dracut.kernel(category10-web-server.html) - phpMan

DRACUT.CMDLINE(7)                   dracut                   DRACUT.CMDLINE(7)

NAME
       dracut.cmdline - dracut kernel command line options
DESCRIPTION
       The root device used by the kernel is specified in the boot
       configuration file on the kernel command line, as always.
       The traditional root=/dev/sda1 style device specification is allowed,
       but not encouraged. The root device should better be identified by
       LABEL or UUID. If a label is used, as in root=LABEL=<label_of_root> the
       initramfs will search all available devices for a filesystem with the
       appropriate label, and mount that device as the root filesystem.
       root=UUID=<uuidnumber> will mount the partition with that UUID as the
       root filesystem.
       In the following all kernel command line parameters, which are
       processed by dracut, are described.
       "rd.*" parameters mentioned without "=" are boolean parameters. They
       can be turned on/off by setting them to {0|1}. If the assignment with
       "=" is missing "=1" is implied. For example rd.info can be turned off
       with rd.info=0 or turned on with rd.info=1 or rd.info. The last value
       in the kernel command line is the value, which is honored.
   Standard
       init=<path to real init>
           specify the path to the init programm to be started after the
           initramfs has finished
       root=<path to blockdevice>
           specify the block device to use as the root filesystem.
           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.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.
   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 wait for devices to appear. 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.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 safed 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.
   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:
           o   firmware/bios-provided index numbers for on-board devices
           o   firmware-provided pci-express hotplug slot index number
           o   physical/geographical location of the hardware
           o   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"
               o   eno1
           PCI ethernet card in hotplug slot with firmware index number
               o   ens1
           PCI ethernet multi-function card with 2 ports
               o   enp2s0f0
               o   enp2s0f1
           PCI wlan card
               o   wlp3s0
           USB built-in 3G modem
               o   wwp0s29u1u4i6
           USB Android phone
               o   enp0s29u1u2
       ip={dhcp|on|any|dhcp6|auto6|either6}
           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
           either6
               if auto6 fails, then dhcp6
       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
       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>]]
           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. 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 overwrite 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}
           Try to connect to a FCoE SAN through the NIC specified by
           <interface> or <MAC> or EDD settings. For the second argument,
           currently only nodcb is supported. This parameter can be specified
           multiple times.
               Note
               letters in the MAC-address must be lowercase!
   NBD
       root=???
       netroot=nbd:<server>:<port>[:<fstype>[:<mountopts>[:<nbdopts>]]]
           mount nbd share from <server>
       root=dhcp with dhcp
       root-path=nbd:<server>:<port>[:<fstype>[:<mountopts>[:<nbdopts>]]]
           root=dhcp alone directs initrd to look at the DHCP root-path where
           NBD options can be specified. This syntax is only usable in cases
           where you are directly mounting the volume as the rootfs.
   DASD
       rd.dasd=....
           same syntax as the kernel module parameter (s390 only)
   ZFCP
       rd.zfcp=<zfcp adaptor device bus ID>,<WWPN>,<FCPLUN>
           rd.zfcp can be specified multiple times on the kernel command line.
           Example.
               rd.zfcp=0.0.4000,0x5005076300C213e9,0x5022000000000000

       rd.zfcp.conf=0
           ignore zfcp.conf included in the initramfs
   ZNET
       rd.znet=<nettype>,<subchannels>,<options>
           rd.znet can be specified multiple times on the kernel command line.
       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 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 are
           exhaused, the live filesystem becomes unusable and requires a
           reboot.
           The filesystem structure is expected to be:
               squashfs.img          |  Squashfs downloaded via network
                  !(mount)
                  /LiveOS
                      |- ext3fs.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.
       writable filesystem image
           The system will retrieve a compressed filesystem image, connect it
           to a loopback device, and mount it as a writable volume. 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.
           The filesystem structure is expected to be:
               rootfs.tgz            |  Compressed tarball containing fileystem image
                  !(unpack)
                  /rootfs.img        |  Filesystem image
                     !(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.
       root=live:<url>
           Boots a live image retrieved from <url>. Valid handlers: http,
           httpd, ftp, tftp.
           Example.
               root=live:http://example.com/liveboot.img
               root=live:ftp://ftp.example.com/liveboot.img

       rd.live.debug=1
           Enables debug output from the live boot process.
       rd.live.dir=<path>
           Specifies the directory within the squashfs where the ext3fs.img or
           rootfs.img can be found. By default, this is LiveOS.
       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) 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 root=live:<url>__ option.
       +
       Example.
           rd.live.overlay=/dev/sdb1:persistent-overlay.img

       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 which 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.writable.fsimg=1
           Enables writable filesystem support. The system will boot with a
           fully writable 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.
   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.ccw
       rd_DASD_MOD
           rd.dasd
       rd_DASD
           rd.dasd
       rdinitdebug rdnetdebug
           rd.debug
       rd_NO_DM
           rd.dm=0
       rd_DM_UUID
           rd.dm.uuid
       rdblacklist
           rd.driver.blacklist
       rdinsmodpost
           rd.driver.post
       rdloaddriver
           rd.driver.pre
       rd_NO_FSTAB
           rd.fstab=0
       rdinfo
           rd.info
       check
           rd.live.check
       rdlivedebug
           rd.live.debug
       live_dir
           rd.live.dir
       liveimg
           rd.live.image
       overlay
           rd.live.overlay
       readonly_overlay
           rd.live.overlay.readonly
       reset_overlay
           rd.live.overlay.reset
       live_ram
           rd.live.ram
       rd_NO_CRYPTTAB
           rd.luks.crypttab=0
       rd_LUKS_KEYDEV_UUID
           rd.luks.keydev.uuid
       rd_LUKS_KEYPATH
           rd.luks.keypath
       rd_NO_LUKS
           rd.luks=0
       rd_LUKS_UUID
           rd.luks.uuid
       rd_NO_LVMCONF
           rd.lvm.conf
       rd_LVM_LV
           rd.lvm.lv
       rd_NO_LVM
           rd.lvm=0
       rd_LVM_SNAPSHOT
           rd.lvm.snapshot
       rd_LVM_SNAPSIZE
           rd.lvm.snapsize
       rd_LVM_VG
           rd.lvm.vg
       rd_NO_MDADMCONF
           rd.md.conf=0
       rd_NO_MDIMSM
           rd.md.imsm=0
       rd_NO_MD
           rd.md=0
       rd_MD_UUID
           rd.md.uuid
       rd_NFS_DOMAIN
           rd.nfs.domain
       iscsi_initiator
           rd.iscsi.initiator
       iscsi_target_name
           rd.iscsi.target.name
       iscsi_target_ip
           rd.iscsi.target.ip
       iscsi_target_port
           rd.iscsi.target.port
       iscsi_target_group
           rd.iscsi.target.group
       iscsi_username
           rd.iscsi.username
       iscsi_password
           rd.iscsi.password
       iscsi_in_username
           rd.iscsi.in.username
       iscsi_in_password
           rd.iscsi.in.password
       iscsi_firmware
           rd.iscsi.firmware=0
       rd_NO_PLYMOUTH
           rd.plymouth=0
       rd_retry
           rd.retry
       rdshell
           rd.shell
       rd_NO_SPLASH
           rd.splash
       rdudevdebug
           rd.udev.debug
       rdudevinfo
           rd.udev.info
       rd_NO_ZFCPCONF
           rd.zfcp.conf=0
       rd_ZFCP
           rd.zfcp
       rd_ZNET
           rd.znet
       KEYMAP
           vconsole.keymap
       KEYTABLE
           vconsole.keymap
       SYSFONT
           vconsole.font
       CONTRANS
           vconsole.font.map
       UNIMAP
           vconsole.font.unimap
       UNICODE
           vconsole.unicode
       EXT_KEYMAP
           vconsole.keymap.ext
   Configuration in the Initramfs
       /etc/conf.d/
           Any files found in /etc/conf.d/ will be sourced in the initramfs to
           set initial values. Command line options will override these values
           set in the configuration files.
       /etc/cmdline
           Can contain additional command line options. 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

dracut                            09/30/2020                 DRACUT.CMDLINE(7)