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5 <title>dracut.kernel</title>
6 <productname>dracut</productname>
9 <contrib>Developer</contrib>
10 <firstname>Harald</firstname>
11 <surname>Hoyer</surname>
12 <email>harald@redhat.com</email>
17 <refentrytitle>dracut.kernel</refentrytitle>
18 <manvolnum>7</manvolnum>
19 <refmiscinfo class="version"/>
22 <refname>dracut.kernel</refname>
23 <refpurpose>dracut kernel command line options</refpurpose>
26 <title>Description</title>
27 <para>The root filesystem used by the kernel is specified in the boot configuration
28 file, as always. The traditional <emphasis remap="B">root=/dev/hda1</emphasis> style device
29 specification is allowed. If a label is used, as in <emphasis remap="B">root=LABEL=rootPart</emphasis>
30 the initramfs will search all available devices for an ext2 or ext3 filesystem
31 with the appropriate label, and mount that device as the root filesystem.
32 <emphasis remap="B">root=UUID=uuidnumber</emphasis> will mount the partition with that UUID as the
33 root filesystem.</para>
35 <title>Standard</title>
39 <envar>init=<replaceable><path to real init></replaceable></envar>
47 <envar>root=<replaceable><path to blockdevice></replaceable></envar>
50 <para>specify blockdevice to use as root filesystem.
54 root=/dev/disk/by-path/pci-0000:00:1f.1-scsi-0:0:1:0-part1
55 </programlisting></para>
60 <envar>rootfstype=<replaceable><filesystem type></replaceable></envar>
63 <para>"auto" if not specified, e.g. rootfstype=ext3</para>
68 <envar>rootflags=<replaceable><mount options></replaceable></envar>
71 <para>specify additional mount options for the root filesystem. If not set, /etc/fstab
72 of the real root will be parsed for special mount options and mounted
78 <envar>rd_NO_FSTAB</envar>
81 <para>do not honor special mount options for the root filesystem found in
82 /etc/fstab of the real root.</para>
92 <envar>rdblacklist=<replaceable><drivername></replaceable></envar>
95 <para>do not load kernel module <drivername>
96 This parameter can be specified multiple times.</para>
101 <envar>rdloaddriver=<replaceable><drivername></replaceable></envar>
104 <para>force loading kernel module <drivername>
105 This parameter can be specified multiple times.</para>
115 <envar>rdinfo</envar>
118 <para>print informational output though "quiet" is set</para>
123 <envar>rdshell</envar>
126 <para>allow dropping to a shell, if root mounting fails</para>
131 <envar>rdinitdebug</envar>
134 <para>set -x for the dracut shell and logs to dmesg, console and /init.log</para>
139 <envar>rdbreak</envar>
142 <para>drop to a shell at the end</para>
146 <term><envar>rdbreak=</envar>{cmdline|pre-udev|pre-trigger|initqueue|pre-mount|mount|pre-pivot} </term>
148 <para>drop to a shell on defined breakpoint</para>
153 <envar>rdudevinfo</envar>
156 <para>set udev to loglevel info</para>
161 <envar>rdudevdebug</envar>
164 <para>set udev to loglevel debug</para>
174 SYSFONT=latarcyrheb-sun16
175 KEYTABLE=de-latin1-nodeadkeys
181 <envar>KEYBOARDTYPE=</envar>
182 <replaceable>{sun|pc}</replaceable>
185 <para>will be written to /etc/sysconfig/keyboard in the initramfs</para>
190 <envar>KEYTABLE=<replaceable><keytable filename></replaceable></envar>
193 <para>will be written to /etc/sysconfig/keyboard in the initramfs</para>
198 <envar>SYSFONT=<replaceable><Console font></replaceable></envar>
201 <para>will be written to /etc/sysconfig/i18n in the initramfs</para>
206 <envar>SYSFONTACM=</envar>
207 <replaceable><Console map></replaceable>
210 <para>will be written to /etc/sysconfig/i18n in the initramfs</para>
215 <envar>UNIMAP=<replaceable><Unicode font map></replaceable></envar>
218 <para>will be written to /etc/sysconfig/i18n in the initramfs</para>
223 <envar>LANG=<replaceable><locale></replaceable></envar>
226 <para>will be written to /etc/sysconfig/i18n in the initramfs</para>
236 <envar>rd_NO_LVM</envar>
239 <para>disable LVM detection</para>
244 <envar>rd_LVM_VG=<replaceable><volume group name></replaceable></envar>
247 <para>only activate the volume groups with the given name
248 rd_LVM_VG can be specified multiple times on the kernel command line.</para>
253 <envar>rd_LVM_LV=<replaceable><logical volume name></replaceable></envar>
256 <para>only activate the logical volumes with the given name
257 rd_LVM_LV can be specified multiple times on the kernel command line.</para>
262 <envar>rd_NO_LVMCONF</envar>
265 <para>remove any /etc/lvm/lvm.conf, which may exist in the initramfs</para>
271 <title>crypto LUKS</title>
275 <envar>rd_NO_LUKS</envar>
278 <para>disable crypto LUKS detection</para>
283 <envar>rd_LUKS_UUID=<replaceable><luks uuid></replaceable></envar>
286 <para>only activate the LUKS partitions with the given UUID
287 Any "luks-" of the LUKS UUID is removed before comparing to <luks uuid>.
288 The comparisons also matches, if <luks uuid> is only the beginning of the
289 LUKS UUID, so you don't have to specify the full UUID.
290 This parameter can be specified multiple times.</para>
295 <envar>rd_NO_CRYPTTAB</envar>
298 <para>do not check, if LUKS partition is in /etc/crypttab</para>
308 <envar>rd_NO_MD</envar>
311 <para>disable MD RAID detection</para>
316 <envar>rd_NO_MDIMSM</envar>
319 <para>no MD RAID for imsm/isw raids, use dmraid instead</para>
324 <envar>rd_NO_MDADMCONF</envar>
327 <para>ignore mdadm.conf included in initramfs</para>
332 <envar>rd_MD_UUID=<replaceable><md uuid></replaceable></envar>
335 <para>only activate the raid sets with the given UUID.
336 This parameter can be specified multiple times.</para>
342 <title>DMRAID</title>
346 <envar>rd_NO_DM</envar>
349 <para>disable DM RAID detection</para>
354 <envar>rd_DM_UUID=<replaceable><dmraid uuid></replaceable></envar>
357 <para>only activate the raid sets with the given UUID.
358 This parameter can be specified multiple times.</para>
364 <title>Network</title>
369 <replaceable>{dhcp|on|any|dhcp6|auto6}</replaceable>
372 <para>dhcp|on|any: get ip from dhcp server from all interfaces. If root=dhcp,
373 loop sequentially through all interfaces (eth0, eth1, ...) and use the first
374 with a valid DHCP root-path.</para>
375 <para>auto6: do IPv6 autoconfiguration</para>
379 <term><envar>ip=</envar><replaceable><interface></replaceable>:<replaceable>{dhcp|on|any|dhcp6|auto6}</replaceable></term>
381 <para>dhcp|on|any|dhcp6: get ip from dhcp server on a specific interface
382 auto6: do IPv6 autoconfiguration
383 This parameter can be specified multiple times.</para>
387 <term><envar>ip=</envar><replaceable><client-IP></replaceable>:<optional>
388 <replaceable><server-id></replaceable>
389 </optional>:<replaceable><gateway-IP></replaceable>:<replaceable><netmask></replaceable>:<replaceable><client_hostname></replaceable>:<replaceable><interface></replaceable>:<replaceable>{none|off}</replaceable></term>
391 <para>explicit network configuration. If you want do define a IPv6 address, put it in brackets (e.g. [2001:DB8::1]).
392 This parameter can be specified multiple times.</para>
396 <term><envar>ifname=</envar><replaceable><interface></replaceable>:<replaceable><MAC></replaceable></term>
398 <para>Assign network device name <interface> (ie eth0) to the NIC with MAC <MAC>.
399 Note letters in the MAC-address must be lowercase!
400 Note that if you use this option you <emphasis remap="B">must</emphasis> specify an ifname= argument
401 for all interfaces used in ip= or fcoe= arguments
402 This parameter can be specified multiple times.</para>
407 <envar>bootdev=</envar>
408 <replaceable><interface></replaceable>
411 <para>specify network interface to use routing and netroot information from.
412 Required if multiple ip= lines are used.</para>
417 <envar>nameserver=</envar>
418 <replaceable><IP></replaceable>
419 <optional><envar>nameserver</envar>=<replaceable><IP></replaceable> ...</optional>
422 <para>specify nameserver(s) to use</para>
433 <optional><replaceable><server-ip></replaceable>:</optional>
434 <replaceable><root-dir></replaceable>
435 <optional>:<replaceable><nfs-options></replaceable></optional>
438 <para>mount nfs share from <server-ip>:/<root-dir>, if no server-ip is given,
439 use dhcp next_server. if server-ip is an IPv6 address it has to be put in brackets, e.g. [2001:DB8::1].
440 NFS options can be appended with the prefix ":" or "," and are seperated by ",".</para>
444 <term><envar>root=</envar>nfs:<optional><replaceable><server-ip></replaceable>:</optional><replaceable><root-dir></replaceable><optional>:<replaceable><nfs-options></replaceable></optional></term>
445 <term><envar>root=</envar>nfs4:<optional><replaceable><server-ip></replaceable>:</optional><replaceable><root-dir></replaceable><optional>:<replaceable><nfs-options></replaceable></optional></term>
448 <replaceable>{dhcp|dhcp6}</replaceable>
451 <para>root=dhcp alone directs initrd to look at the DHCP root-path where NFS
452 options can be specified.
453 root-path=<server-ip>:<root-dir>[,<nfs-options>]
454 root-path=nfs:<server-ip>:<root-dir>[,<nfs-options>]
455 root-path=nfs4:<server-ip>:<root-dir>[,<nfs-options>]</para>
461 <filename>/dev/nfs</filename>
462 <envar> nfsroot=</envar>
463 <optional><replaceable><server-ip></replaceable>:</optional>
464 <replaceable><root-dir></replaceable>
465 <optional>:<replaceable><nfs-options></replaceable></optional>
468 <para><emphasis remap="B">Deprecated!</emphasis> kernel Documentation/filesystems/nfsroot.txt defines
470 This is supported by dracut but not recommended.</para>
475 <envar remap="B">rd_NFS_DOMAIN=</envar>
476 <replaceable><NFSv4 domain name></replaceable>
479 <para>Set the NFSv4 domain name. Will overwrite the settings in /etc/idmap.conf.</para>
488 <term><envar>root=</envar>iscsi:<optional><replaceable><username></replaceable>:<replaceable><password></replaceable><optional>:<replaceable><reverse></replaceable>:<replaceable><password></replaceable></optional>@</optional><optional>
489 <replaceable><servername></replaceable>
490 </optional>:<optional>
491 <replaceable><protocol></replaceable>
492 </optional>:<optional>
493 <replaceable><port></replaceable>
494 </optional>:<optional>
495 <replaceable><LUN></replaceable>
496 </optional>:<replaceable><targetname></replaceable></term>
498 <para>protocol defaults to "6", LUN defaults to "0".</para>
499 <para>If the "servername" field is provided by BOOTP or DHCP, then that
500 field is used in conjunction with other associated fields to contact
501 the boot server in the Boot stage (Section 7). However, if the
502 "servername" field is not provided, then the "targetname" field is
503 then used in the Discovery Service stage in conjunction with other
504 associated fields.</para>
505 <para><ulink url="http://tools.ietf.org/html/rfc4173">http://tools.ietf.org/html/rfc4173</ulink></para>
508 root=iscsi:192.168.50.1::::iqn.2009-06.dracut:target0
511 <para>If servername is an IPv6 address, it has to be put in brackets. e.g.
513 root=iscsi:[2001:DB8::1]::::iqn.2009-06.dracut:target0
514 </programlisting></para>
518 <term><envar>root=</envar><replaceable>???</replaceable><envar> netroot=</envar>iscsi:<optional><replaceable><username></replaceable>:<replaceable><password></replaceable><optional>:<replaceable><reverse></replaceable>:<replaceable><password></replaceable></optional>@</optional><optional>
519 <replaceable><servername></replaceable>
520 </optional>:<optional>
521 <replaceable><protocol></replaceable>
522 </optional>:<optional>
523 <replaceable><port></replaceable>
524 </optional>:<optional>
525 <replaceable><LUN></replaceable>
526 </optional>:<replaceable><targetname></replaceable> ...</term>
528 <para>multiple netroot options allow setting up multiple iscsi disks. e.g.
531 netroot=iscsi:192.168.50.1::::iqn.2009-06.dracut:target0
532 netroot=iscsi:192.168.50.1::::iqn.2009-06.dracut:target1
533 </programlisting></para>
534 <para>If servername is an IPv6 address, it has to be put in brackets.
536 <programlisting>netroot=iscsi:[2001:DB8::1]::::iqn.2009-06.dracut:target0</programlisting></para>
541 <envar>root=<replaceable>???</replaceable></envar>
542 <envar> iscsi_initiator=<replaceable><initiator> </replaceable></envar>
543 <envar>iscsi_target_name=<replaceable><target_name> </replaceable></envar>
544 <envar>iscsi_target_ip=<replaceable><target ip> </replaceable></envar>
545 <envar>iscsi_target_port=<replaceable><target port> </replaceable></envar>
546 <envar>iscsi_target_group=<replaceable><target group> </replaceable></envar>
547 <envar>iscsi_username=<replaceable><username> </replaceable></envar>
548 <envar>iscsi_password=<replaceable><password> </replaceable></envar>
549 <envar>iscsi_in_username=<replaceable><in username> </replaceable></envar>
550 <envar>iscsi_in_password=<replaceable><in password> </replaceable></envar>
553 <para>manually specify all iscsistart parameter (see <userinput>iscsistart --help</userinput>)</para>
557 <term><envar>root=</envar>???<envar> iscsi_firmware</envar></term>
559 <para>will read the iscsi parameter from the BIOS firmware</para>
568 <term><envar>netroot=</envar>fcoe:<replaceable><interface|MAC></replaceable>:<replaceable>{dcb|nodcb}</replaceable></term>
570 <para>Try to connect to a FCoE SAN through the NIC specified by <interface> or <MAC>,
571 for the second argument, currently only nodcb is supported. Note letters in
572 the MAC-address must be lowercase!</para>
581 <term><envar>root=</envar><constant>nbd</constant>:<replaceable><server></replaceable>:<replaceable><port></replaceable><optional>:<replaceable><fstype></replaceable></optional><optional>:<replaceable><mountopts></replaceable></optional></term>
583 <para>mount nbd share from <server></para>
588 <envar>root=dhcp</envar>
591 <para>with dhcp root-path=nbd:<server>:<port>[:<fstype>][:<mountopts>]
592 root=dhcp alone directs initrd to look at the DHCP root-path where NBD
593 options can be specified.
594 This syntax is only usable in cases where you are directly mounting the volume
595 as the rootfs.</para>
604 <term><envar>rd_DASD_MOD=</envar>....</term>
606 <para>same syntax as the kernel module parameter (s390 only)</para>
611 <envar>rd_DASD=</envar>
612 <replaceable><dasd_adaptor device bus ID></replaceable>
613 <optional>,readonly=<replaceable>X</replaceable></optional>
614 <optional>,use_diag=<replaceable>X</replaceable></optional>
615 <optional>,erplog=<replaceable>X</replaceable></optional>
618 <para>activate DASD device with the given adaptor device bus ID and setting the sysfs attributes
619 to the specified values
620 This parameter can be specified multiple times.</para>
629 <term><envar>rd_ZFCP=</envar><replaceable><zfcp adaptor device bus ID></replaceable>,<replaceable><WWPN></replaceable>,<replaceable><FCPLUN></replaceable></term>
631 <para>rd_ZFCP can be specified multiple times on the kernel command line.</para>
632 <para>example: rd_ZFCP=0.0.4000,0x5005076300C213e9,0x5022000000000000</para>
637 <envar>rd_NO_ZFCPCONF</envar>
640 <para>ignore zfcp.conf included in the initramfs</para>
649 <term><envar>rd_ZNET=</envar><replaceable><nettype></replaceable>,<replaceable><subchannels></replaceable>,<replaceable><options></replaceable></term>
651 <para>rd_ZNET can be specified multiple times on the kernel command line. Examples:
652 rd_ZNET=qeth,0.0.0600,0.0.0601,0.0.0602,layer2=1,portname=foo
653 rd_ZNET=ctc,0.0.0600,0.0.0601,0.0.0602,protocol=bar</para>
659 <title>Plymouth Boot Splash</title>
663 <envar>rd_NO_PLYMOUTH</envar>
666 <para>do not start plymouth. This will not work with encrypted partitions.</para>
677 <filename>/var/log/dracut.log</filename>
680 <para>logfile of initramfs image creation</para>
685 <filename>/tmp/dracut.log</filename>
688 <para>logfile of initramfs image creation, if /var/log/dracut.log is not writable</para>
693 <filename>/etc/dracut.conf</filename>
696 <para>see <citerefentry>
697 <refentrytitle>dracut.conf</refentrytitle>
698 <manvolnum>5</manvolnum>
699 </citerefentry></para>
704 <filename>/etc/dracut.conf.d/*.conf</filename>
707 <para>see <citerefentry>
708 <refentrytitle>dracut.conf</refentrytitle>
709 <manvolnum>5</manvolnum>
710 </citerefentry></para>
715 <title>Configuration in the Initramfs</title>
719 <filename>/conf/conf.d/</filename>
722 <para>Any files found in /conf/conf.d/ will be sourced in the initramfs to
723 set initial values. Command line options will override these values
724 set in the configuration files.</para>
729 <filename>/etc/cmdline</filename>
732 <para>Can contain additional command line options.</para>
739 <title>See Also</title>
742 <refentrytitle>dracut</refentrytitle>
743 <manvolnum>8</manvolnum>
746 <refentrytitle>dracut.conf</refentrytitle>
747 <manvolnum>5</manvolnum>