LXD appliance image needs to follow the 4.0 track

[Łukasz Zemczak]

[Impact]

Per definition of the appliance, we need to follow the 4.0 LTS track instead of 'latest', which is default. I originally assumed that the model assertion will be self-contained and has everything that's needed, but it seems that required-snaps for UC18 are not allowed to have custom tracks set (this is only supported for UC20).
So to make things work, we need to work-around it by adding the custom lxd snap track via livecd-rootfs.

[Test Case]

Perform a -proposed enabled ubuntu-appliance cdimage build for the lxd appliance and confirm via the manifest that the lxd snap is taken from the right track.

[Regression Potential]

If anything, all possible regressions are in ubuntu-core image builds, like invalid extra snaps could be installed or the builds could start failing.

[Timo Aaltonen (tjaalton)]

Hello Łukasz, or anyone else affected,

Accepted livecd-rootfs into bionic-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/livecd-rootfs/2.525.47 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, what testing has been performed on the package and change the tag from verification-needed-bionic to verification-done-bionic. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-bionic. In either case, without details of your testing we will not be able to proceed.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance for helping!

N.B. The updated package will be released to -updates after the bug(s) fixed by this package have been verified and the package has been in -proposed for a minimum of 7 days.

[Łukasz Zemczak (sil2100)]

Ran a PROPOSED=1 ubuntu-appliance image of the lxd appliance and confirmed via the manifest that the correct lxd version has been used. The build can be seen here:

https://launchpad.net/~ubuntu-cdimage/+livefs/ubuntu/bionic/ubuntu-core/+build/234364

livecd-rootfs version used was 2.525.47.

[Launchpad Janitor (janitor)]

This bug was fixed in the package livecd-rootfs - 2.525.47

---------------
livecd-rootfs (2.525.47) bionic; urgency=medium

  * Apparently the lxd appliance needs to use a custom track (4.0) and since
    model assertions do not accept track names in required-snaps, we need to do
    this by hand during build. (LP: #1891505)

 -- Łukasz 'sil2100' Zemczak <email address hidden> Wed, 12 Aug 2020 15:58:19 +0200

[Brian Murray (brian-murray)]

The verification of the Stable Release Update for livecd-rootfs has completed successfully and the package is now being released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regressions.