1 .TH DRACUT 8 "June 2009" "Linux"
3 switch_root \- switch to another filesystem as the root of the mount tree.
5 \fBdracut\fR [\fIOPTION\fR]... \fI<image>\fR \fI<kernel-version>\fR
9 \fBdracut\fR creates an initial image used by the kernel for
10 preloading the block device modules (such as IDE, SCSI or RAID)
11 which are needed to access the root filesystem.
15 .BR \-f ", " \-\-force
16 overwrite existing initramfs file.
18 .BR \-m ", " \-\-modules " \fILIST\fR"
19 specify a space-separated list of dracut modules to call
20 when building the initramfs.
21 Modules are located in
22 .IR /usr/share/dracut/modules.d .
24 .BR \-o ", " \-\-omit " \fILIST\fR"
25 omit a space-separated list of dracut modules.
27 .BR \-a ", " \-\-add " \fILIST\fR"
28 add a space-separated list of dracut modules.
30 .BR \-d ", " \-\-drivers " \fILIST\fR"
31 specify a space-separated list of kernel modules to include in the initramfs.
34 display help text and exit.
37 output debug information of the build process
39 .BR \-v ", " \-\-verbose
40 verbose output during the build process
42 .BR \-c ", " \-\-conf " \fIFILE\fR"
43 specify configuration file to use.
47 .BR \-l ", " \-\-local
48 local mode. Use modules from the current working
49 directory instead of the system-wide installed in
50 .IR /usr/share/dracut/modules.d .
51 Useful when running dracut from a git checkout.
53 .BR \-H ", " \-\-hostonly
54 Host-Only mode: Install only what is needed for
55 booting the local host instead of a generic host.
57 .BR \-i ", " \-\-include " \fISOURCE\fR" "" " \fITARGET\fR"
58 include the files in the SOURCE directory into the
59 target directory in the final initramfs.
61 .BR \-I ", " \-\-install " \fILIST\fR"
62 install the space separated list of files into the initramfs.
64 .SH KERNEL COMMAND LINE
65 The root filesystem used by the kernel is specified in the boot configuration
66 file, as always. The traditional \fBroot=/dev/hda1\fR style device
67 specification is allowed. If a label is used, as in \fBroot=LABEL=rootPart\fR
68 the initrd will search all available devices for an ext2 or ext3 filesystem
69 with the appropriate label, and mount that device as the root filesystem.
70 \fBroot=UUID=uuidnumber\fR will mount the partition with that UUID as the
75 .B init=<path to real init>
77 .B root=<path to blockdevice>
78 specify e.g. \fI/dev/sda1\fR or
79 \fI/dev/disk/by-path/pci-0000:00:1f.1-scsi-0:0:1:0-part1\fR
84 get IP from dhcp server, root-path option from dhcp specifies root location
88 .B root=[<server-ip>:]<root-dir>[:<nfs-options>]
89 mount nfs share from <server-ip>:/<root-dir>, if no server-ip is given,
91 NFS options can be appended with the prefix "." or ","
93 .B root=nfs:[<server-ip>:]<root-dir>[:<nfs-options>]
95 .B root=nfs4:[<server-ip>:]<root-dir>[:<nfs-options>]
98 root=dhcp alone directs initrd to look at the DHCP root-path where NFS
99 options can be specified.
100 root-path=<server-ip>:<root-dir>[,<nfs-options>]
101 root-path=nfs:<server-ip>:<root-dir>[,<nfs-options>]
102 root-path=nfs4:<server-ip>:<root-dir>[,<nfs-options>]
104 .B root=/dev/nfs nfsroot=[<server-ip>:]<root-dir>[,<nfs-options>]
105 \fBDeprecated!\fR kernel Documentation/filesystems/nfsroot.txt defines
107 This is supported by dracut but not recommended.
111 .B root=iscsi:[<servername>]:[<protocol>]:[<port>]:[<LUN>]:<targetname>
112 protocol defaults to "6", LUN defaults to "0".
114 If the "servername" field is provided by BOOTP or DHCP, then that
115 field is used in conjunction with other associated fields to contact
116 the boot server in the Boot stage (Section 7). However, if the
117 "servername" field is not provided, then the "targetname" field is
118 then used in the Discovery Service stage in conjunction with other
121 http://tools.ietf.org/html/rfc4173
124 .B root=iscsi:[<servername>]:[<protocol>]:[<port>]:[<LUN>]:<targetname>
125 e.g. root=iscsi:192.168.50.1::::iqn.2009-06.dracut:target0
128 .B root=??? netroot=iscsi:[<servername>]:[<protocol>]:[<port>]:[<LUN>]:<targetname> ...
129 multiple netroot options allow setting up multiple iscsi disks
131 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
132 .B not yet implemented
134 .B root=??? iscsi_initiator= iscsi_target_name= iscsi_target_ip= iscsi_target_port= iscsi_target_group= iscsi_username= iscsi_password= iscsi_in_username= iscsi_in_password=
137 .B root=??? iscsi_firmware
138 will read the iscsi parameter from the BIOS firmware
142 .B root=nbd:<server>:<port>[:<fstype>][:<mountopts>]
143 mount nbd share from <server>
146 with dhcp root-path=nbd:<server>:<port>[:<fstype>][:<mountopts>]
147 root=dhcp alone directs initrd to look at the DHCP root-path where NBD options can be specified.
148 This syntax is only usable in cases where you are directly mounting the volume as the rootfs.
151 .TP bootdev=<interface>
152 .B specify the network interface to boot from
155 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.
157 .B ip=<interface>:[dhcp|on|any]
158 get ip from dhcp server on a specific interface
160 .B ip=<client-IP-number>:<gateway-IP-number>:<netmask>:<client-hostname>:<interface>:[dhcp|on|any|]
161 explicit network configuration
165 .B rdblacklist=<drivername>
166 do not load kernel module <drivername>
171 set -x for the dracut shell
173 .B rdbreak=[pre-udev|pre-mount|mount|pre-pivot|]
174 drop the shell on defined breakpoint
177 set udev to loglevel info
180 set udev to loglevel debug
183 debug network scripts in dracut. Output is written to /tmp/
185 .SH CONFIGURATION IN INITRAMFS
188 Any files found in /conf/conf.d/ will be sourced in the initramfs to
189 set initial values. Command line options will override these values
190 set in the configuration files.
194 Andreas Thienemann <andreas@bawue.net>
195 Bill Nottingham <notting@redhat.com>
196 Dave Jones <davej@redhat.com>
197 David Dillow <dave@thedillows.org>
198 Harald Hoyer <harald@redhat.com>
199 Jeremy Katz <katzj@redhat.com>
200 Peter Jones <pjones@redhat.com>
201 Seewer Philippe <philippe.seewer@bfh.ch>
202 Victor Lowther <victor.lowther@gmail.com>
203 Warren Togami <wtogami@redhat.com>
206 The dracut command is part of the dracut package and is available from
207 https://sourceforge.net/apps/trac/dracut/wiki