DRACUT

Section: Maintenance Commands (8)
Updated: June 2009
Index Return to Main Contents

NAME

dracut - create initial ramdisk images for preloading modules

SYNOPSIS

dracut [OPTION]... <image> <kernel-version>

DESCRIPTION

dracut creates an initial image used by the kernel for preloading the block device modules (such as IDE, SCSI or RAID) which are needed to access the root filesystem.

Options

-f, --force

overwrite existing initramfs file.

-m, --modules LIST

specify a space-separated list of dracut modules to call when building the initramfs. Modules are located in /usr/share/dracut/modules.d.

-o, --omit LIST

omit a space-separated list of dracut modules.

-a, --add LIST

add a space-separated list of dracut modules.

-d, --drivers LIST

specify a space-separated list of kernel modules to exclusively include in the initramfs. The kernel modules have to be specified without the ".ko" suffix.

--add-drivers LIST

specify a space-separated list of kernel modules to add to the initramfs. The kernel modules have to be specified without the ".ko" suffix.

--omit-drivers LIST

specify a space-separated list of kernel modules to omit from the initramfs. The kernel modules have to be specified without the ".ko" suffix. Regular expressions are also allowed like ".*/fs/ocfs/.*".

If [LIST] has multiple arguments, then you have to put these in quotes.

example: # dracut --omit "module1 module2" ...

--filesystems LIST

specify a space-separated list of kernel filesystem modules to exclusively include in the generic initramfs.

-k, --kmoddir {DIR}

specify the directory, where to look for kernel modules

--fwdir {DIR}

specify additional directory, where to look for firmwares

--kernel-only

only install kernel drivers and firmware files

--no-kernel

do not install kernel drivers and firmware files

--mdadmconf

include local /etc/mdadm.conf

--nomdadmconf

do not include local /etc/mdadm.conf

--strip

strip binaries in the initramfs (default)

--nostrip

do not strip binaries in the initramfs

-h, --help

display help text and exit.

--debug

output debug information of the build process

-v, --verbose

verbose output during the build process

-c, --conf FILE

specify configuration file to use. Default: /etc/dracut.conf

--confdir DIR

specify configuration directory to use. Default: /etc/dracut.conf.d

-l, --local

local mode. Use modules from the current working directory instead of the system-wide installed in /usr/share/dracut/modules.d. Useful when running dracut from a git checkout.

-H, --hostonly

Host-Only mode: Install only what is needed for booting the local host instead of a generic host.

-i, --include SOURCE TARGET

include the files in the SOURCE directory into the target directory in the final initramfs.

-I, --install LIST

install the space separated list of files into the initramfs.

KERNEL COMMAND LINE

The root filesystem used by the kernel is specified in the boot configuration file, as always. The traditional root=/dev/hda1 style device specification is allowed. If a label is used, as in root=LABEL=rootPart the initrd will search all available devices for an ext2 or ext3 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.

Standard

init=<path to real init>
root=<path to blockdevice>: specify blockdevice to use as root filesystem.
e.g.
root=/dev/sda1
root=/dev/disk/by-path/pci-0000:00:1f.1-scsi-0:0:1:0-part1
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_NO_FSTAB: do not honor special mount options for the root filesystem found in /etc/fstab of the real root.

Misc

rdblacklist=<drivername>: do not load kernel module <drivername> This parameter can be specified multiple times.
rdloaddriver=<drivername>: force loading kernel module <drivername> This parameter can be specified multiple times.

Debug

rdinfo: print informational output though "quiet" is set
rdshell: allow dropping to a shell, if root mounting fails
rdinitdebug: set -x for the dracut shell and logs to dmesg, console and /init.log
rdbreak: drop to a shell at the end
: rdbreak={cmdline:|pre-udev:|pre-trigger:|initqueue:|pre-mount:|mount:|pre-pivot} drop to a shell on defined breakpoint
rdudevinfo: set udev to loglevel info
rdudevdebug: set udev to loglevel debug

I18N

e.g.
  LANG=en_US.UTF-8
  SYSFONT=latarcyrheb-sun16
  KEYTABLE=de-latin1-nodeadkeys

KEYBOARDTYPE=sun|pc: will be written to /etc/sysconfig/keyboard in the initramfs
KEYTABLE=<keytable filename>: will be written to /etc/sysconfig/keyboard in the initramfs
SYSFONT=Console font: will be written to /etc/sysconfig/i18n in the initramfs
SYSFONTACM=Unicode font map: will be written to /etc/sysconfig/i18n in the initramfs
UNIMAP=Unicode font map: will be written to /etc/sysconfig/i18n in the initramfs
LANG=<locale>: will be written to /etc/sysconfig/i18n in the initramfs

LVM

rd_NO_LVM: 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_NO_LVMCONF: remove any /etc/lvm/lvm.conf, which may exist in the initramfs

crypto LUKS

rd_NO_LUKS: 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_NO_CRYPTTAB: do not check, if LUKS partition is in /etc/crypttab

MD

rd_NO_MD: disable MD RAID detection
rd_NO_MDIMSM: no MD RAID for imsm/isw raids, use dmraid instead
rd_NO_MDADMCONF: ignore mdadm.conf included in initramfs
rd_MD_UUID=<md uuid>: only activate the raid sets with the given UUID. This parameter can be specified multiple times.

DMRAID

rd_NO_DM: disable DM RAID detection
rd_DM_UUID=<dmraid uuid>: only activate the raid sets with the given UUID. This parameter can be specified multiple times.

FIPS

fips=1

enable FIPS

boot=<bootdevice>

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>

If the root device is encrypted, the /boot partition must reside on a seperate partition and has to be specified.

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}

dhcp|on|any|dhcp6: get ip from dhcp server on a specific interface auto6: do IPv6 autoconfiguration This parameter can be specified multiple times.

ip=<client-IP>::[<server-id>]::<gateway-IP>::<netmask>::<clienthostname>::<interface>::{none|off} 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.

ifname=<interface>:<MAC>

Assign network device name <interface> (ie eth0) to the NIC with MAC <MAC>. Note letters in the MAC-address must be lowercase! Note that 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|1]}

turn off/on biosdevname network interface renaming

NFS

root=[<server-ip>:]<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:[<server-ip>:]<root-dir>[:<nfs-options>]
root=nfs4:[<server-ip>:]<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=[<server-ip>:]<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 (Section 7). 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.

http://tools.ietf.org/html/rfc4173

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=??? iscsi_initiator=<initiator> iscsi_target_name=<target name> iscsi_target_ip=<target ip> iscsi_target_port=<target port> iscsi_target_group=<target group> iscsi_username=<username> iscsi_password=<password> iscsi_in_username=<in username> iscsi_in_password=<in password> manually specify all iscsistart parameter (see iscsistart --help)

root=??? netroot=iscsi iscsi_firmware

will read the iscsi parameter from the BIOS firmware

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 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. Note letters in the MAC-address must be lowercase! This parameter can be specified multiple times.

NBD

root=nbd:<server>:<port>[:<fstype>][:<mountopts>]

mount nbd share from <server>

root=dhcp

with dhcp root-path=nbd:<server>:<port>[:<fstype>][:<mountopts>] 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_MOD=....: same syntax as the kernel module parameter (s390 only)
: rd_DASD=<dasd adaptor device bus ID>:[,readonly=X]:[,use_diag=X]:[,erplog=X]:[,failfast=X] activate DASD device with the given adaptor device bus ID and setting the sysfs attributes to the specified values This parameter can be specified multiple times.

ZFCP

rd_ZFCP=<zfcp adaptor device bus ID>,:<WWPN>,:<FCPLUN>: rd_ZFCP can be specified multiple times on the kernel command line.
example: rd_ZFCP=0.0.4000,0x5005076300C213e9,0x5022000000000000
rd_NO_ZFCPCONF: 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. Examples:
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

rd_NO_PLYMOUTH: do not start plymouth. This will not work with encrypted partitions.

FILES

/var/log/dracut.log
/etc/dracut.conf: see dracut.conf(5)

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.

AUTHORS

Harald Hoyer <harald@redhat.com>
Victor Lowther <victor.lowther@gmail.com>
Warren Togami <wtogami@redhat.com>
Jeremy Katz <katzj@redhat.com>
Philippe Seewer <philippe.seewer@bfh.ch>
David Dillow <dave@thedillows.org>

AVAILABILITY

The dracut command is part of the dracut package and is available from http://sourceforge.net/apps/trac/dracut/wiki

Index

NAME

SYNOPSIS

DESCRIPTION

Options

KERNEL COMMAND LINE

Standard
Misc
Debug
I18N
LVM
crypto LUKS
MD
DMRAID
FIPS
Network
NFS
iSCSI
FCoE
NBD
DASD
ZFCP
ZNET
Plymouth Boot Splash

FILES

Configuration in the Initramfs

AUTHORS

AVAILABILITY

SEE ALSO

This document was created by man2html, using the manual pages.
Time: 05:34:25 GMT, December 24, 2015