Provided by: open-infrastructure-system-boot_20190301-lts1-2_all bug


       live-boot - System Boot Components


       live-boot  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(7). 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.


       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/*).  These environment
       variables can only be set in the configuration files:

              Disable support for booting from CD-ROMs.  If set to 'y' mkinitramfs will build  an
              initramfs without the kernel modules for reading CD-ROMs.

              Disable  support for booting from FAT file systems.  If set to 'y' mkinitramfs will
              build an initramfs without the kernel module vfat and some nls_* modules.

              Disable  support  for  booting  from  FUSE-based  file  systems.   If  set  to  'y'
              mkinitramfs will build an initramfs without the kernel module fuse and file systems
              that depend on it (like curlftpfs and httpfs2).

              Disable support for booting from NTFS file systems.  If set to 'y' mkinitramfs will
              build an initramfs without the kernel module ntfs.

              Disable support for booting from USB devices.  If set to 'y' mkinitramfs will build
              an initramfs without the kernel module sd_mod.

              Build a minimal initramfs.  If set to  'y'  mkinitramfs  will  build  an  initramfs
              without some udev scripts and without rsync.

              Run  fsck  on  persistence  filesystem  on boot. Will attempt to repair errors. The
              execution log will be saved in /var/log/live/fsck.log.

              If PERSISTENCE_FSCK or forcefsck are set, will pass -y to  fsck  to  stop  it  from
              asking questions interactively and assume yes to all queries.


       live-boot 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.  Example:

           Makes initramfs boot process more verbose.
           Use: debug=1
           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:
           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
           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
           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

           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=....).

           Run fsck on persistence filesystem  on  boot.  Will  attempt  to  repair  errors.  The
           execution log will be saved in /var/log/live/fsck.log.

           Use  a  filesystem  from within an ISO image that's available on live-media. The first
           part of the argument should be the block device where the image is stored, followed by
           the path and filename (e.g. fromiso=/dev/sda1/live/image.iso).
           Alternatively,  it  can  be  used  to  boot  from an ISO embedded into an initrd (e.g.

           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 mimic official kernel boot param  specification
           (e.g. ip=,:::::eth1:dhcp).

           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.

           Override UUID embedded in the initramfs.

           This specific which mount opts to use for mounting live-media.  Default: ro,noatime

           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 specifying 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

           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 "clean" images.

           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.

           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 skipped.

           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 defines 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.

           The  size  of  the  tmpfs mount (used for the upperdir union root mount) in bytes, and
           rounded up to entire pages. This option accepts a suffix % to limit  the  instance  to
           that percentage of your physical RAM or a suffix k, m or g for Ki, Mi, Gi (binary kilo
           (kibi), binary mega (mebi) and binary giga (gibi)). By default, 50% of  available  RAM
           will be used.

           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 ... TYPEn
           This option determines which types of encryption that are  allowed  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".

           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

           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.

           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 media.

           By default, live-boot uses overlay. With this parameter, you can switch to aufs.

FILES (old)

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

           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.













       More information about live-boot and the Live Systems project can be found on the homepage
       at <> and in the manual at <>.


       Bugs  can  be  reported  by  submitting  a  bugreport for the live-boot package in the Bug
       Tracking System at <> or by writing a  mail  to  the  Live  Systems
       mailing list at <>.


       live-boot was written by Daniel Baumann <>.