DRACUT.CMDLINE(7)

NAME
dracut.cmdline - dracut kernel command line options

DESCRIPTION

The root device used by the kernel is specified in the boot configuration file on the kernel command line, as always.

The traditional root=/dev/sda1 style device specification is allowed, but not encouraged. The root device should better be identified by LABEL or UUID. If a label is used, as in root=LABEL=<label_of_root> the initramfs will search all available devices for a filesystem with the appropriate label, and mount that device as the root filesystem. root=UUID=<uuidnumber> will mount the partition with that UUID as the root filesystem.

In the following all kernel command line parameters, which are processed by dracut, are described.

"rd.*" parameters mentioned without "=" are boolean parameters. They can be turned on/off by setting them to {0|1}. If the assignment with "=" is missing "=1" is implied. For example rd.info can be turned off with rd.info=0 or turned on with rd.info=1 or rd.info. The last value in the kernel command line is the value, which is honored.

  Standard

init=<path to real init>
    specify the path to the init programm to be started after the initramfs has finished

root=<path to blockdevice>
    specify the block device to use as the root filesystem.

    E.g.:

        root=/dev/sda1
        root=/dev/disk/by-path/pci-0000:00:1f.1-scsi-0:0:1:0-part1
        root=/dev/disk/by-label/Root
        root=LABEL=Root
        root=/dev/disk/by-uuid/3f5ad593-4546-4a94-a374-bcfb68aa11f7
        root=UUID=3f5ad593-4546-4a94-a374-bcfb68aa11f7

rootfstype=<filesystem type>
    "auto" if not specified, e.g.:

        rootfstype=ext3

rootflags=<mount options>
    specify additional mount options for the root filesystem. If not set, /etc/fstab of the real root will be parsed for special mount options and mounted accordingly.

rd.fstab=0
    do not honor special mount options for the root filesystem found in /etc/fstab of the real root.

resume=<path to resume partition>

+ E.g.:

+

    resume=/dev/disk/by-path/pci-0000:00:1f.1-scsi-0:0:1:0-part1
    resume=/dev/disk/by-uuid/3f5ad593-4546-4a94-a374-bcfb68aa11f7
    resume=UUID=3f5ad593-4546-4a94-a374-bcfb68aa11f7

  Misc

rd.driver.blacklist=<drivername>[,<drivername>,...]
    do not load kernel module <drivername>. This parameter can be specified multiple times.

rd.driver.pre=<drivername>[,<drivername>,...]
    force loading kernel module <drivername>. This parameter can be specified multiple times.

rd.driver.post=<drivername>[,<drivername>,...]
    force loading kernel module <drivername> after all automatic loading modules have been loaded. This parameter can be specified multiple times.

  Debug

rd.info
    print informational output though "quiet" is set

rd.shell
    allow dropping to a shell, if root mounting fails

rd.debug
    set -x for the dracut shell and logs to dmesg, console and /run/initramfs/init.log

rd.break
    drop to a shell at the end

rd.break={cmdline|pre-udev|pre-trigger|initqueue|pre-mount|mount|pre-pivot|pre-pivot-cleanup}
    drop to a shell on defined breakpoint

rd.udev.info
    set udev to loglevel info

rd.udev.debug
    set udev to loglevel debug

  I18N

vconsole.keymap=<keymap base file name>
    keyboard translation table loaded by loadkeys; taken from keymaps directory; will be written as KEYMAP to /etc/vconsole.conf in the initramfs, e.g.:

        vconsole.keymap=de-latin1-nodeadkeys

vconsole.keymap.ext=<list of keymap base file names>
    list of extra keymaps to bo loaded (sep. by space); will be written as EXT_KEYMAP to /etc/vconsole.conf in the initramfs

vconsole.unicode[={0|1}]
    boolean, indicating UTF-8 mode; will be written as UNICODE to /etc/vconsole.conf in the initramfs

vconsole.font=<font base file name>
    console font; taken from consolefonts directory; will be written as FONT to /etc/vconsole.conf in the initramfs; e.g.:

        vconsole.font=LatArCyrHeb-16

vconsole.font.map=<console map base file name>
    see description of -m parameter in setfont manual; taken from consoletrans directory; will be written as FONT_MAP to /etc/vconsole.conf in the initramfs

vconsole.font.unimap=<unicode table base file name>
    see description of -u parameter in setfont manual; taken from unimaps directory; will be written as FONT_UNIMAP to /etc/vconsole.conf in the initramfs

locale.LANG=<locale>
    taken from the environment; if no UNICODE is defined we set its value in basis of LANG value (whether it ends with ".utf8" (or similar) or not); will be written as LANG to /etc/locale.conf in the initramfs; e.g.:

        locale.LANG=pl_PL.utf8

locale.LC_ALL=<locale>
    taken from the environment; will be written as LC_ALL to /etc/locale.conf in the initramfs

  LVM

rd.lvm=0
    disable LVM detection

rd.lvm.vg=<volume group name>
    only activate the volume groups with the given name. rd.lvm.vg can be specified multiple times on the kernel command line.

rd.lvm.lv=<logical volume name>
    only activate the logical volumes with the given name. rd.lvm.lv can be specified multiple times on the kernel command line.

rd.lvm.conf=0
    remove any /etc/lvm/lvm.conf, which may exist in the initramfs

  crypto LUKS

rd.luks=0
    disable crypto LUKS detection

rd.luks.uuid=<luks uuid>
    only activate the LUKS partitions with the given UUID. Any "luks-" of the LUKS UUID is removed before comparing to <luks uuid>. The comparisons also matches, if <luks uuid> is only the beginning of the LUKS UUID, so you don’t have to specify the full UUID. This parameter can be specified multiple times.

rd.luks.allow-discards=<luks uuid>
    Allow using of discards (TRIM) requests for LUKS partitions with the given UUID. Any "luks-" of the LUKS UUID is removed before comparing to <luks uuid>. The comparisons also matches, if <luks uuid> is only the beginning of the LUKS UUID, so you don’t have to specify the full UUID. This parameter can be specified multiple times.

**rd.luks.allow-discards
    Allow using of discards (TRIM) requests on all LUKS partitions.

rd.luks.crypttab=0
    do not check, if LUKS partition is in /etc/crypttab

  crypto LUKS - key on removable device support

rd.luks.key=<keypath>:<keydev>:<luksdev>
    keypath is a path to key file to look for. It’s REQUIRED. When keypath ends with .gpg it’s considered to be key encrypted symmetrically with GPG. You will be prompted for password on boot. GPG support comes with crypt-gpg module which needs to be added explicitly.

    keydev is a device on which key file resides. It might be kernel name of devices (should start with "/dev/"), UUID (prefixed with "UUID=") or label (prefix with "LABEL="). You don’t have to specify full UUID. Just its beginning will suffice, even if its ambiguous. All matching devices will be probed. This parameter is recommended, but not required. If not present, all block devices will be probed, which may significantly increase boot time.

    If luksdev is given, the specified key will only be applied for that LUKS device. Possible values are the same as for keydev. Unless you have several LUKS devices, you don’t have to specify this parameter. The simplest usage is:

        rd.luks.key=/foo/bar.key

    As you see, you can skip colons in such a case.

  MD RAID

rd.md=0
    disable MD RAID detection

rd.md.imsm=0
    disable MD RAID for imsm/isw raids, use DM RAID instead

rd.md.ddf=0
    disable MD RAID for SNIA ddf raids, use DM RAID instead

rd.md.conf=0
    ignore mdadm.conf included in initramfs

rd.md.waitclean=1
    wait for any resync, recovery, or reshape activity to finish before continuing

rd.md.uuid=<md raid uuid>
    only activate the raid sets with the given UUID. This parameter can be specified multiple times.

  DM RAID

rd.dm=0
    disable DM RAID detection

rd.dm.uuid=<dm raid uuid>
    only activate the raid sets with the given UUID. This parameter can be specified multiple times.

  FIPS

rd.fips
    enable FIPS

boot=<boot device>
    specify the device, where /boot is located. e.g.

        boot=/dev/sda1
        boot=/dev/disk/by-path/pci-0000:00:1f.1-scsi-0:0:1:0-part1
        boot=UUID=<uuid>
        boot=LABEL=<label>

rd.fips.skipkernel
    skip checksum check of the kernel image. Useful, if the kernel image is not in a separate boot partition.

  Network

ip={dhcp|on|any|dhcp6|auto6|ibft}

    dhcp|on|any
        get ip from dhcp server from all interfaces. If root=dhcp, loop sequentially through all interfaces (eth0, eth1, ...) and use the first with a valid DHCP root-path.

    auto6
        IPv6 autoconfiguration

    dhcp6
        IPv6 DHCP

    ibft
        iBFT autoconfiguration

ip=<interface>:{dhcp|on|any|dhcp6|auto6}[:[<mtu>][:<macaddr>]]
    This parameter can be specified multiple times.

    dhcp|on|any|dhcp6
        get ip from dhcp server on a specific interface

    auto6
        do IPv6 autoconfiguration

    <macaddr>
        optionally set <macaddr> on the <interface>

ip=<client-IP>:<server-IP>:<gateway-IP>:<netmask>:<client_hostname>:<interface>:{none|off|dhcp|on|any|dhcp6|auto6|ibft}[:[<mtu>][:<macaddr>]]
    explicit network configuration. If you want do define a IPv6 address, put it in brackets (e.g. [2001:DB8::1]). This parameter can be specified multiple times.

    <macaddr>
        optionally set <macaddr> on the <interface>

ifname=<interface>:<MAC>
    Assign network device name <interface> (ie eth0) to the NIC with MAC <MAC>. Note: If you use this option you must specify an ifname= argument for all interfaces used in ip= or fcoe= arguments. This parameter can be specified multiple times.

bootdev=<interface>
    specify network interface to use routing and netroot information from. Required if multiple ip= lines are used.

nameserver=<IP> [nameserver=<IP> ...]
    specify nameserver(s) to use

biosdevname=0
    boolean, turn off biosdevname network interface renaming

rd.neednet=1
    boolean, bring up network even without netroot set

  NFS

root=<root-dir>[:<nfs-options>]
    mount nfs share from <server-ip>:/<root-dir>, if no server-ip is given, use dhcp next_server. if server-ip is an IPv6 address it has to be put in brackets, e.g. [2001:DB8::1]. NFS options can be appended with the prefix ":" or "," and are seperated by ",".

root=nfs:<root-dir>[:<nfs-options>], root=nfs4:<root-dir>[:<nfs-options>], root={dhcp|dhcp6}
    root=dhcp alone directs initrd to look at the DHCP root-path where NFS options can be specified.

            root-path=<server-ip>:<root-dir>[,<nfs-options>]
            root-path=nfs:<server-ip>:<root-dir>[,<nfs-options>]
            root-path=nfs4:<server-ip>:<root-dir>[,<nfs-options>]

root=/dev/nfs nfsroot=<root-dir>[:<nfs-options>]
    Deprecated! kernel Documentation_/filesystems/nfsroot.txt_ defines this method. This is supported by dracut, but not recommended.

rd.nfs.domain=<NFSv4 domain name>
    Set the NFSv4 domain name. Will overwrite the settings in /etc/idmap.conf.

  iSCSI

root=iscsi:[<username>:<password>[:<reverse>:<password>]@][<servername>]:[<protocol>]:[<port>][:[<iscsi_iface_name>]:[<netdev_name>]]:[<LUN>]:<targetname>
    protocol defaults to "6", LUN defaults to "0". If the "servername" field is provided by BOOTP or DHCP, then that field is used in conjunction with other associated fields to contact the boot server in the Boot stage. However, if the "servername" field is not provided, then the "targetname" field is then used in the Discovery Service stage in conjunction with other associated fields. See rfc4173[1]. e.g.:

        root=iscsi:192.168.50.1::::iqn.2009-06.dracut:target0

    If servername is an IPv6 address, it has to be put in brackets. e.g.:

        root=iscsi:[2001:DB8::1]::::iqn.2009-06.dracut:target0

root=??? netroot=iscsi:[<username>:<password>[:<reverse>:<password>]@][<servername>]:[<protocol>]:[<port>][:[<iscsi_iface_name>]:[<netdev_name>]]:[<LUN>]:<targetname> ...
    multiple netroot options allow setting up multiple iscsi disks. e.g.:

        root=UUID=12424547
        netroot=iscsi:192.168.50.1::::iqn.2009-06.dracut:target0
        netroot=iscsi:192.168.50.1::::iqn.2009-06.dracut:target1

    If servername is an IPv6 address, it has to be put in brackets. e.g.:

        netroot=iscsi:[2001:DB8::1]::::iqn.2009-06.dracut:target0

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>
    manually specify all iscsistart parameter (see iscsistart --help)

root=??? netroot=iscsi rd.iscsi.firmware=1
    will read the iscsi parameter from the BIOS firmware

rd.iscsi.param=<param>
    <param> will be passed as "--param <param>" to iscsistart. This parameter can be specified multiple times. e.g.:

        "netroot=iscsi iscsi_firmware rd.iscsi.param=node.session.timeo.replacement_timeout=30"

    will result in

        iscsistart -b --param node.session.timeo.replacement_timeout=30

  FCoE

fcoe=<edd|interface|MAC>:{dcb|nodcb}
    Try to connect to a FCoE SAN through the NIC specified by <interface> or <MAC> or EDD settings. For the second argument, currently only nodcb is supported. This parameter can be specified multiple times. Note: letters in the MAC-address must be lowercase!

  NBD

root=??? netroot=nbd:<server>:<port>[:<fstype>[:<mountopts>[:<nbdopts>]]]
    mount nbd share from <server>

root=dhcp with dhcp root-path=nbd:<server>:<port>[:<fstype>[:<mountopts>[:<nbdopts>]]]
    root=dhcp alone directs initrd to look at the DHCP root-path where NBD options can be specified. This syntax is only usable in cases where you are directly mounting the volume as the rootfs.

  DASD

rd.dasd=....
    same syntax as the kernel module parameter (s390 only)

  ZFCP

rd.zfcp=<zfcp adaptor device bus ID>,<WWPN>,<FCPLUN>
    rd.zfcp can be specified multiple times on the kernel command line. e.g.:

        rd.zfcp=0.0.4000,0x5005076300C213e9,0x5022000000000000

rd.zfcp.conf=0
    ignore zfcp.conf included in the initramfs

  ZNET

rd.znet=<nettype>,<subchannels>,<options>
    rd.znet can be specified multiple times on the kernel command line. e.g.:

        rd.znet=qeth,0.0.0600,0.0.0601,0.0.0602,layer2=1,portname=foo
        rd.znet=ctc,0.0.0600,0.0.0601,0.0.0602,protocol=bar

  Plymouth Boot Splash

plymouth.enable=0
    disable the plymouth bootsplash completly.

rd.plymouth=0
    disable the plymouth bootsplash only for the initramfs.

  Kernel keys

masterkey=<kernel master key path name>
    Set the path name of the kernel master key. e.g.:

        masterkey=/etc/keys/kmk-trusted.blob

masterkeytype=<kernel master key type>
    Set the type of the kernel master key. e.g.:

        masterkeytype=trusted

evmkey=<EVM key path name>
    Set the path name of the EVM key. e.g.:

        evmkey=/etc/keys/evm-trusted.blob

ecryptfskey=<eCryptfs key path name>
    Set the path name of the eCryptfs key. e.g.:

        ecryptfskey=/etc/keys/ecryptfs-trusted.blob

  Deprecated, renamed Options

Here is a list of options, which were used in dracut prior to version 008, and their new replacement.

rdbreak
    rd.break

rd_CCW
    rd.ccw

rd_DASD_MOD
    rd.dasd

rd_DASD
    rd.dasd

rdinitdebug rdnetdebug
    rd.debug

rd_NO_DM
    rd.dm=0

rd_DM_UUID
    rd.dm.uuid

rdblacklist
    rd.driver.blacklist

rdinsmodpost
    rd.driver.post

rdloaddriver
    rd.driver.pre

rd_NO_FSTAB
    rd.fstab=0

rdinfo
    rd.info

check
    rd.live.check

rdlivedebug
    rd.live.debug

live_dir
    rd.live.dir

liveimg
    rd.live.image

overlay
    rd.live.overlay

readonly_overlay
    rd.live.overlay.readonly

reset_overlay
    rd.live.overlay.reset

live_ram
    rd.live.ram

rd_NO_CRYPTTAB
    rd.luks.crypttab=0

rd_LUKS_KEYDEV_UUID
    rd.luks.keydev.uuid

rd_LUKS_KEYPATH
    rd.luks.keypath

rd_NO_LUKS
    rd.luks=0

rd_LUKS_UUID
    rd.luks.uuid

rd_NO_LVMCONF
    rd.lvm.conf

rd_LVM_LV
    rd.lvm.lv

rd_NO_LVM
    rd.lvm=0

rd_LVM_SNAPSHOT
    rd.lvm.snapshot

rd_LVM_SNAPSIZE
    rd.lvm.snapsize

rd_LVM_VG
    rd.lvm.vg

rd_NO_MDADMCONF
    rd.md.conf=0

rd_NO_MDIMSM
    rd.md.imsm=0

rd_NO_MD
    rd.md=0

rd_MD_UUID
    rd.md.uuid

rd_NFS_DOMAIN
    rd.nfs.domain

iscsi_initiator
    rd.iscsi.initiator

iscsi_target_name
    rd.iscsi.target.name

iscsi_target_ip
    rd.iscsi.target.ip

iscsi_target_port
    rd.iscsi.target.port

iscsi_target_group
    rd.iscsi.target.group

iscsi_username
    rd.iscsi.username

iscsi_password
    rd.iscsi.password

iscsi_in_username
    rd.iscsi.in.username

iscsi_in_password
    rd.iscsi.in.password

iscsi_firmware
    rd.iscsi.firmware=0

rd_NO_PLYMOUTH
    rd.plymouth=0

rd_retry
    rd.retry

rdshell
    rd.shell

rd_NO_SPLASH
    rd.splash

rdudevdebug
    rd.udev.debug

rdudevinfo
    rd.udev.info

rd_NO_ZFCPCONF
    rd.zfcp.conf=0

rd_ZFCP
    rd.zfcp

rd_ZNET
    rd.znet

KEYMAP
    vconsole.keymap

KEYTABLE
    vconsole.keymap

SYSFONT
    vconsole.font

CONTRANS
    vconsole.font.map

UNIMAP
    vconsole.font.unimap

UNICODE
    vconsole.unicode

EXT_KEYMAP
    vconsole.keymap.ext

  Configuration in the Initramfs

/etc/conf.d/
    Any files found in /etc/conf.d/ will be sourced in the initramfs to set initial values. Command line options will override these values set in the configuration files.

/etc/cmdline
    Can contain additional command line options.

/etc/cmdline.d/*.conf
    Can contain additional command line options.

AUTHOR

Harald Hoyer
    Project Leader and Developer

SEE ALSO

dracut(8) dracut.conf(5)

NOTES

1.  rfc4173
    http://tools.ietf.org/html/rfc4173#section-5