- System Boot Components
contains the components that configure a 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
This includes the Live systems ISOs, netboot tarballs, and usb stick images.
At boot time it will look for a (read-only) medium 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, to boot the system from.
can be configured through a boot parameter or a configuration
To configure the live-boot parameters used by default in a live image, see the
--bootappend-live option in the lb_config(1)
is only activated if 'boot=live' was used as a kernel
In addition, there are some more boot parameters to influence the behaviour, see
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,
currently features the following parameters.
- 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.
- Set the default console to be used with the "live-getty" option.
- Makes initramfs boot process more verbose.
Without setting debug to a value the messages may not be shown.
- 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 address only.
Not working: http://example.com/path/to/your_filesystem.squashfs
Also note that therefore it's currently not possible to fetch an image from
a name-based virtualhost of an httpd if it is sharing the IP address with
the main httpd instance.
You may also use the live ISO image in place of the squashfs image.
- 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
medium. If you use the iscsitarget software iSCSI target solution
your ietd.conf might look like this:
# The target-name you specify in the iscsi= parameter
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
- 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
- Allows to use a filesystem from within an ISO image that's available on
- 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.
- 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.
- 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.
- If this variable is set, dhcp and static configuration are just skipped
and the system will use the (must be) media-preconfigured
- 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-boot will mount the encrypted rootfs TYPE, asking the passphrase,
useful to build paranoid live systems :-). TYPE supported so far is
"aes" for loop-aes encryption type.
- 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 live system ISO or image inside another ISO or image, to create
- 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
- Set the timeout in seconds for the device specified by
"live-media=" to become ready before giving up.
- 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.
- 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.
- This lets you specify custom nfs options.
- 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
- disables the "persistence" feature, useful if the bootloader
(like syslinux) has been installed with persistence enabled.
- Do not prompt to eject the live medium.
- This parameter 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 currently no effect when booting with toram.
- This parameter enables usage of local swap partitions.
- 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 are named "persistence".
- persistence-encryption=TYPE1,TYPE2 ...
- 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
- 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
- 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
- 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
- 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".
- 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 causes live-boot to reboot without attempting to eject the
media and without asking the user to remove the boot media.
- 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.
- If you boot with the normal quiet parameter, live-boot hides most messages
of its own. When adding silent, it hides all.
- 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.
- 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
- By default, live-boot uses overlay. With this parameter, you can switch to
- Some variables can be configured via this config file (inside the live
- 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
More information about live-boot and the Live Systems project can be found on
the homepage at < http://live-systems.org/
> and in the manual at
Bugs can be reported by submitting a bugreport for the live-boot package in the
Bug Tracking System at < http://bugs.debian.org/
> or by writing a
mail to the Live Systems mailing list at <
live-boot was written by Daniel Baumann <