DragonFly On-Line Manual Pages

Search: Section:  

MKINITRD(8)	       DragonFly System Manager's Manual	   MKINITRD(8)


NAME

     mkinitrd -- build an initial ramdisk image for use as early userland


SYNOPSIS

     mkinitrd [-b bootdir] [-c contentsdir] [-t tmpdir] [-s size]
	      [-S max_size]


DESCRIPTION

     The mkinitrd script builds a ramdisk (md) image based on the UFS filesys-
     tem containing only the most basic tools, such as a minimal init(8),
     sh(1), various mount(8) utilities, lvm(8), cryptsetup(8), tcplay(8), as
     well as some basic networking tools.  And the ramdisk is required to help
     mount the encrypted root partition.

     The contents of /usr/share/initrd will be copied onto the ramdisk, main-
     taining the same hierarchy.  This directory can be changed with the -c
     option.

     By default mkinitrd will calculate the contents size and create a ramdisk
     just big enough.  The -s option accepting an integer (number of MB) can
     specify the required size of the ramdisk.	The special value of 0 can be
     given to ignore the INITRD_SIZE setting from the configuration file as
     described below.  The -S option also accepts an integer (number of MB)
     and constrains the maximum allowed size of the ramdisk.  Specifying a
     value of 0 will ignore the INITRD_SIZE_MAX setting from the configuration
     file.

     On completion, the final image will be copied to
     /boot/kernel/initrd.img.gz, ready to be used as an early userland.  The
     base directory for kernel/initrd.img.gz can be changed with the -b option
     to an optional bootdir (the default is /boot).  The temporary directory
     to be used for setting up the image can be specified using the -t option
     (the default is /tmp).

     The mkinitrd script will read /etc/mkinitrd.conf if it exists and use the
     configuration from this file to override the following variables
     (defaults are in /etc/defaults/mkinitrd.conf):

	   BUILD_DIR
	   INITRD_SIZE_MAX
	   INITRD_DIRS
	   CONTENT_DIRS

     Adding the following lines to /boot/loader.conf will enable the use of
     the created initrd image:

	   initrd.img_load="YES"
	   initrd.img_type="md_image"
	   vfs.root.mountfrom="ufs:md0s0"

     The format for vfs.root.realroot in /boot/loader.conf that allows the
     user to specify what system to mount as the new root in the initrd is
     specified in its general form below:

	   vfs.root.realroot="<type>:[arg1[:arg2[:argN]]]"

     Currently, three types of real root are supported, local, tcplay and
     crypt.  The local type allows to mount any local file system that does
     not require any special setup apart from the initial discovery and call-
     ing the mount program. The general format is as follows:

	   vfs.root.realroot="local:<FS TYPE>:<DEVICE PATH>[:<OPTIONS>]"

     The crypt type allows to mount volumes supported by cryptsetup. The
     device will be set up by prompting the user for his key, and this volume
     will then be mounted as the new root.

	   vfs.root.realroot="crypt:<FS TYPE>:<DEVICE PATH>:<VOLUME NAME>[:<OPTIONS>]"

     The tcplay type allows to mount volumes supported by tcplay(8).  The
     device will be set up by prompting the user for his key, and this volume
     will then be mounted as the new root.

	   vfs.root.realroot="tcplay:<FS TYPE>:<DEVICE PATH>:<VOLUME NAME>[:<OPTIONS>]"


EXAMPLES

	   vfs.root.realroot="local:ufs:/dev/vg00/lv0[:OPTIONS]"

	   vfs.root.realroot="crypt:ufs:/dev/ad0s0a:secvolume[:OPTIONS]"

	   vfs.root.realroot="crypt:hammer2:/dev/serno/XXXXXX.s1d:root[:OPTIONS]"


SEE ALSO

     md(4), loader.conf(5)


HISTORY

     The mkinitrd command first appeared in DragonFly 2.7.


AUTHORS

     mkinitrd was written by Alex Hornung <ahornung@gmail.com>.

DragonFly 5.3			March 30, 2018			 DragonFly 5.3

Search: Section: