NAME
dracut.cmdline - dracut kernel command line optionsDESCRIPTION
The root device used by the kernel is specified in the boot configuration file on the kernel command line, as always.Standard
init=<path to real init>specify the path to the init program to be
started after the initramfs has finished
root=<path to blockdevice>
specify the block device to use as the root
filesystem.
Example.
rootfstype=<filesystem type>
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 root=PARTUUID=3f5ad593-4546-4a94-a374-bcfb68aa11f7
"auto" if not specified.
Example.
rootflags=<mount options>
rootfstype=ext3
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.
ro
force mounting / and /usr (if it
is a separate device) read-only. If none of ro and rw is present, both are
mounted according to /etc/fstab.
rw
force mounting / and /usr (if it
is a separate device) read-write. See also ro option.
rootfallback=<path to blockdevice>
specify the block device to use as the root
filesystem, if the normal root cannot be found. This can only be a simple
block device with a simple file system, for which the filesystem driver is
either compiled in, or added manually to the initramfs. This parameter can be
specified multiple times.
rd.auto rd.auto=1
enable autoassembly of special devices like
cryptoLUKS, dmraid, mdraid or lvm. Default is off as of dracut version >=
024.
rd.hostonly=0
removes all compiled in configuration of the
host system the initramfs image was built on. This helps booting, if any disk
layout changed, especially in combination with rd.auto or other parameters
specifying the layout.
rd.cmdline=ask
prompts the user for additional kernel command
line parameters
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>
resume from a swap partition
Example.
rd.skipfsck
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
skip fsck for rootfs and /usr. If
you’re mounting /usr read-only and the init system performs fsck
before remount, you might want to use this option to avoid duplication.
iso-scan/filename
Mount all mountable devices and search for ISO pointed by the argument. When the ISO is found set it up as a loop device. Device containing this ISO image will stay mounted at /run/initramfs/isoscandev. Using iso-scan/filename with a Fedora/Red Hat/CentOS Live iso should just work by copying the original kernel cmdline parameters. Example.menuentry 'Live Fedora 20' --class fedora --class gnu-linux --class gnu --class os { set isolabel=Fedora-Live-LXDE-x86_64-20-1 set isofile="/boot/iso/Fedora-Live-LXDE-x86_64-20-1.iso" loopback loop $isofile linux (loop)/isolinux/vmlinuz0 boot=isolinux iso-scan/filename=$isofile root=live:LABEL=$isolabel ro rd.live.image quiet rhgb initrd (loop)/isolinux/initrd0.img }
Misc
rd.emergency=[reboot|poweroff|halt]specify, what action to execute in case of a
critical failure. rd.shell=0 must also be specified.
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.
rd.retry=<seconds>
specify how long dracut should retry the
initqueue to configure devices. The default is 180 seconds. After 2/3 of the
time, degraded raids are force started. If you have hardware, which takes a
very long time to announce its drives, you might want to extend this
value.
rd.timeout=<seconds>
specify how long dracut should wait for
devices to appear. The default is 0, which means forever. Note
that this timeout should be longer than rd.retry to allow for proper
configuration.
rd.noverifyssl
accept self-signed certificates for ssl
downloads.
rd.ctty=<terminal device>
specify the controlling terminal for the
console. This is useful, if you have multiple "console="
arguments.
rd.shutdown.timeout.umount=<seconds>
specify how long dracut should wait for an
individual umount to finish during shutdown. This avoids the system from
blocking when unmounting a file system cannot complete and waits indefinitely.
Value 0 means to wait forever. The default is 90 seconds.
Debug
If you are dropped to an emergency shell, the file /run/initramfs/rdsosreport.txt is created, which can be saved to a (to be mounted by hand) partition (usually /boot) or a USB stick. Additional debugging info can be produced by adding rd.debug to the kernel command line. /run/initramfs/rdsosreport.txt contains all logs and the output of some tools. It should be attached to any report about dracut problems. rd.infoprint 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. If systemd is
active in the initramfs, all output is logged to the systemd journal, which
you can inspect with "journalctl -ab". If systemd is not active, the
logs are written to dmesg and /run/initramfs/init.log. If
"quiet" is set, it also logs to the console.
rd.memdebug=[0-5]
Print memory usage info at various points, set
the verbose level from 0 to 5.
rd.break
Higher level means more debugging output:
0 - no output 1 - partial /proc/meminfo 2 - /proc/meminfo 3 - /proc/meminfo + /proc/slabinfo 4 - /proc/meminfo + /proc/slabinfo + memstrack summary NOTE: memstrack is a memory tracing tool that tracks the total memory consumption, and peak memory consumption of each kernel modules and userspace progress during the whole initramfs runtime, report is genereted and the end of initramsfs run. 5 - /proc/meminfo + /proc/slabinfo + memstrack (with top memory stacktrace) NOTE: memstrack (with top memory stacktrace) will print top memory allocation stack traces during the whole initramfs runtime.
drop to a shell at the end
rd.break={cmdline|pre-udev|pre-trigger|initqueue|pre-mount|mount|pre-pivot|cleanup}
drop to a shell before the defined breakpoint
starts
rd.udev.info
set udev to loglevel info
rd.udev.debug
set udev to loglevel debug
I18N
rd.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.
Example.
rd.vconsole.keymap.ext=<list of keymap base file names>
rd.vconsole.keymap=de-latin1-nodeadkeys
list of extra keymaps to bo loaded (sep. by
space); will be written as EXT_KEYMAP to /etc/vconsole.conf in the
initramfs
rd.vconsole.unicode
boolean, indicating UTF-8 mode; will be
written as UNICODE to /etc/vconsole.conf in the initramfs
rd.vconsole.font=<font base file name>
console font; taken from consolefonts
directory; will be written as FONT to /etc/vconsole.conf in the
initramfs.
Example.
rd.vconsole.font.map=<console map base file name>
rd.vconsole.font=eurlatgr
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
rd.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
rd.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.
Example.
rd.locale.LC_ALL=<locale>
rd.locale.LANG=pl_PL.utf8
taken from the environment; will be written as
LC_ALL to /etc/locale.conf in the initramfs
LVM
rd.lvm=0disable LVM detection
rd.lvm.vg=<volume group name>
only activate all logical volumes in the the
volume groups with the given name. rd.lvm.vg can be specified multiple times
on the kernel command line.
rd.lvm.lv=<volume group name>/<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=0disable 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.
<luks uuid> may be prefixed by the keyword keysource:, see
rd.luks.key below.
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
rd.luks.timeout=<seconds>
specify how long dracut should wait when
waiting for the user to enter the password. This avoid blocking the boot if no
password is entered. It does not apply to luks key. The default is 0,
which means forever.
crypto LUKS - key on removable device support
NB: If systemd is included in the dracut initrd, dracut’s built in removable device keying support won’t work. systemd will prompt for a password from the console even if you’ve supplied rd.luks.key. You may be able to use standard systemd fstab(5) syntax to get the same effect. If you do need rd.luks.key to work, you will have to exclude the "systemd" dracut module and any modules that depend on it. See dracut.conf(5) and https://bugzilla.redhat.com/show_bug.cgi?id=905683 for more information. rd.luks.key=<keypath>[:<keydev>[:<luksdev>]]
<keypath> is the pathname of a
key file, relative to the root of the filesystem on some device. It’s
REQUIRED. When <keypath> ends with .gpg it’s
considered to be key encrypted symmetrically with GPG. You will be prompted
for the GPG password on boot. GPG support comes with the crypt-gpg
module, which needs to be added explicitly.
<keydev> identifies the device on which the key file resides. It
may be the kernel name of the device (should start with "/dev/"), a
UUID (prefixed with "UUID=") or a label (prefix with
"LABEL="). You don’t have to specify a 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 it’s not
present, all block devices will be probed, which may significantly increase
boot time.
If <luksdev> is given, the specified key will only be used for the
specified 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:
Example.
As you see, you can skip colons in such a case.
rd.luks.key=/foo/bar.key
gpg --quiet --decrypt rootkey.gpg | \ cryptsetup --batch-mode --key-file - \ luksFormat /dev/sda47
head -32c /dev/urandom > rootkey.key cryptsetup --batch-mode --key-file rootkey.key \ luksFormat /dev/sda47
•you can unlock your disk(s) using
multiple passphrases
•better security by not loosing the key
stretching mechanism
rd.luks.uuid=aaaa rd.luks.uuid=bbbb rd.luks.uuid=keysource:cccc rd.luks.key=/keyfile:UUID=CCCC
specify how many times dracut will try to read
the keys specified in in rd.luk.key. This gives a chance to the removable
device containing the key to initialise.
MD RAID
rd.md=0disable 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=0disable 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.
MULTIPATH
rd.multipath=0disable multipath detection
rd.multipath=default
use default multipath settings
FIPS
rd.fipsenable FIPS
boot=<boot device>
specify the device, where /boot is located.
Example.
rd.fips.skipkernel
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>
skip checksum check of the kernel image.
Useful, if the kernel image is not in a separate boot partition.
Network
•firmware/bios-provided index numbers
for on-board devices
•firmware-provided pci-express hotplug
slot index number
•physical/geographical location of the
hardware
•the interface’s MAC
address
ethernet
wl
wlan
ww
wwan
on-board device index number
s<slot>[f<function>][d<dev_id>]
hotplug slot index number
x<MAC>
MAC address
[P<domain>]p<bus>s<slot>[f<function>][d<dev_id>]
PCI geographical location
[P<domain>]p<bus>s<slot>[f<function>][u<port>][..][c<config>][i<interface>]
USB port number chain
•eno1
•ens1
•enp2s0f0
•enp2s0f1
•wlp3s0
•wwp0s29u1u4i6
•enp0s29u1u2
dhcp|on|any
ip=<interface>:{dhcp|on|any|dhcp6|auto6|link6}[:[<mtu>][:<macaddr>]]
get ip from dhcp server from all interfaces.
If netroot=dhcp, loop sequentially through all interfaces (eth0, eth1, ...)
and use the first with a valid DHCP root-path.
single-dhcp
Send DHCP on all available interfaces in
parallel, as opposed to one after another. After the first DHCP response is
received, stop DHCP on all other interfaces. This gives the fastest boot time
by using the IP on interface for which DHCP succeeded first during early boot.
Caveat: Does not apply to Network Manager and to SUSE using wicked.
auto6
IPv6 autoconfiguration
dhcp6
IPv6 DHCP
either6
if auto6 fails, then dhcp6
link6
bring up interface for IPv6 link-local
addressing
This parameter can be specified multiple
times.
dhcp|on|any|dhcp6
ip=<client-IP>:[<peer>]:<gateway-IP>:<netmask>:<client_hostname>:<interface>:{none|off|dhcp|on|any|dhcp6|auto6|ibft}[:[<mtu>][:<macaddr>]]
get ip from dhcp server on a specific
interface
auto6
do IPv6 autoconfiguration
link6
bring up interface for IPv6 link local
address
<macaddr>
optionally set <macaddr> on the
<interface>. This cannot be used in conjunction with the ifname
argument for the same <interface>.
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. <peer> is optional and is the
address of the remote endpoint for pointopoint interfaces and it may be
followed by a slash and a decimal number, encoding the network prefix length.
<macaddr>
ip=<client-IP>:[<peer>]:<gateway-IP>:<netmask>:<client_hostname>:<interface>:{none|off|dhcp|on|any|dhcp6|auto6|ibft}[:[<dns1>][:<dns2>]]
optionally set <macaddr> on the
<interface>. This cannot be used in conjunction with the ifname
argument for the same <interface>.
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. <peer> is optional and is the
address of the remote endpoint for pointopoint interfaces and it may be
followed by a slash and a decimal number, encoding the network prefix
length.
ifname=<interface>:<MAC>
Assign network device name <interface>
(i.e. "bootnet") to the NIC with MAC <MAC>.
Warning
Do not use the default kernel naming scheme for the interface name, as it
can conflict with the kernel names. So, don’t use "eth[0-9]+"
for the interface name. Better name it "bootnet" or
"bluesocket".
rd.route=<net>/<netmask>:<gateway>[:<interface>]
Add a static route with route options, which
are separated by a colon. IPv6 addresses have to be put in brackets.
Example.
bootdev=<interface>
rd.route=192.168.200.0/24:192.168.100.222:ens10 rd.route=192.168.200.0/24:192.168.100.222 rd.route=192.168.200.0/24::ens10 rd.route=[2001:DB8:3::/8]:[2001:DB8:2::1]:ens10
specify network interface to use routing and
netroot information from. Required if multiple ip= lines are used.
BOOTIF=<MAC>
specify network interface to use routing and
netroot information from.
rd.bootif=0
Disable BOOTIF parsing, which is provided by
PXE
nameserver=<IP> [nameserver=<IP> ...]
specify nameserver(s) to use
rd.peerdns=0
Disable DNS setting of DHCP parameters.
biosdevname=0
boolean, turn off biosdevname network
interface renaming
rd.neednet=1
boolean, bring up network even without netroot
set
vlan=<vlanname>:<phydevice>
Setup vlan device named <vlanname> on
<phydevice>. We support the four styles of vlan names: VLAN_PLUS_VID
(vlan0005), VLAN_PLUS_VID_NO_PAD (vlan5), DEV_PLUS_VID (eth0.0005),
DEV_PLUS_VID_NO_PAD (eth0.5)
bond=<bondname>[:<bondslaves>:[:<options>[:<mtu>]]]
Setup bonding device <bondname> on top
of <bondslaves>. <bondslaves> is a comma-separated list of
physical (ethernet) interfaces. <options> is a comma-separated list on
bonding options (modinfo bonding for details) in format compatible with
initscripts. If <options> includes multi-valued arp_ip_target option,
then its values should be separated by semicolon. if the mtu is specified, it
will be set on the bond master. Bond without parameters assumes
bond=bond0:eth0,eth1:mode=balance-rr
team=<teammaster>:<teamslaves>[:<teamrunner>]
Setup team device <teammaster> on top of
<teamslaves>. <teamslaves> is a comma-separated list of physical
(ethernet) interfaces. <teamrunner> is the runner type to be used (see
teamd.conf(5)); defaults to activebackup. Team without parameters
assumes team=team0:eth0,eth1:activebackup
bridge=<bridgename>:<ethnames>
Setup bridge <bridgename> with
<ethnames>. <ethnames> is a comma-separated list of physical
(ethernet) interfaces. Bridge without parameters assumes bridge=br0:eth0
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 separated by ",".
root=nfs:[<server-ip>:]<root-dir>[:<nfs-options>],
root=nfs4:[<server-ip>:]<root-dir>[:<nfs-options>],
root={dhcp|dhcp6}
netroot=dhcp alone directs initrd to look at
the DHCP root-path where NFS options can be specified.
Example.
root=/dev/nfs
nfsroot=[<server-ip>:]<root-dir>[:
<nfs-options>]
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>]
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 override the
settings in /etc/idmap.conf.
rd.net.dhcp.retry=<cnt>
If this option is set, dracut will try to
connect via dhcp <cnt> times before failing. Default is 1.
rd.net.timeout.dhcp=<arg>
If this option is set, dhclient is called with
"--timeout <arg>".
rd.net.timeout.iflink=<seconds>
Wait <seconds> until link shows up.
Default is 60 seconds.
rd.net.timeout.ifup=<seconds>
Wait <seconds> until link has state
"UP". Default is 20 seconds.
rd.net.timeout.route=<seconds>
Wait <seconds> until route shows up.
Default is 20 seconds.
rd.net.timeout.ipv6dad=<seconds>
Wait <seconds> until IPv6 DAD is
finished. Default is 50 seconds.
rd.net.timeout.ipv6auto=<seconds>
Wait <seconds> until IPv6 automatic
addresses are assigned. Default is 40 seconds.
rd.net.timeout.carrier=<seconds>
Wait <seconds> until carrier is
recognized. Default is 10 seconds.
CIFS
root=cifs://[<username>[:<password>]@]<server-ip>:<root-dir>mount cifs 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]. If a username or password are not specified as part of the
root, then they must be passed on the command line through cifsuser/cifspass.
Warning
Passwords specified on the kernel command line are visible for all users via the
file /proc/cmdline and via dmesg or can be sniffed on the network, when
using DHCP with DHCP root-path.
cifsuser=<username>
Set the cifs username, if not specified as
part of the root.
cifspass=<password>
Set the cifs password, if not specified as
part of the root.
Warning
Passwords specified on the kernel command line are visible for all users via the
file /proc/cmdline and via dmesg or can be sniffed on the network, when
using DHCP with DHCP root-path.
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].
Warning
Passwords specified on the kernel command line are visible for all users via the
file /proc/cmdline and via dmesg or can be sniffed on the network, when
using DHCP with DHCP root-path.
Example.
If servername is an IPv6 address, it has to be put in brackets:
Example.
root=???
netroot=iscsi:[<username>:<password>[:
<reverse>:
<password>]@][<servername>]:[
<protocol>]:[
<port>][:[<iscsi_iface_name>]:[
<netdev_name>]]:[ <LUN>]:<targetname>
...
root=iscsi:192.168.50.1::::iqn.2009-06.dracut:target0
root=iscsi:[2001:DB8::1]::::iqn.2009-06.dracut:target0
multiple netroot options allow setting up
multiple iscsi disks:
Example.
If servername is an IPv6 address, it has to be put in brackets:
Example.
Warning
Passwords specified on the kernel command line are visible for all users via the
file /proc/cmdline and via dmesg or can be sniffed on the network, when
using DHCP with DHCP root-path. You may want to use rd.iscsi.firmware.
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>
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
netroot=iscsi:[2001:DB8::1]::::iqn.2009-06.dracut:target0
manually specify all iscsistart parameter (see
iscsistart --help)
Warning
Passwords specified on the kernel command line are visible for all users via the
file /proc/cmdline and via dmesg or can be sniffed on the network, when
using DHCP with DHCP root-path. You may want to use rd.iscsi.firmware.
root=??? netroot=iscsi rd.iscsi.firmware=1
will read the iscsi parameter from the BIOS
firmware
rd.iscsi.login_retry_max=<num>
maximum number of login retries
rd.iscsi.param=<param>
<param> will be passed as "--param
<param>" to iscsistart. This parameter can be specified multiple
times.
Example.
will result in
"netroot=iscsi rd.iscsi.firmware=1 rd.iscsi.param=node.session.timeo.replacement_timeout=30"
iscsistart -b --param node.session.timeo.replacement_timeout=30
FCoE
rd.fcoe=0disable FCoE and lldpad
fcoe=<edd|interface|MAC>:{dcb|nodcb}:{fabric|vn2vn}
Try to connect to a FCoE SAN through the NIC
specified by <interface> or <MAC> or EDD settings.
The second argument specifies if DCB should be used. The optional third
argument specifies whether fabric or VN2VN mode should be used. This parameter
can be specified multiple times.
Note
letters in the MAC-address must be lowercase!
NVMf
rd.nonvmfDisable NVMf
rd.nvmf.hostnqn=<hostNQN>
NVMe host NQN to use
rd.nvmf.hostid=<hostID>
NVMe host id to use
rd.nvmf.discover={rdma|fc|tcp},<traddr>,[<host_traddr>],[<trsvcid>]
Discover and connect to a NVMe-over-Fabric
controller specified by <traddr> and the optionally
<host_traddr> or <trsvcid>. The first argument
specifies the transport to use; currently only rdma, fc, or
tcp are supported. This parameter can be specified multiple times.
Examples.
rd.nvmf.discover=fc,auto
rd.nvmf.discover=tcp,192.168.10.10,,4420 rd.nvmf.discover=fc,nn-0x201700a05634f5bf:pn-0x201900a05634f5bf,nn-0x200000109b579ef3:pn-0x100000109b579ef3
This special syntax determines that Fibre
Channel autodiscovery is to be used rather than regular NVMe discovery. It
takes precedence over all other rd.nvmf.discover= arguments.
NBD
root=??? netroot=nbd:<server>:<port/exportname>[: <fstype>[: <mountopts>[:<nbdopts>]]]mount nbd share from <server>.
NOTE: If "exportname" instead of "port" is given the
standard port is used. Newer versions of nbd are only supported with
"exportname".
root=/dev/root netroot=dhcp with dhcp
root-path=nbd:<server>:
<port/exportname>[:<fstype>[:<mountopts>[:<nbdopts>]]]
netroot=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.
NOTE: If "exportname" instead of "port" is given the
standard port is used. Newer versions of nbd are only supported with
"exportname".
VIRTIOFS
root=virtiofs:<mount-tag>mount virtiofs share using the tag
<mount-tag>. The tag name is arbitrary and must match the tag given in
the qemu -device command.
rootfstype=virtiofs root=<mount-tag>
mount virtiofs share using the tag
<mount-tag>. The tag name is arbitrary and must match the tag given in
the qemu -device command.
root=virtiofs:host rw
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.
rd.zfcp=<zfcp adaptor device bus ID>
If NPIV is enabled and the
allow_lun_scan parameter to the zfcp module is set to Y then the
zfcp adaptor will be initiating a scan internally and the <WWPN> and
<FCPLUN> parameters can be omitted.
Example.
rd.zfcp.conf=0
rd.zfcp=0.0.4000,0x5005076300C213e9,0x5022000000000000 rd.zfcp=0.0.4000
ignore zfcp.conf included in the
initramfs
ZNET
rd.znet=<nettype>,<subchannels>,<options>The whole parameter is appended to
/etc/ccw.conf, which is used on RHEL/Fedora with ccw_init, which is called
from udev for certain devices on z-series. rd.znet can be specified multiple
times on the kernel command line.
rd.znet_ifname=<ifname>:<subchannels>
Assign network device name <interface>
(i.e. "bootnet") to the NIC corresponds to the subchannels. This is
useful when dracut’s default "ifname=" doesn’t work
due to device having a changing MAC address.
Example.
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,protocol=bar
Booting live images
Dracut offers multiple options for live booted images: SquashFS with read-only filesystem imageThe system will boot with a read-only
filesystem from the SquashFS and apply a writable Device-mapper snapshot or an
OverlayFS overlay mount for the read-only base filesystem. This method ensures
a relatively fast boot and lower RAM usage. Users must be careful to
avoid writing too many blocks to a snapshot volume. Once the blocks of the
snapshot overlay are exhausted, the root filesystem becomes read-only and may
cause application failures. The snapshot overlay file is marked
Overflow, and a difficult recovery is required to repair and enlarge
the overlay offline. Non-persistent overlays are sparse files in RAM that only
consume content space as required blocks are allocated. They default to an
apparent size of 32 GiB in RAM. The size can be adjusted with the
rd.live.overlay.size= kernel command line option.
The filesystem structure is traditionally expected to be:
For OverlayFS mount overlays, the filesystem structure may also be a direct
compression of the root filesystem:
Dracut uses one of the overlay methods of live booting by default. No additional
command line options are required other than root=live:<URL> to
specify the location of your squashed filesystem.
Uncompressed live filesystem image
squashfs.img | SquashFS from LiveCD .iso !(mount) /LiveOS |- rootfs.img | Filesystem image to mount read-only !(mount) /bin | Live filesystem /boot | /dev | ... |
squashfs.img | SquashFS from LiveCD .iso !(mount) /bin | Live filesystem /boot | /dev | ... |
•The compressed SquashFS image can be
copied during boot to RAM at /run/initramfs/squashed.img by using the
rd.live.ram=1 option.
•A device with a persistent overlay can
be booted read-only by using the rd.live.overlay.readonly option on the
kernel command line. This will either cause a temporary, writable overlay to
be stacked over a read-only snapshot of the root filesystem or the OverlayFS
mount will use an additional lower layer with the root filesystem.
When the live system was installed with the
--skipcompress option of the livecd-iso-to-disk installation
script for Live USB devices, the root filesystem image, rootfs.img, is
expanded on installation and no SquashFS is involved during boot.
Writable filesystem image
•If rd.live.ram=1 is used in
this situation, the full, uncompressed root filesystem is copied during boot
to /run/initramfs/rootfs.img in the /run tmpfs.
•If rd.live.overlay=none is
provided as a kernel command line option, a writable, linear Device-mapper
target is created on boot with no overlay.
The system will retrieve a compressed
filesystem image, extract it to /run/initramfs/fsimg/rootfs.img, connect it to
a loop device, create a writable, linear Device-mapper target at
/dev/mapper/live-rw, and mount that as a writable volume at /. More RAM is
required during boot but the live filesystem is easier to manage if it becomes
full. Users can make a filesystem image of any size and that size will be
maintained when the system boots. There is no persistence of root filesystem
changes between boots with this option.
The filesystem structure is expected to be:
To use this boot option, ensure that rd.writable.fsimg=1 is in your
kernel command line and add the root=live:<URL> to specify the
location of your compressed filesystem image tarball or SquashFS image.
rd.writable.fsimg=1
rootfs.tgz | Compressed tarball containing filesystem image !(unpack) /rootfs.img | Filesystem image at /run/initramfs/fsimg/ !(mount) /bin | Live filesystem /boot | /dev | ... |
Enables writable filesystem support. The
system will boot with a fully writable (but non-persistent) filesystem without
snapshots (see notes above about available live boot options). You can
use the rootflags option to set mount options for the live filesystem
as well (see documentation about rootflags in the
Standard section above). This implies that the whole
image is copied to RAM before the boot continues.
Note
There must be enough free RAM available to hold the complete image.
This method is very suitable for diskless boots.
root=live:<url>
Boots a live image retrieved from
<url>. Requires the dracut livenet module. Valid handlers:
http, https, ftp, torrent, tftp.
Examples.
rd.live.debug=1
root=live:http://example.com/liveboot.img root=live:ftp://ftp.example.com/liveboot.img root=live:torrent://example.com/liveboot.img.torrent
Enables debug output from the live boot
process.
rd.live.dir=<path>
Specifies the directory within the boot device
where the squashfs.img or rootfs.img can be found. By default, this is
/LiveOS.
rd.live.squashimg=<filename of SquashFS image>
Specifies the filename for a SquashFS image of
the root filesystem. By default, this is squashfs.img.
rd.live.ram=1
Copy the complete image to RAM and use this
for booting. This is useful when the image resides on, e.g., a DVD which needs
to be ejected later on.
rd.live.overlay={<devspec>[:{<pathspec>|auto}]|none}
Manage the usage of a permanent overlay.
rd.live.overlay.cowfs=[btrfs|ext4|xfs]
•<devspec> specifies the
path to a device with a mountable filesystem.
•<pathspec> is the path to
a file within that filesystem, which shall be used to persist the changes made
to the device specified by the root=live:<url>
option.
The default pathspec, when auto or no :<pathspec> is
given, is /<rd.live.dir>/overlay-<label>-<uuid>, where
<label> is the device LABEL, and <uuid> is the
device UUID. * none (the word itself) specifies that no overlay will be
used, such as when an uncompressed, writable live root filesystem is
available.
If a persistent overlay is detected at the standard LiveOS path, the
overlay & overlay type detected, whether Device-mapper or OverlayFS, will
be used.
Examples.
rd.live.overlay=/dev/sdb1:persistent-overlay.img rd.live.overlay=UUID=99440c1f-8daa-41bf-b965-b7240a8996f4
Specifies the filesystem to use when
formatting the overlay partition. The default is ext4.
rd.live.overlay.size=<size_MiB>
Specifies a non-persistent Device-mapper
overlay size in MiB. The default is 32768.
rd.live.overlay.readonly=1
This is used to boot with a normally
read-write persistent overlay in a read-only mode. With this option, either an
additional, non-persistent, writable snapshot overlay will be stacked over a
read-only snapshot, /dev/mapper/live-ro, of the base filesystem with the
persistent overlay, or a read-only loop device, in the case of a writable
rootfs.img, or an OverlayFS mount will use the persistent overlay
directory linked at /run/overlayfs-r as an additional lower layer along with
the base root filesystem and apply a transient, writable upper directory
overlay, in order to complete the booted root filesystem.
rd.live.overlay.reset=1
Specifies that a persistent overlay should be
reset on boot. All previous root filesystem changes are vacated by this
action.
rd.live.overlay.thin=1
Enables the usage of thin snapshots instead of
classic dm snapshots. The advantage of thin snapshots is that they support
discards, and will free blocks that are not claimed by the filesystem. In this
use case, this means that memory is given back to the kernel when the
filesystem does not claim it anymore.
rd.live.overlay.overlayfs=1
Enables the use of the OverlayFS kernel
module, if available, to provide a copy-on-write union directory for the root
filesystem. OverlayFS overlays are directories of the files that have changed
on the read-only base (lower) filesystem. The root filesystem is provided
through a special overlay type mount that merges the lower and upper
directories. If an OverlayFS upper directory is not present on the boot
device, a tmpfs directory will be created at /run/overlayfs to provide
temporary storage. Persistent storage can be provided on vfat or msdos
formatted devices by supplying the OverlayFS upper directory within an
embedded filesystem that supports the creation of trusted.* extended
attributes and provides a valid d_type in readdir responses, such as with ext4
and xfs. On non-vfat-formatted devices, a persistent OverlayFS overlay can
extend the available root filesystem storage up to the capacity of the LiveOS
disk device.
If a persistent overlay is detected at the standard LiveOS path, the overlay
& overlay type detected, whether OverlayFS or Device-mapper, will be used.
The rd.live.overlay.readonly option, which allows a persistent overlayfs
to be mounted read-only through a higher level transient overlay directory,
has been implemented through the multiple lower layers feature of
OverlayFS.
ZIPL
rd.zipl=<path to blockdevice>Update the dracut commandline with the values
found in the dracut-cmdline.conf file on the given device. The values
are merged into the existing commandline values and the udev events are
regenerated.
Example.
rd.zipl=UUID=0fb28157-99e3-4395-adef-da3f7d44835a
CIO_IGNORE
rd.cio_accept=<device-ids>Remove the devices listed in
<device-ids> from the default cio_ignore kernel command-line settings.
<device-ids> is a list of comma-separated CCW device ids. The default
for this value is taken from the /boot/zipl/active_devices.txt file.
Example.
rd.cio_accept=0.0.0180,0.0.0800,0.0.0801,0.0.0802
Plymouth Boot Splash
plymouth.enable=0disable the plymouth bootsplash
completely.
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.
Example.
masterkeytype=<kernel master key type>
masterkey=/etc/keys/kmk-trusted.blob
Set the type of the kernel master key.
Example.
evmkey=<EVM HMAC key path name>
masterkeytype=trusted
Set the path name of the EVM HMAC key.
Example.
evmx509=<EVM X.509 cert path name>
evmkey=/etc/keys/evm-trusted.blob
Set the path name of the EVM X.509
certificate.
Example.
ecryptfskey=<eCryptfs key path name>
evmx509=/etc/keys/x509_evm.der
Set the path name of the eCryptfs key.
Example.
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. rdbreakrd.break
rd.ccw
rd.znet
rd_CCW
rd.znet
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
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.
Deprecated, better use /etc/cmdline.d/*.conf.
/etc/cmdline.d/*.conf
Can contain additional command line
options.
AUTHOR
Harald HoyerSEE ALSO
dracut(8) dracut.conf(5)NOTES
- 1.
- rfc4173
2022-10-21 | dracut 059-4 |