Ubuntu Manpage: live-boot - System Boot Scripts

NAME

       live-boot - System Boot Scripts

DESCRIPTION

       live-boot contains the scripts that configure a Debian Live system during the boot process
       (early userspace).

       live-boot is a hook for the initramfs-tools, used to generate a initramfs capable to  boot
       live systems, such as those created by live-helper(7). This includes the Debian Live isos,
       netboot tarballs, and usb stick images.

       At boot time it will look for a (read-only) media containing a "/live" directory  where  a
       root  filesystems (often a compressed filesystem image like squashfs) is stored. If found,
       it will create a writable environment, using aufs, for Debian like systems to boot from.

CONFIGURATION

       live-boot can be configured through a boot parameter or a configuration file.

       To configure  the  live-boot  parameters  used  by  default  in  a  live  image,  see  the
       --bootappend-live option in the lb_config(1) manual page.

   Kernel Parameters
       live-boot is only activated if 'boot=live' was used as a kernel parameter.

       In addition, there are some more boot parameters to influence the behaviour, see below.

   Configuration Files
       live-boot  can  be configured (but not activated) through configuration files. Those files
       can   be   placed   either   in   the   root   filesystem   itself   (/etc/live/boot.conf,
       /etc/live/boot/*), or on the live media (live/boot.conf, live/boot/*).

OPTIONS

live-boot currently features the following parameters.

access=ACCESS
Set the accessibility level for physically or visually impaired users. ACCESS must be
one of v1, v2, v3, m1, or m2. v1=lesser visual impairment, v2=moderate visual
impairment, v3=blindness, m1=minor motor difficulties, m2=moderate motor difficulties.

console=TTY,SPEED
Set the default console to be used with the "live-getty" option. Example:
"console=ttyS0,115200"

debug
Makes initramfs boot process more verbose.
Use: debug=1
Without setting debug to a value the messages may not be shown.

fetch=URL

httpfs=URL
Another form of netboot by downloading a squashfs image from a given url. The fetch
method copies the image to ram and the httpfs method uses fuse and httpfs2 to mount
the image in place. Copying to ram requires more memory and might take a long time for
large images. However, it is more likely to work correctly because it does not require
networking afterwards and the system operates faster once booted because it does not
require to contact the server anymore.
Due to current limitations in busybox's wget and DNS resolution, an URL can not
contain a hostname but an IP only.
Not working: http://example.com/path/to/your_filesystem.squashfs
Working: http://1.2.3.4/path/to/your_filesystem.squashfs
Also note that therefore it's currently not possible to fetch an image from a
namebased virtualhost of an httpd if it is sharing the ip with the main httpd
instance.
You may also use the live iso image in place of the squashfs image.

iscsi=server-ip[,server-port];target-name
Boot from an iSCSI target that has an iso or disk live image as one of its LUNs. The
specified target is searched for a LUN which looks like a live media. If you use the
iscsitarget software iSCSI target solution which is packaged in Debian your ietd.conf
might look like this:
# The target-name you specify in the iscsi= parameter
Target <target-name>
Lun 0 Path=<path-to-your-live-image.iso>,Type=fileio,IOMode=ro
# If you want to boot multiple machines you might want to look at tuning some
parameters like
# Wthreads or MaxConnections

findiso=/PATH/TO/IMAGE
Look for the specified ISO file on all disks where it usually looks for the .squashfs
file (so you don't have to know the device name as in fromiso=....).

fromiso=/PATH/TO/IMAGE
Allows to use a filesystem from within an iso image that's available on live-media.

ignore_uuid
Do not check that any UUID embedded in the initramfs matches the discovered medium.
live-boot may be told to generate a UUID by setting LIVE_GENERATE_UUID=1 when building
the initramfs.

verify-checksums
If specified, an MD5 sum is calculated on the live media during boot and compared to
the value found in md5sum.txt found in the root directory of the live media.

ip=[DEVICE]:[CLIENT_IP]:[NETMASK]:[GATEWAY_IP]:[NAMESERVER]
[,[DEVICE]:[CLIENT_IP]:[NETMASK]:[GATEWAY_IP]:[NAMESERVER]]
Let you specify the name(s) and the options of the interface(s) that should be
configured at boot time. Do not specify this if you want to use dhcp (default). It
will be changed in a future release to mimick official kernel boot param specification
(e.g. ip=10.0.0.1::10.0.0.254:255.255.255.0::eth0,:::::eth1:dhcp).

ip=[frommedia]
If this variable is set, dhcp and static configuration are just skipped and the system
will use the (must be) media-preconfigured /etc/network/interfaces instead.

{live-media|bootfrom}=DEVICE
If you specify one of this two equivalent forms, live-boot will first try to find this
device for the "/live" directory where the read-only root filesystem should reside. If
it did not find something usable, the normal scan for block devices is performed.
Instead of specifing an actual device name, the keyword 'removable' can be used to
limit the search of acceptable live media to removable type only. Note that if you
want to further restrict the media to usb mass storage only, you can use the
'removable-usb' keyword.

{live-media-encryption|encryption}=TYPE
live-boot will mount the encrypted rootfs TYPE, asking the passphrase, useful to build
paranoid live systems :-). TYPE supported so far are "aes" for loop-aes encryption
type.

live-media-offset=BYTES
This way you could tell live-boot that your image starts at offset BYTES in the above
specified or autodiscovered device, this could be useful to hide the Debian Live iso
or image inside another iso or image, to create "clean" images.

live-media-path=PATH
Sets the path to the live filesystem on the medium. By default, it is set to '/live'
and you should not change that unless you have customized your media accordingly.

live-media-timeout=SECONDS
Set the timeout in seconds for the device specified by "live-media=" to become ready
before giving up.

module=NAME
Instead of using the default optional file "filesystem.module" (see below) another
file could be specified without the extension ".module"; it should be placed on
"/live" directory of the live medium.

netboot[=nfs|cifs]
This tells live-boot to perform a network mount. The parameter "nfsroot=" (with
optional "nfsopts="), should specify where is the location of the root filesystem.
With no args, will try cifs first, and if it fails nfs.

nfsopts=
This lets you specify custom nfs options.

nofastboot
This parameter disables the default disabling of filesystem checks in /etc/fstab. If
you have static filesystems on your harddisk and you want them to be checked at boot
time, use this parameter, otherwise they are skipped.

nopersistence
disables the "persistence" feature, useful if the bootloader (like syslinux) has been
installed with persistence enabled.

noeject
Do not prompt to eject the live medium.

ramdisk-size
This parameters allows to set a custom ramdisk size (it's the '-o size' option of
tmpfs mount). By default, there is no ramdisk size set, so the default of mount
applies (currently 50% of available RAM). Note that this option has no currently no
effect when booting with toram.

swapon
This parameter enables usage of local swap partitions.

persistence
live-boot will probe devices for persistence media. These can be partitions (with the
correct GPT name), filesystems (with the correct label) or image files (with the
correct file name). Overlays are labeled/named "persistence" (see
persistence.conf(5)). Overlay image files have extensions which determines their
filesystem, e.g. "persistence.ext4".

persistence-encryption=TYPE1,TYPE2 ... TYPEn
This option determines which types of encryption that we allow to be used when probing
devices for persistence media. If "none" is in the list, we allow unencrypted media;
if "luks" is in the list, we allow LUKS-encrypted media. Whenever a device containing
encrypted media is probed the user will be prompted for the passphrase. The default
value is "none".

persistence-media={removable|removable-usb}
If you specify the keyword 'removable', live-boot will try to find persistence
partitions on removable media only. Note that if you want to further restrict the
media to usb mass storage only, you can use the 'removable-usb' keyword.

persistence-method=TYPE1,TYPE2 ... TYPEn
This option determines which types of persistence media we allow. If "overlay" is in
the list, we consider overlays (i.e. "live-rw" and "home-rw"). The default is
"overlay".

persistence-path=PATH
live-boot will look for persistency files in the root directory of a partition, with
this parameter, the path can be configured so that you can have multiple directories
on the same partition to store persistency files.

persistence-read-only
Filesystem changes are not saved back to persistence media. In particular, overlays
and netboot NFS mounts are mounted read-only.

persistence-storage=TYPE1,TYPE2 ... TYPEn
This option determines which types of persistence storage to consider when probing for
persistence media. If "filesystem" is in the list, filesystems with matching labels
will be used; if "file" is in the list, all filesystems will be probed for archives
and image files with matching filenames. The default is "file,filesystem".

persistence-label=LABEL
live-boot will use the name "LABEL" instead of "persistence" when searching for
persistent storage. LABEL can be any valid filename, partition label, or GPT name.
This option replaces the less flexible persistent-subtext option from version 2 of
live-boot. If you wish to continue using legacy names for persistent storage, use the
full name with this option, e.g. persistence-label=live-rw-foo

quickreboot
This option causes live-boot to reboot without attempting to eject the media and
without asking the user to remove the boot media.

showmounts
This parameter will make live-boot to show on "/" the ro filesystems (mostly
compressed) on "/lib/live". This is not enabled by default because could lead to
problems by applications like "mono" which store binary paths on installation.

silent
If you boot with the normal quiet parameter, live-boot hides most messages of its own.
When adding silent, it hides all.

todisk=DEVICE
Adding this parameter, live-boot will try to copy the entire read-only media to the
specified device before mounting the root filesystem. It probably needs a lot of free
space. Subsequent boots should then skip this step and just specify the
"live-media=DEVICE" boot parameter with the same DEVICE used this time.

toram
Adding this parameter, live-boot will try to copy the whole read-only media to the
computer's RAM before mounting the root filesystem. This could need a lot of ram,
according to the space used by the read-only media.

union=aufs|unionfs
By default, live-boot uses aufs. With this parameter, you can switch to unionfs.

FILES (old)

       /etc/live.conf
           Some variables can be configured via this config file (inside the live system).

       live/filesystem.module
           This  optional  file  (inside  the  live  media)  contains  a  list  of white-space or
           carriage-return-separated file names corresponding  to  disk  images  in  the  "/live"
           directory.  If  this file exists, only images listed here will be merged into the root
           aufs, and they will be loaded in the order listed here. The first entry in  this  file
           will  be the "lowest" point in the aufs, and the last file in this list will be on the
           "top" of the aufs, directly below /overlay.  Without this  file,  any  images  in  the
           "/live" directory are loaded in alphanumeric order.

FILES

       /etc/live/boot.conf

       /etc/live/boot/*

       live/boot.conf

       live/boot/*

       persistence.conf

HOMEPAGE

       More  information about live-boot and the Debian Live project can be found on the homepage
       at <http://live.debian.net/> and in the manual at <http://live.debian.net/manual/>.

BUGS

       Bugs can be reported by submitting a bugreport for the live-boot package in the Debian Bug
       Tracking  System  at  <http://bugs.debian.org/>  or  by  writing a mail to the Debian Live
       mailing list at <debian-live@lists.debian.org>.

AUTHOR

       live-boot was written by Daniel Baumann <daniel@debian.org> for the Debian project.