Provided by: dracut-core_047-2_amd64 bug

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 program to be started after the initramfs has finished

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

           Example.

               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

       rootfstype=<filesystem type>
           "auto" if not specified.

           Example.

               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.

       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.

               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

       rd.skipfsck
           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
       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 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 30 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.

   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.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. 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=[0-4]
           Print memory usage info at various points, set the verbose level from 0 to 4.

               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 + tracekomem
                       NOTE: tracekomem is a shell script utilizing kernel trace to track
                             the rough total memory consumption of kernel modules during
                             loading. It may override other trace configurations.

       rd.break
           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 on defined breakpoint

       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=de-latin1-nodeadkeys

       rd.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

       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=LatArCyrHeb-16

       rd.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

       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.LANG=pl_PL.utf8

       rd.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:

           Example.

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

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

               Note
               dracut pipes key to cryptsetup with -d - argument, therefore you need to pipe to
               crypsetup luksFormat with -d -, too!

               Here follows example for key encrypted with GPG:

                   gpg --quiet --decrypt rootkey.gpg | \
                   cryptsetup -d - -v --cipher serpent-cbc-essiv:sha256 \
                   --key-size 256 luksFormat /dev/sda3

               If you use plain keys, just add path to -d option:

                   cryptsetup -d rootkey.key -v --cipher serpent-cbc-essiv:sha256 \
                    --key-size 256 luksFormat /dev/sda3

   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.

   MULTIPATH
       rd.multipath=0
           disable multipath detection

   FIPS
       rd.fips
           enable FIPS

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

           Example.

               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
           Important
           It is recommended to either bind an interface to a MAC with the ifname argument, or to
           use the systemd-udevd predictable network interface names.

           Predictable network interface device names based on:

           ·   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

           See: http://www.freedesktop.org/wiki/Software/systemd/PredictableNetworkInterfaceNames

           Two character prefixes based on the type of interface:

           en
               ethernet

           wl
               wlan

           ww
               wwan

           Type of names:

           o<index>
               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

           All multi-function PCI devices will carry the [f<function>] number in the device name,
           including the function 0 device.

           When using PCI geography, The PCI domain is only prepended when it is not 0.

           For USB devices the full chain of port numbers of hubs is composed. If the name gets
           longer than the maximum number of 15 characters, the name is not exported. The usual
           USB configuration == 1 and interface == 0 values are suppressed.

           PCI ethernet card with firmware index "1"

               ·   eno1

           PCI ethernet card in hotplug slot with firmware index number

               ·   ens1

           PCI ethernet multi-function card with 2 ports

               ·   enp2s0f0

               ·   enp2s0f1

           PCI wlan card

               ·   wlp3s0

           USB built-in 3G modem

               ·   wwp0s29u1u4i6

           USB Android phone

               ·   enp0s29u1u2

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

           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

       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>. This cannot be used in conjunction
               with the ifname argument for the same <interface>.

       ip=<client-IP>:[<peer>]:<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.  <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>
               optionally set <macaddr> on the <interface>. This cannot be used in conjunction
               with the ifname argument for the same <interface>.

       ip=<client-IP>:[<peer>]:<gateway-IP>:<netmask>:<client_hostname>:<interface>:{none|off|dhcp|on|any|dhcp6|auto6|ibft}[:[<dns1>][:<dns2>]]
           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> (ie "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.

                   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

       bootdev=<interface>
           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 <phydeivce>. 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>
           Setup team device <teammaster> on top of <teamslaves>. <teamslaves> is a
           comma-separated list of physical (ethernet) interfaces.

       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
           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.

           Example.

                   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 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 5 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.

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

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

           Example.

               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:

           Example.

               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:

           Example.

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

               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>
           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.param=<param>
           <param> will be passed as "--param <param>" to iscsistart. This parameter can be
           specified multiple times.

           Example.

               "netroot=iscsi rd.iscsi.firmware=1 rd.iscsi.param=node.session.timeo.replacement_timeout=30"

           will result in

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

       rd.iscsi.ibft rd.iscsi.ibft=1: Turn on iBFT autoconfiguration for the interfaces

       rd.iscsi.waitnet=0: Turn off waiting for all interfaces to be up before trying to login to
       the iSCSI targets.

       rd.iscsi.testroute=0: Turn off checking, if the route to the iSCSI target IP is possible
       before trying to login.

   FCoE
       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!

   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=dhcp with dhcp
       root-path=nbd:<server>:<port/exportname>[:<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.

           NOTE: If "exportname" instead of "port" is given the standard port is used. Newer
           versions of nbd are only supported with "exportname".

   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=0.0.4000,0x5005076300C213e9,0x5022000000000000
               rd.zfcp=0.0.4000

       rd.zfcp.conf=0
           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.

           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 image
           The system will boot with a read only filesystem from the SquashFS and apply a
           writable device-mapper snapshot over the read only filesystem. Using this method
           ensures a relatively fast boot and lower RAM usage. Users must be careful to avoid
           writing too many blocks to the snapshot volume. Once the blocks of the snapshot
           overlay are exhausted, the root filesystem becomes read only and may cause application
           failures. The 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 expected to be:

               squashfs.img          |  Squashfs from LiveCD .iso downloaded via network
                  !(mount)
                  /LiveOS
                      |- rootfs.img  |  Filesystem image to mount read-only
                           !(mount)
                           /bin      |  Live filesystem
                           /boot     |
                           /dev      |
                           ...       |

           Dracut uses this method 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.

           ·   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 cause a
               temporary, writable overlay to be stacked over a read-only snapshot of the root
               filesystem.

       Uncompressed live filesystem image
           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.

           ·   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.

       writable filesystem image
           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:

               rootfs.tgz            |  Compressed tarball containing fileystem image
                  !(unpack)
                  /rootfs.img        |  Filesystem image at /run/initramfs/fsimg/
                     !(mount)
                     /bin            |  Live filesystem
                     /boot           |
                     /dev            |
                     ...             |

           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
           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>. Valid handlers: http, https, ftp, torrent,
           tftp.

           Example.

               root=live:http://example.com/liveboot.img
               root=live:ftp://ftp.example.com/liveboot.img
               root=live:torrent://example.com/liveboot.img.torrent

       rd.live.debug=1
           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, i.e., a DVD which needs to be ejected later on.

       rd.live.overlay=<devspec>:(<pathspec>|auto)|none
           Allow the usage of a permanent overlay.

           ·   <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.

           ·   none specifies no overlay when an uncompressed 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.

               Example.

                   rd.live.overlay=/dev/sdb1:persistent-overlay.img

       rd.live.overlay.size=<size_MiB>
           Specifies a non-persistent overlay size in MiB. The default is 32768.

       rd.live.overlay.readonly=1
           Specifies a non-persistent, writable snapshot overlay to be stacked over a read-only
           snapshot of the root filesystem, /dev/mapper/live-ro, or a read- only loop device of a
           writable rootfs.img.

       rd.live.overlay.reset=1
           Specifies that a persistent overlay should be reset on boot. All 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 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=0
           disable 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.

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

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

           Example.

               masterkeytype=trusted

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

           Example.

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

       ecryptfskey=<eCryptfs key path name>
           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.

       rdbreak
           rd.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_NO_MULTIPATH: rd.multipath=0

       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. Deprecated, better use
           /etc/cmdline.d/*.conf.

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

AUTHOR

       Harald Hoyer

SEE ALSO

       dracut(8) dracut.conf(5)

NOTES

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