resume=/dev/disk/by-uuid/3f5ad593-4546-4a94-a374-bcfb68aa11f7
95 resume=UUID=3f5ad593-4546-4a94-a374-bcfb68aa11f7
96 rd.skipfsck
99 skip fsck for rootfs and /usr. If you’re mounting /usr read-only
100 and the init system performs fsck before remount, you might want to
101 use this option to avoid duplication.
102 Misc
104 rd.emergency=[reboot|poweroff|halt]
105 specify, what action to execute in case of a critical failure.
106 rd.shell=0 also be specified.
107 rd.driver.blacklist=<drivername>[,<drivername>,...]
109 do not load kernel module <drivername>. This parameter can be
110 specified multiple times.
111 rd.driver.pre=<drivername>[,<drivername>,...]
113 force loading kernel module <drivername>. This parameter can be
114 specified multiple times.
115 rd.driver.post=<drivername>[,<drivername>,...]
117 force loading kernel module <drivername> after all automatic
118 loading modules have been loaded. This parameter can be specified
119 multiple times.
120 rd.retry=<seconds>
122 specify how long dracut should wait for devices to appear. The
123 default is 30 seconds. After 2/3 of the time, degraded raids are
124 force started. If you have hardware, which takes a very long time
125 to announce its drives, you might want to extend this value.
126 rd.noverifyssl
128 accept self-signed certificates for ssl downloads.
129 rd.ctty=<terminal device>
131 specify the controlling terminal for the console. This is useful,
132 if you have multiple "console=" arguments.
133 Debug
135 If you are dropped to an emergency shell, the file
136 /run/initramfs/rdsosreport.txt is created, which can be safed to a (to
137 be mounted by hand) partition (usually /boot) or a USB stick.
138 Additional debugging info can be produced by adding rd.debug to the
139 kernel command line. /run/initramfs/rdsosreport.txt contains all logs
140 and the output of some tools. It should be attached to any report about
141 dracut problems.
142 rd.info
144 print informational output though "quiet" is set
145 rd.shell
147 allow dropping to a shell, if root mounting fails
148 rd.debug
150 set -x for the dracut shell. If systemd is active in the initramfs,
151 all output is logged to the systemd journal, which you can inspect
152 with "journalctl -ab". If systemd is not active, the logs are
153 written to dmesg and /run/initramfs/init.log. If "quiet" is set, it
154 also logs to the console.
155 rd.memdebug=[0-4]
157 Print memory usage info at various points, set the verbose level
158 from 0 to 4.
159 Higher level means more debugging output:
161 0 - no output
163 1 - partial /proc/meminfo
164 2 - /proc/meminfo
165 3 - /proc/meminfo + /proc/slabinfo
166 4 - /proc/meminfo + /proc/slabinfo + tracekomem
167 NOTE: tracekomem is a shell script utilizing kernel trace to track
168 the rough total memory consumption of kernel modules during
169 loading. It may override other trace configurations.
170 rd.break
172 drop to a shell at the end
173 rd.break={cmdline|pre-udev|pre-trigger|initqueue|pre-mount|mount|pre-pivot|cleanup}
175 drop to a shell on defined breakpoint
176 rd.udev.info
178 set udev to loglevel info
179 rd.udev.debug
181 set udev to loglevel debug
182 I18N
184 rd.vconsole.keymap=<keymap base file name>
185 keyboard translation table loaded by loadkeys; taken from keymaps
186 directory; will be written as KEYMAP to /etc/vconsole.conf in the
187 initramfs.
188 Example.
190 rd.vconsole.keymap=de-latin1-nodeadkeys
192 rd.vconsole.keymap.ext=<list of keymap base file names>
195 list of extra keymaps to bo loaded (sep. by space); will be written
196 as EXT_KEYMAP to /etc/vconsole.conf in the initramfs
197 rd.vconsole.unicode
199 boolean, indicating UTF-8 mode; will be written as UNICODE to
200 /etc/vconsole.conf in the initramfs
201 rd.vconsole.font=<font base file name>
203 console font; taken from consolefonts directory; will be written as
204 FONT to /etc/vconsole.conf in the initramfs.
205 Example.
207 rd.vconsole.font=LatArCyrHeb-16
209 rd.vconsole.font.map=<console map base file name>
212 see description of -m parameter in setfont manual; taken from
213 consoletrans directory; will be written as FONT_MAP to
214 /etc/vconsole.conf in the initramfs
215 rd.vconsole.font.unimap=<unicode table base file name>
217 see description of -u parameter in setfont manual; taken from
218 unimaps directory; will be written as FONT_UNIMAP to
219 /etc/vconsole.conf in the initramfs
220 rd.locale.LANG=<locale>
222 taken from the environment; if no UNICODE is defined we set its
223 value in basis of LANG value (whether it ends with ".utf8" (or
224 similar) or not); will be written as LANG to /etc/locale.conf in
225 the initramfs.
226 Example.
228 rd.locale.LANG=pl_PL.utf8
230 rd.locale.LC_ALL=<locale>
233 taken from the environment; will be written as LC_ALL to
234 /etc/locale.conf in the initramfs
235 LVM
237 rd.lvm=0
238 disable LVM detection
239 rd.lvm.vg=<volume group name>
241 only activate the volume groups with the given name. rd.lvm.vg can
242 be specified multiple times on the kernel command line.
243 rd.lvm.lv=<logical volume name>
245 only activate the logical volumes with the given name. rd.lvm.lv
246 can be specified multiple times on the kernel command line.
247 rd.lvm.conf=0
249 remove any /etc/lvm/lvm.conf, which may exist in the initramfs
250 crypto LUKS
252 rd.luks=0
253 disable crypto LUKS detection
254 rd.luks.uuid=<luks uuid>
256 only activate the LUKS partitions with the given UUID. Any "luks-"
257 of the LUKS UUID is removed before comparing to <luks uuid>. The
258 comparisons also matches, if <luks uuid> is only the beginning of
259 the LUKS UUID, so you don’t have to specify the full UUID. This
260 parameter can be specified multiple times.
261 rd.luks.allow-discards=<luks uuid>
263 Allow using of discards (TRIM) requests for LUKS partitions with
264 the given UUID. Any "luks-" of the LUKS UUID is removed before
265 comparing to <luks uuid>. The comparisons also matches, if <luks
266 uuid> is only the beginning of the LUKS UUID, so you don’t have to
267 specify the full UUID. This parameter can be specified multiple
268 times.
269 rd.luks.allow-discards
271 Allow using of discards (TRIM) requests on all LUKS partitions.
272 rd.luks.crypttab=0
274 do not check, if LUKS partition is in /etc/crypttab
275 crypto LUKS - key on removable device support
277 rd.luks.key=<keypath>:<keydev>:<luksdev>
278 keypath is a path to key file to look for. It’s REQUIRED. When
279 keypath ends with .gpg it’s considered to be key encrypted
280 symmetrically with GPG. You will be prompted for password on boot.
281 GPG support comes with crypt-gpg module which needs to be added
282 explicitly.
283 keydev is a device on which key file resides. It might be kernel
285 name of devices (should start with "/dev/"), UUID (prefixed with
286 "UUID=") or label (prefix with "LABEL="). You don’t have to specify
287 full UUID. Just its beginning will suffice, even if its ambiguous.
288 All matching devices will be probed. This parameter is recommended,
289 but not required. If not present, all block devices will be probed,
290 which may significantly increase boot time.
291 If luksdev is given, the specified key will only be applied for
293 that LUKS device. Possible values are the same as for keydev.
294 Unless you have several LUKS devices, you don’t have to specify
295 this parameter. The simplest usage is:
296 Example.
298 rd.luks.key=/foo/bar.key
300 As you see, you can skip colons in such a case.
303 Note
305 dracut pipes key to cryptsetup with -d - argument, therefore
306 you need to pipe to crypsetup luksFormat with -d -, too!
307 Here follows example for key encrypted with GPG:
309 gpg --quiet --decrypt rootkey.gpg | \
311 cryptsetup -d - -v --cipher serpent-cbc-essiv:sha256 \
312 --key-size 256 luksFormat /dev/sda3
313 If you use plain keys, just add path to -d option:
315 cryptsetup -d rootkey.key -v --cipher serpent-cbc-essiv:sha256 \
317 --key-size 256 luksFormat /dev/sda3
318 MD RAID
320 rd.md=0
321 disable MD RAID detection
322 rd.md.imsm=0
324 disable MD RAID for imsm/isw raids, use DM RAID instead
325 rd.md.ddf=0
327 disable MD RAID for SNIA ddf raids, use DM RAID instead
328 rd.md.conf=0
330 ignore mdadm.conf included in initramfs
331 rd.md.waitclean=1
333 wait for any resync, recovery, or reshape activity to finish before
334 continuing
335 rd.md.uuid=<md raid uuid>
337 only activate the raid sets with the given UUID. This parameter can
338 be specified multiple times.
339 DM RAID
341 rd.dm=0
342 disable DM RAID detection
343 rd.dm.uuid=<dm raid uuid>
345 only activate the raid sets with the given UUID. This parameter can
346 be specified multiple times.
347 FIPS
349 rd.fips
350 enable FIPS
351 boot=<boot device>
353 specify the device, where /boot is located.
354 Example.
356 boot=/dev/sda1
358 boot=/dev/disk/by-path/pci-0000:00:1f.1-scsi-0:0:1:0-part1
359 boot=UUID=<uuid>
360 boot=LABEL=<label>
361 rd.fips.skipkernel
364 skip checksum check of the kernel image. Useful, if the kernel
365 image is not in a separate boot partition.
366 Network
368 Important
369 It is recommended to either bind an interface to a MAC with the
370 ifname argument, or to use the systemd-udevd predictable network
371 interface names.
372 Predictable network interface device names based on:
374 · firmware/bios-provided index numbers for on-board devices
376 · firmware-provided pci-express hotplug slot index number
378 · physical/geographical location of the hardware
380 · the interface’s MAC address
382 See:
384 http://www.freedesktop.org/wiki/Software/systemd/PredictableNetworkInterfaceNames
385 Two character prefixes based on the type of interface:
387 en
389 ethernet
390 wl
392 wlan
393 ww
395 wwan
396 Type of names:
398 o<index>
400 on-board device index number
401 s<slot>[f<function>][d<dev_id>]
403 hotplug slot index number
404 x<MAC>
406 MAC address
407 [P<domain>]p<bus>s<slot>[f<function>][d<dev_id>]
409 PCI geographical location
410 [P<domain>]p<bus>s<slot>[f<function>][u<port>][..][c<config>][i<interface>]
412 USB port number chain
413 All multi-function PCI devices will carry the [f<function>] number
415 in the device name, including the function 0 device.
416 When using PCI geography, The PCI domain is only prepended when it
418 is not 0.
419 For USB devices the full chain of port numbers of hubs is composed.
421 If the name gets longer than the maximum number of 15 characters,
422 the name is not exported. The usual USB configuration == 1 and
423 interface == 0 values are suppressed.
424 PCI ethernet card with firmware index "1"
426 · eno1
428 PCI ethernet card in hotplug slot with firmware index number
430 · ens1
432 PCI ethernet multi-function card with 2 ports
434 · enp2s0f0
436 · enp2s0f1
438 PCI wlan card
440 · wlp3s0
442 USB built-in 3G modem
444 · wwp0s29u1u4i6
446 USB Android phone
448 · enp0s29u1u2
450 ip={dhcp|on|any|dhcp6|auto6|either6}
452 dhcp|on|any
454 get ip from dhcp server from all interfaces. If root=dhcp, loop
455 sequentially through all interfaces (eth0, eth1, ...) and use
456 the first with a valid DHCP root-path.
457 auto6
459 IPv6 autoconfiguration
460 dhcp6
462 IPv6 DHCP
463 either6
465 if auto6 fails, then dhcp6
466 ip=<interface>:{dhcp|on|any|dhcp6|auto6}[:[<mtu>][:<macaddr>]]
468 This parameter can be specified multiple times.
469 dhcp|on|any|dhcp6
471 get ip from dhcp server on a specific interface
472 auto6
474 do IPv6 autoconfiguration
475 <macaddr>
477 optionally set <macaddr> on the <interface>. This cannot be
478 used in conjunction with the ifname argument for the same
479 <interface>.
480 ip=<client-IP>:[<peer>]:<gateway-IP>:<netmask>:<client_hostname>:<interface>:{none|off|dhcp|on|any|dhcp6|auto6|ibft}[:[<mtu>][:<macaddr>]]
482 explicit network configuration. If you want do define a IPv6
483 address, put it in brackets (e.g. [2001:DB8::1]). This parameter
484 can be specified multiple times. <peer> is optional and is the
485 address of the remote endpoint for pointopoint interfaces and it
486 may be followed by a slash and a decimal number, encoding the
487 network prefix length.
488 <macaddr>
490 optionally set <macaddr> on the <interface>. This cannot be
491 used in conjunction with the ifname argument for the same
492 <interface>.
493 ip=<client-IP>:[<peer>]:<gateway-IP>:<netmask>:<client_hostname>:<interface>:{none|off|dhcp|on|any|dhcp6|auto6|ibft}[:[<dns1>][:<dns2>]]
495 explicit network configuration. If you want do define a IPv6
496 address, put it in brackets (e.g. [2001:DB8::1]). This parameter
497 can be specified multiple times. <peer> is optional and is the
498 address of the remote endpoint for pointopoint interfaces and it
499 may be followed by a slash and a decimal number, encoding the
500 network prefix length.
501 ifname=<interface>:<MAC>
503 Assign network device name <interface> (ie "bootnet") to the NIC
504 with MAC <MAC>.
505 Warning
507 Do not use the default kernel naming scheme for the interface
508 name, as it can conflict with the kernel names. So, don’t use
509 "eth[0-9]+" for the interface name. Better name it "bootnet" or
510 "bluesocket".
511 rd.route=<net>/<netmask>:<gateway>[:<interface>]
513 Add a static route with route options, which are separated by a
514 colon. IPv6 addresses have to be put in brackets.
515 Example.
517 rd.route=192.168.200.0/24:192.168.100.222:ens10
519 rd.route=192.168.200.0/24:192.168.100.222
520 rd.route=192.168.200.0/24::ens10
521 rd.route=[2001:DB8:3::/8]:[2001:DB8:2::1]:ens10
522 bootdev=<interface>
525 specify network interface to use routing and netroot information
526 from. Required if multiple ip= lines are used.
527 BOOTIF=<MAC>
529 specify network interface to use routing and netroot information
530 from.
531 rd.bootif=0
533 Disable BOOTIF parsing, which is provided by PXE
534 nameserver=<IP> [nameserver=<IP> ...]
536 specify nameserver(s) to use
537 biosdevname=0
539 boolean, turn off biosdevname network interface renaming
540 rd.neednet=1
542 boolean, bring up network even without netroot set
543 vlan=<vlanname>:<phydevice>
545 Setup vlan device named <vlanname> on <phydeivce>. We support the
546 four styles of vlan names: VLAN_PLUS_VID (vlan0005),
547 VLAN_PLUS_VID_NO_PAD (vlan5), DEV_PLUS_VID (eth0.0005),
548 DEV_PLUS_VID_NO_PAD (eth0.5)
549 bond=<bondname>[:<bondslaves>:[:<options>]]
551 Setup bonding device <bondname> on top of <bondslaves>.
552 <bondslaves> is a comma-separated list of physical (ethernet)
553 interfaces. <options> is a comma-separated list on bonding options
554 (modinfo bonding for details) in format compatible with
555 initscripts. If <options> includes multi-valued arp_ip_target
556 option, then its values should be separated by semicolon. Bond
557 without parameters assumes bond=bond0:eth0,eth1:mode=balance-rr
558 team=<teammaster>:<teamslaves>
560 Setup team device <teammaster> on top of <teamslaves>. <teamslaves>
561 is a comma-separated list of physical (ethernet) interfaces.
562 bridge=<bridgename>:<ethnames>
564 Setup bridge <bridgename> with <ethnames>. <ethnames> is a
565 comma-separated list of physical (ethernet) interfaces. Bridge
566 without parameters assumes bridge=br0:eth0
567 NFS
569 root=[<server-ip>:]<root-dir>[:<nfs-options>]
570 mount nfs share from <server-ip>:/<root-dir>, if no server-ip is
571 given, use dhcp next_server. If server-ip is an IPv6 address it has
572 to be put in brackets, e.g. [2001:DB8::1]. NFS options can be
573 appended with the prefix ":" or "," and are seperated by ",".
574 root=nfs:[<server-ip>:]<root-dir>[:<nfs-options>],
576 root=nfs4:[<server-ip>:]<root-dir>[:<nfs-options>], root={dhcp|dhcp6}
577 root=dhcp alone directs initrd to look at the DHCP root-path where
578 NFS options can be specified.
579 Example.
581 root-path=<server-ip>:<root-dir>[,<nfs-options>]
583 root-path=nfs:<server-ip>:<root-dir>[,<nfs-options>]
584 root-path=nfs4:<server-ip>:<root-dir>[,<nfs-options>]
585 root=/dev/nfs nfsroot=[<server-ip>:]<root-dir>[:<nfs-options>]
588 Deprecated! kernel Documentation_/filesystems/nfsroot.txt_ defines
589 this method. This is supported by dracut, but not recommended.
590 rd.nfs.domain=<NFSv4 domain name>
592 Set the NFSv4 domain name. Will overwrite the settings in
593 /etc/idmap.conf.
594 rd.net.dhcp.retry=<cnt>
596 If this option is set, dracut will try to connect via dhcp <cnt>
597 times before failing. Default is 1.
598 rd.net.timeout.dhcp=<arg>
600 If this option is set, dhclient is called with "-timeout <arg>".
601 rd.net.timeout.iflink=<seconds>
603 Wait <seconds> until link shows up. Default is 60 seconds.
604 rd.net.timeout.ifup=<seconds>
606 Wait <seconds> until link has state "UP". Default is 20 seconds.
607 rd.net.timeout.route=<seconds>
609 Wait <seconds> until route shows up. Default is 20 seconds.
610 rd.net.timeout.ipv6dad=<seconds>
612 Wait <seconds> until IPv6 DAD is finished. Default is 50 seconds.
613 rd.net.timeout.ipv6auto=<seconds>
615 Wait <seconds> until IPv6 automatic addresses are assigned. Default
616 is 40 seconds.
617 rd.net.timeout.carrier=<seconds>
619 Wait <seconds> until carrier is recognized. Default is 5 seconds.
620 CIFS
622 root=cifs://[<username>[:<password>]@]<server-ip>:<root-dir>
623 mount cifs share from <server-ip>:/<root-dir>, if no server-ip is
624 given, use dhcp next_server. if server-ip is an IPv6 address it has
625 to be put in brackets, e.g. [2001:DB8::1]. If a username or
626 password are not specified as part of the root, then they must be
627 passed on the command line through cifsuser/cifspass.
628 Warning
630 Passwords specified on the kernel command line are visible for
631 all users via the file /proc/cmdline and via dmesg or can be
632 sniffed on the network, when using DHCP with DHCP root-path.
633 cifsuser=<username>
635 Set the cifs username, if not specified as part of the root.
636 cifspass=<password>
638 Set the cifs password, if not specified as part of the root.
639 Warning
641 Passwords specified on the kernel command line are visible for
642 all users via the file /proc/cmdline and via dmesg or can be
643 sniffed on the network, when using DHCP with DHCP root-path.
644 iSCSI
646 root=iscsi:[<username>:<password>[:<reverse>:<password>]@][<servername>]:[<protocol>]:[<port>][:[<iscsi_iface_name>]:[<netdev_name>]]:[<LUN>]:<targetname>
647 protocol defaults to "6", LUN defaults to "0". If the "servername"
648 field is provided by BOOTP or DHCP, then that field is used in
649 conjunction with other associated fields to contact the boot server
650 in the Boot stage. However, if the "servername" field is not
651 provided, then the "targetname" field is then used in the Discovery
652 Service stage in conjunction with other associated fields. See
653 rfc4173[1].
654 Warning
656 Passwords specified on the kernel command line are visible for
657 all users via the file /proc/cmdline and via dmesg or can be
658 sniffed on the network, when using DHCP with DHCP root-path.
659 Example.
661 root=iscsi:192.168.50.1::::iqn.2009-06.dracut:target0
663 If servername is an IPv6 address, it has to be put in brackets:
666 Example.
668 root=iscsi:[2001:DB8::1]::::iqn.2009-06.dracut:target0
670 root=???
673 netroot=iscsi:[<username>:<password>[:<reverse>:<password>]@][<servername>]:[<protocol>]:[<port>][:[<iscsi_iface_name>]:[<netdev_name>]]:[<LUN>]:<targetname>
674 ...
675 multiple netroot options allow setting up multiple iscsi disks:
676 Example.
678 root=UUID=12424547
680 netroot=iscsi:192.168.50.1::::iqn.2009-06.dracut:target0
681 netroot=iscsi:192.168.50.1::::iqn.2009-06.dracut:target1
682 If servername is an IPv6 address, it has to be put in brackets:
685 Example.
687 netroot=iscsi:[2001:DB8::1]::::iqn.2009-06.dracut:target0
689 Warning
692 Passwords specified on the kernel command line are visible for
693 all users via the file /proc/cmdline and via dmesg or can be
694 sniffed on the network, when using DHCP with DHCP root-path.
695 You may want to use rd.iscsi.firmware.
696 root=??? rd.iscsi.initiator=<initiator> rd.iscsi.target.name=<target
698 name> rd.iscsi.target.ip=<target ip> rd.iscsi.target.port=<target port>
699 rd.iscsi.target.group=<target group> rd.iscsi.username=<username>
700 rd.iscsi.password=<password> rd.iscsi.in.username=<in username>
701 rd.iscsi.in.password=<in password>
702 manually specify all iscsistart parameter (see iscsistart --help)
703 Warning
705 Passwords specified on the kernel command line are visible for
706 all users via the file /proc/cmdline and via dmesg or can be
707 sniffed on the network, when using DHCP with DHCP root-path.
708 You may want to use rd.iscsi.firmware.
709 root=??? netroot=iscsi rd.iscsi.firmware=1
711 will read the iscsi parameter from the BIOS firmware
712 rd.iscsi.param=<param>
714 <param> will be passed as "--param <param>" to iscsistart. This
715 parameter can be specified multiple times.
716 Example.
718 "netroot=iscsi rd.iscsi.firmware=1 rd.iscsi.param=node.session.timeo.replacement_timeout=30"
720 will result in
723 iscsistart -b --param node.session.timeo.replacement_timeout=30
725 rd.iscsi.ibft rd.iscsi.ibft=1: Turn on iBFT autoconfiguration for the
727 interfaces
728 rd.iscsi.waitnet=0: Turn off waiting for all interfaces to be up before
730 trying to login to the iSCSI targets.
731 rd.iscsi.testroute=0: Turn off checking, if the route to the iSCSI
733 target IP is possible before trying to login.
734 FCoE
736 fcoe=<edd|interface|MAC>:{dcb|nodcb}
737 Try to connect to a FCoE SAN through the NIC specified by
738 <interface> or <MAC> or EDD settings. For the second argument,
739 currently only nodcb is supported. This parameter can be specified
740 multiple times.
741 Note
743 letters in the MAC-address must be lowercase!
744 NBD
746 root=???
747 netroot=nbd:<server>:<port>[:<fstype>[:<mountopts>[:<nbdopts>]]]
748 mount nbd share from <server>
749 root=dhcp with dhcp
751 root-path=nbd:<server>:<port>[:<fstype>[:<mountopts>[:<nbdopts>]]]
752 root=dhcp alone directs initrd to look at the DHCP root-path where
753 NBD options can be specified. This syntax is only usable in cases
754 where you are directly mounting the volume as the rootfs.
755 DASD
757 rd.dasd=....
758 same syntax as the kernel module parameter (s390 only)
759 ZFCP
761 rd.zfcp=<zfcp adaptor device bus ID>,<WWPN>,<FCPLUN>
762 rd.zfcp can be specified multiple times on the kernel command line.
763 Example.
765 rd.zfcp=0.0.4000,0x5005076300C213e9,0x5022000000000000
767 rd.zfcp.conf=0
770 ignore zfcp.conf included in the initramfs
771 ZNET
773 rd.znet=<nettype>,<subchannels>,<options>
774 rd.znet can be specified multiple times on the kernel command line.
775 Example.
777 rd.znet=qeth,0.0.0600,0.0.0601,0.0.0602,layer2=1,portname=foo
779 rd.znet=ctc,0.0.0600,0.0.0601,protocol=bar
780 Booting live images
783 Dracut offers multiple options for live booted images:
784 squashfs with read-only filesystem image
786 The system will boot with a read only filesystem from the squashfs
787 and apply a writable device mapper snapshot over the read only
788 filesystem. Using this method ensures a relatively fast boot and
789 lower RAM usage. Users must be careful to avoid writing too many
790 blocks to the snapshot volume. Once the blocks of the snapshot are
791 exhaused, the live filesystem becomes unusable and requires a
792 reboot.
793 The filesystem structure is expected to be:
795 squashfs.img | Squashfs downloaded via network
797 !(mount)
798 /LiveOS
799 |- ext3fs.img | Filesystem image to mount read-only
800 !(mount)
801 /bin | Live filesystem
802 /boot |
803 /dev |
804 ... |
805 Dracut uses this method of live booting by default. No additional
807 command line options are required other than root=live:<URL> to
808 specify the location of your squashed filesystem.
809 writable filesystem image
811 The system will retrieve a compressed filesystem image, connect it
812 to a loopback device, and mount it as a writable volume. More RAM
813 is required during boot but the live filesystem is easier to manage
814 if it becomes full. Users can make a filesystem image of any size
815 and that size will be maintained when the system boots.
816 The filesystem structure is expected to be:
818 rootfs.tgz | Compressed tarball containing fileystem image
820 !(unpack)
821 /rootfs.img | Filesystem image
822 !(mount)
823 /bin | Live filesystem
824 /boot |
825 /dev |
826 ... |
827 To use this boot option, ensure that rd.writable_fsimg=1 is in your
829 kernel command line and add the root=live:<URL> to specify the
830 location of your compressed filesystem image tarball.
831 root=live:<url>
833 Boots a live image retrieved from <url>. Valid handlers: http,
834 httpd, ftp, tftp.
835 Example.
837 root=live:http://example.com/liveboot.img
839 root=live:ftp://ftp.example.com/liveboot.img
840 rd.live.debug=1
843 Enables debug output from the live boot process.
844 rd.live.dir=<path>
846 Specifies the directory within the squashfs where the ext3fs.img or
847 rootfs.img can be found. By default, this is LiveOS.
848 rd.live.ram=1
850 Copy the complete image to RAM and use this for booting. This is
851 useful when the image resides on i.e. a DVD which needs to be
852 ejected later on.
853 rd.live.overlay=<devspec>:_(<pathspec>|auto) Allow the usage of a
855 permanent overlay. <devspec> specifies the path to a device with a
856 mountable filesystem. <pathspec> is the path to a file within that
857 filesystem, which shall be used to persist the changes made to the
858 device specified by root=live:<url>__ option.
859 +
861 Example.
863 rd.live.overlay=/dev/sdb1:persistent-overlay.img
865 rd.live.overlay.thin=1
869 Enables the usage of thin snapshots instead of classic dm
870 snapshots. The advantage of thin snapshots is, that they support
871 discards, and will free blocks which are not claimed by the
872 filesystem. In this use case this means, that memory is given back
873 to the kernel, when the filesystem does not claim it anymore.
874 rd.writable.fsimg=1
876 Enables writable filesystem support. The system will boot with a
877 fully writable filesystem without snapshots (see notes above about
878 available live boot options). You can use the rootflags option to
879 set mount options for the live filesystem as well (see
880 documentation about rootflags in the Standard section above). This
881 implies that the whole image is copied to RAM before the boot
882 continues.
883 Note
885 There must be enough free RAM available to hold the complete
886 image.
887 This method is very suitable for diskless boots.
888 Plymouth Boot Splash
890 plymouth.enable=0
891 disable the plymouth bootsplash completely.
892 rd.plymouth=0
894 disable the plymouth bootsplash only for the initramfs.
895 Kernel keys
897 masterkey=<kernel master key path name>
898 Set the path name of the kernel master key.
899 Example.
901 masterkey=/etc/keys/kmk-trusted.blob
903 masterkeytype=<kernel master key type>
906 Set the type of the kernel master key.
907 Example.
909 masterkeytype=trusted
911 evmkey=<EVM key path name>
914 Set the path name of the EVM key.
915 Example.
917 evmkey=/etc/keys/evm-trusted.blob
919 ecryptfskey=<eCryptfs key path name>
922 Set the path name of the eCryptfs key.
923 Example.
925 ecryptfskey=/etc/keys/ecryptfs-trusted.blob
927 Deprecated, renamed Options
930 Here is a list of options, which were used in dracut prior to version
931 008, and their new replacement.
932 rdbreak
934 rd.break
935 rd_CCW
937 rd.ccw
938 rd_DASD_MOD
940 rd.dasd
941 rd_DASD
943 rd.dasd
944 rdinitdebug rdnetdebug
946 rd.debug
947 rd_NO_DM
949 rd.dm=0
950 rd_DM_UUID
952 rd.dm.uuid
953 rdblacklist
955 rd.driver.blacklist
956 rdinsmodpost
958 rd.driver.post
959 rdloaddriver
961 rd.driver.pre
962 rd_NO_FSTAB
964 rd.fstab=0
965 rdinfo
967 rd.info
968 check
970 rd.live.check
971 rdlivedebug
973 rd.live.debug
974 live_dir
976 rd.live.dir
977 liveimg
979 rd.live.image
980 overlay
982 rd.live.overlay
983 readonly_overlay
985 rd.live.overlay.readonly
986 reset_overlay
988 rd.live.overlay.reset
989 live_ram
991 rd.live.ram
992 rd_NO_CRYPTTAB
994 rd.luks.crypttab=0
995 rd_LUKS_KEYDEV_UUID
997 rd.luks.keydev.uuid
998 rd_LUKS_KEYPATH
1000 rd.luks.keypath
1001 rd_NO_LUKS
1003 rd.luks=0
1004 rd_LUKS_UUID
1006 rd.luks.uuid
1007 rd_NO_LVMCONF
1009 rd.lvm.conf
1010 rd_LVM_LV
1012 rd.lvm.lv
1013 rd_NO_LVM
1015 rd.lvm=0
1016 rd_LVM_SNAPSHOT
1018 rd.lvm.snapshot
1019 rd_LVM_SNAPSIZE
1021 rd.lvm.snapsize
1022 rd_LVM_VG
1024 rd.lvm.vg
1025 rd_NO_MDADMCONF
1027 rd.md.conf=0
1028 rd_NO_MDIMSM
1030 rd.md.imsm=0
1031 rd_NO_MD
1033 rd.md=0
1034 rd_MD_UUID
1036 rd.md.uuid
1037 rd_NFS_DOMAIN
1039 rd.nfs.domain
1040 iscsi_initiator
1042 rd.iscsi.initiator
1043 iscsi_target_name
1045 rd.iscsi.target.name
1046 iscsi_target_ip
1048 rd.iscsi.target.ip
1049 iscsi_target_port
1051 rd.iscsi.target.port
1052 iscsi_target_group
1054 rd.iscsi.target.group
1055 iscsi_username
1057 rd.iscsi.username
1058 iscsi_password
1060 rd.iscsi.password
1061 iscsi_in_username
1063 rd.iscsi.in.username
1064 iscsi_in_password
1066 rd.iscsi.in.password
1067 iscsi_firmware
1069 rd.iscsi.firmware=0
1070 rd_NO_PLYMOUTH
1072 rd.plymouth=0
1073 rd_retry
1075 rd.retry
1076 rdshell
1078 rd.shell
1079 rd_NO_SPLASH
1081 rd.splash
1082 rdudevdebug
1084 rd.udev.debug
1085 rdudevinfo
1087 rd.udev.info
1088 rd_NO_ZFCPCONF
1090 rd.zfcp.conf=0
1091 rd_ZFCP
1093 rd.zfcp
1094 rd_ZNET
1096 rd.znet
1097 KEYMAP
1099 vconsole.keymap
1100 KEYTABLE
1102 vconsole.keymap
1103 SYSFONT
1105 vconsole.font
1106 CONTRANS
1108 vconsole.font.map
1109 UNIMAP
1111 vconsole.font.unimap
1112 UNICODE
1114 vconsole.unicode
1115 EXT_KEYMAP
1117 vconsole.keymap.ext
1118 Configuration in the Initramfs
1120 /etc/conf.d/
1121 Any files found in /etc/conf.d/ will be sourced in the initramfs to
1122 set initial values. Command line options will override these values
1123 set in the configuration files.
1124 /etc/cmdline
1126 Can contain additional command line options. Deprecated, better use
1127 /etc/cmdline.d/*.conf.
1128 /etc/cmdline.d/*.conf
1130 Can contain additional command line options.
1131
1133 Harald Hoyer
1134
1136 dracut(8) dracut.conf(5)
1137
1139 1. rfc4173
1140 http://tools.ietf.org/html/rfc4173#section-5
1141dracut 11/02/2018 DRACUT.CMDLINE(7)