Dracut/Options

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Contents

Options

SYNOPSIS

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

-f, --force

-f, --force
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Overwrite existing initramfs file.

-m, --modules

-m, --modules LIST
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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

-o, --omit LIST
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Omit a space-separated list of dracut modules.

-a, --add

-a, --add LIST
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Add a space-separated list of dracut modules.

-d, --drivers

-d, --drivers LIST
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Specify a space-separated list of kernel modules to include in the initramfs.

-h, --help

-h, --help
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Display help text and exit.

--debug

--debug
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Output debug information of the build process

v, --verbose

v, --verbose
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Verbose output during the build process

-c, --conf

-c, --conf FILE
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Specify configuration file to use. Default: /etc/dracut.conf

-l, --local

-l, --local
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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

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

-i, --include

-i, --include SOURCE TARGET
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Include the files in the SOURCE directory into the target directory in the final initramfs.

-I, --install

</pre>-I, --install LIST</pre>

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Install the space separated list of files into the initramfs.

Dracut kernel command line parameters

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.

Limitations

  • Command line length: 2048
  • dhcp root-path: 255



Standard

init=<path to real init>
root=<path to blockdevice>
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Specify e.g. /dev/sda1 or /dev/disk/by-path/pci-0000:00:1f.1-scsi-0:0:1:0-part1

I18N

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

<preLANG=<locale></pre>

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Will be written to /etc/sysconfig/i18n in the initramfs

DHCP

root=dhcp
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Get IP from dhcp server, root-path option from dhcp specifies root location.

NFSv3

root=[<server-ip>:]<root-dir>[:<nfs-options>]
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Mount nfs share from <server-ip>:/<root-dir> If no server-ip is given use dhcp next_server. nfs-options can be appended with the prefix ":" or ","
root=dhcp
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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>]

Deprecated

root=/dev/nfs nfsroot=[<server-ip>:]<root-dir>[,<nfs-options>]
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Kernel Documentation/filesystems/nfsroot.txt defines this method. This is supported by dracut but not recommended.

NFSv4

root=nfs4:[<server-ip>:]<root-dir>[:<nfs-options>]
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mount nfsv4 share from <server-ip>:/<root-dir>. If no server-ip is given, use dhcp next_server. nfs-options can be appended with the prefix ":" or ","
root=dhcp
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root-path=nfs4:<server-ip>:<root-dir>[,<nfs-options>]. root=dhcp alone directs initrd to look at the DHCP root-path where NFS options can be specified.

iSCSI

root=iscsi:[<servername>]:[<protocol>]:[<port>]:[<LUN>]:<targetname>::
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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.RFC4173
root=??? iscsiroot=...::
root=??? iscsi_initiator= iscsi_target_name= iscsi_target_ip= iscsi_target_port= iscsi_target_group= iscsi_username= iscsi_password= iscsi_in_username= iscsi_in_password=::
root=??? iscsi_firmware::

NBD

root=nbd:<server>:<port>[:<fstype>][:<mountopts>]
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Mount nbd share from <server>.
root=dhcp
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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.

Network

ip=[dhcp|on|any]
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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.
ip=<interface>:[dhcp|on|any]
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Get ip from dhcp server on a specific interface.
ip=<client-IP-number>:<gateway-IP-number>:<netmask>:<client-hostname>:<interface>:[dhcp|on|any|]
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Explicit network configuration

Misc

rdblacklist=<modulename>
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TBD: do not load modulename.

Debug

rdinitdebug
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Drop to a shell, if the imitramfs fails.
rdinitdebug
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set -x for the dracut shell.
rdbreak=[pre-udev|pre-mount|mount|pre-pivot|]
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Drop the shell on defined breakpoint.
rdudevinfo
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Set udev to loglevel info.
rdudevdebug
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Set udev to loglevel debug.
rdnetdebug
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Debug network scripts in dracut.

Configuration in initrd

/conf/conf.d/* 
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Command line options can override values set here