##(see the SpecSpec for an explanation)

 * '''Launchpad Entry''': UbuntuSpec:foundations-o-live-build
 * '''Created''': 2011-05-23
 * '''Contributors''': ColinWatson
 * '''Packages affected''': `livecd-rootfs`, `live-build`

== Summary ==

Ubuntu live CD builds have always been based on an in-house tool called `livecd-rootfs`.  Since we started Ubuntu, Debian has also been working on live CDs, and has a tool called `live-build` which is capable of building Ubuntu images as well.  There is little sense in maintaining two separate tools, so since `live-build` is more flexible we should switch to it.

== Release Note ==

Live CD images are now built using `live-build`, making it easier for users to build customised images.

== Rationale ==

Aside from general flexibility, `live-build` is also used by Canonical's OEM Services team, so switching to it provides internal benefits as well.

== Implementation ==

The main work involved in switching to `live-build` is to analyse the differences between a filesystem image created by `livecd-rootfs` and one created by `live-build` in detail, and reconcile all of them either by adjusting `live-build` configuration, by changing `live-build` itself, or by signing off on the difference as one we don't need to care about.

Following this, we need to invent a way to pass `live-build` configuration across from the `cdimage` builder (because the ISO9660 wrapping will still be done on a single central machine, while live filesystems need to be built on machines of the appropriate architecture), and to run the appropriate build commands.  For the time being, the `BuildLiveCD` script in `livecd-rootfs` will live on as a wrapper script for this, calling `lb config` and `lb build` to do the actual work.  This may change in the future.

The required arguments to `lb config` will reside in `cdimage` code, since updating BuildLiveCD requires a sysadmin RT ticket and it will be useful to have an immediate way to make configuration changes.

=== Outstanding differences ===

(i386, live-build 3.0~a21-1ubuntu1)

Present in livecd-rootfs and not in live-build:

 * /usr/lib/firefox-4.0.1/dictionaries/DicOOo.sxw
 * /usr/lib/firefox-4.0.1/dictionaries/en-GB.aff
 * /usr/lib/firefox-4.0.1/dictionaries/en-GB.dic
 * /usr/lib/firefox-4.0.1/dictionaries/en-US.aff
 * /usr/lib/firefox-4.0.1/dictionaries/en-US.dic

Other changes:

 * /etc/kernel-img.conf shorter in live-build
 * nvidia-common/obsolete-driver not set to false in live-build (why was it?)
 * gettext-base Auto-Installed: 0 in live-build
 * iso-codes Auto-Installed: 0 in live-build
 * libfreetype6 Auto-Installed: 0 in live-build
 * libfuse2 Auto-Installed: 0 in live-build
 * linux-headers-2.6.38-8 Auto-Installed: 1 in livecd-rootfs
 * linux-headers-2.6.38-8-generic Auto-Installed: 1 in livecd-rootfs
 * uuid-runtime Auto-Installed: 0 in live-build

=== Signed-off differences ===

(i386, live-build 3.0~a21-1ubuntu1)

Present in live-build and not in livecd-rootfs:

 * /etc/adjtime
 * /etc/resolv.conf (empty, so harmless)

Present in livecd-rootfs and not in live-build:

 * /etc/apt/trusted.gpg~
 * /etc/group-
 * /etc/gshadow-
 * /etc/hosts
 * /etc/shadow-
 * /etc/udev/rules.d/70-persistent-net.rules
 * /var/lib/dpkg/available-old
 * /var/lib/dpkg/diversions-old
 * /var/lib/dpkg/statoverride-old
 * /var/lib/dpkg/status-old
 * /var/log/apt/term.log

Other changes:

 * /etc/apt/sources.list rather shorter in live-build
 * /etc/hostname is localhost.localdomain in live-build
 * different set of updates applied
 * debconf/frontend not marked seen in live-build
 * dictionaries-common/default-wordlist marked seen in live-build (don't care?)
 * lots of English locales added to /var/lib/belocs/hashfile in live-build
 * zh_CN.utf8, zh_SG.utf8 added to /var/lib/belocs/list in live-build
 * linux-image-2.6.38-8-generic, linux-base removed from /var/run/reboot-required.pkgs in live-build

----
 CategorySpec