Standard
~~~~~~~~
**init=**__<path to real init>__::
- specify the path to the init programm to be started after the initramfs has
+ specify the path to the init program to be started after the initramfs has
finished
**root=**__<path to blockdevice>__::
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.
+ 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.
+ 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
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.
+
+[listing]
+.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.
have been loaded. This parameter can be specified multiple times.
**rd.retry=**__<seconds>__::
- specify how long dracut should wait for devices to appear.
+ 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.
[[dracutkerneldebug]]
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.
+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.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 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=[0-3]**::
- Print memory usage info at various points, set the verbose level from 0 to 3. +
+**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:
+
----
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**::
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.
+ 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**::
**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
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
**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.
+ _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.
+_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:
+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:
+
[listing]
.Example
ignore mdadm.conf included in initramfs
**rd.md.waitclean=1**::
- wait for any resync, recovery, or reshape activity to finish before continuing
+ 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
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**::
[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.
+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:
- physical/geographical location of the hardware
- the interface's MAC address
-See: http://www.freedesktop.org/wiki/Software/systemd/PredictableNetworkInterfaceNames
+See:
+http://www.freedesktop.org/wiki/Software/systemd/PredictableNetworkInterfaceNames
Two character prefixes based on the type of interface:
* enp0s29u1u2
=====================
-**ip=**__{dhcp|on|any|dhcp6|auto6|ibft}__::
- dhcp|on|any::: get ip from dhcp server from all interfaces. If root=dhcp, loop
- sequentially through all interfaces (eth0, eth1, ...) and use the first with
- a valid DHCP root-path.
+**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
- ibft::: iBFT autoconfiguration
+ either6::: if auto6 fails, then dhcp6
**ip=**__<interface>__:__{dhcp|on|any|dhcp6|auto6}__[:[__<mtu>__][:__<macaddr>__]]::
This parameter can be specified multiple times.
same <interface>.
=====================
-**ip=**__<client-IP>__:[__<peer>__]:__<gateway-IP>__:__<netmask>__:__<client_hostname>__:__<interface>__:__{none|off|dhcp|on|any|dhcp6|auto6|ibft}__:[:[__<mtu>__][:__<macaddr>__]]::
+**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.
+ 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
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>.
+ 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.
++
+[listing]
+.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
**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)
+ 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>__]]::
+**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.
- Bond without parameters assumes bond=bond0:eth0,eth1:mode=balance-rr
+ <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>.
**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
+ 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
+ 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 ",".
+ ":" or "," and are separated 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
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_.
+ 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
~~~
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.
+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.
+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
~~~~~
fields. See
link:$$http://tools.ietf.org/html/rfc4173#section-5$$[rfc4173].
+
-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.
+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.
+
[listing]
.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.
+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.
+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.
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}__::
+**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. For the second argument, currently only nodcb is
- supported. This parameter can be specified multiple times.
+ _<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>__[:__<fstype>__[:__<mountopts>__[:__<nbdopts>__]]]::
- mount nbd share from <server>
+**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>__[:__<fstype>__[:__<mountopts>__[:__<nbdopts>__]]]::
+**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
~~~~
ZFCP
~~~~
**rd.zfcp=**__<zfcp adaptor device bus ID>__,__<WWPN>__,__<FCPLUN>__::
- rd.zfcp can be specified multiple times on the kernel command line.
+ 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.
+
[listing]
.Example
--
rd.zfcp=0.0.4000,0x5005076300C213e9,0x5022000000000000
+rd.zfcp=0.0.4000
--
**rd.zfcp.conf=0**::
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.
+
[listing]
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 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:
++
+[listing]
+--
+squashfs.img | SquashFS from LiveCD .iso
+ !(mount)
+ /LiveOS
+ |- rootfs.img | Filesystem image to mount read-only
+ !(mount)
+ /bin | Live filesystem
+ /boot |
+ /dev |
+ ... |
+--
++
+For OverlayFS mount overlays, the filesystem structure may also be a direct
+compression of the root filesystem:
++
+[listing]
+--
+squashfs.img | SquashFS from LiveCD .iso
+ !(mount)
+ /bin | Live filesystem
+ /boot |
+ /dev |
+ ... |
+--
++
+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.
++
+- 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.
++
+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:
++
+[listing]
+--
+rootfs.tgz | Compressed tarball containing filesystem 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>__. Requires the dracut 'livenet'
+module. Valid handlers: __http, https, ftp, torrent, tftp__.
++
+[listing]
+.Examples
+--
+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, 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.
++
+--
+* _<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
+`/<+++<b>rd.live.dir</b>+++>/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.
+--
++
+[listing]
+.Examples
+--
+rd.live.overlay=/dev/sdb1:persistent-overlay.img
+rd.live.overlay=UUID=99440c1f-8daa-41bf-b965-b7240a8996f4
+--
+
+**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.
++
+[listing]
+.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.
++
+[listing]
+.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 completly.
+ disable the plymouth bootsplash completely.
**rd.plymouth=0**::
disable the plymouth bootsplash only for the initramfs.
Deprecated, renamed Options
~~~~~~~~~~~~~~~~~~~~~~~~~~~
-Here is a list of options, which were used in dracut prior to version 008, and their new replacement.
+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.ccw:: rd.znet
+rd_CCW:: rd.znet
rd_DASD_MOD:: rd.dasd
rd_MD_UUID:: rd.md.uuid
+rd_NO_MULTIPATH: rd.multipath=0
+
rd_NFS_DOMAIN:: rd.nfs.domain
iscsi_initiator:: rd.iscsi.initiator
set in the configuration files.
_/etc/cmdline_::
- Can contain additional command line options. Deprecated, better use /etc/cmdline.d/*.conf.
+ Can contain additional command line options. Deprecated, better use
+ /etc/cmdline.d/*.conf.
_/etc/cmdline.d/*.conf_::
Can contain additional command line options.
projects / thirdparty / dracut.git / blobdiff