Replace LXD deb by snap in Ubuntu 18.10

[Stéphane Graber]

Starting with Ubuntu 18.10, LXD will only be distributed as a snap.

Existing users will need to be migrated on upgrade and all reverse dependencies be made aware of the snap.

For those reverse dependencies, make sure that you either:
 - Use the "lxc" and "lxd" commands WITHOUT hardcoding any paths (as they'll now be under /snap/bin/)
 - Use the API and known to look for BOTH /var/lib/lxd/unix.socket and /var/snap/lxd/common/lxd/unix.socket

The "lxd" deb will remain around, so it's fine to still suggest/recommend/depend on it as that'll just install the snap as needed.

[Martin Pitt (pitti)]

autopkgtest *only* uses the `lxc` CLI and documents the `lxd` setup CLI from $PATH. The package has a "Suggests: lxd-client". You mention that the "lxd" deb will remain around, does that apply to "lxd-client" as well?

[Stéphane Graber (stgraber)]

The only binary package left post-transition will be "lxd". The "lxc-client" and "lxd-tools" binary packages will be removed from the archive.

For autopkgtest, it sounds like we'll just need to change the Suggests to point to lxd rather than lxd-client which should be fine even in the current world (as lxd-client alone isn't that useful).

[Martin Pitt (pitti)]

Ah, it used to be useful for running the containers on a remote servers. I. e. what we used to do for armhf testing, they were running on remote arm64 OpenStack instances.

I adjusted the Suggests: https://salsa.debian.org/ci-team/autopkgtest/commit/4d4a7d9b16f

Thanks!

[Stéphane Graber (stgraber)]

Thanks Martin!

[Stéphane Graber (stgraber)]

So looks like we're in good shape with removal of "lxd-client" and "lxd-tools" as only Suggests remains and that's autopkgtest which will be switched over to "lxd" soon enough.

I'm now checking the rdepends of lxd to ensure that they deal with the snap as expected.

[Stéphane Graber (stgraber)]

I've confirmed that adapt from the cosmic archive works just as well with the snap as it does the deb.

[Stéphane Graber (stgraber)]

And confirmed that snapcraft (cleanbuild) similarly works just fine.

[Alex Kavanagh (ajkavanagh)]

From the perspective of nova-lxd, there isn't a problem with the snap version (as pylxd already works with a snap version of lxd). However, the lxd charm will need to be altered to ensure that it installs / otherwise manages the fact that lxd is supplied in snap form.

We do have some utilities to support installation of payloads from snaps, but obviously, this is work that would have to be scheduled. I'll chat in the OpenStack team about this and report back.

[Stéphane Graber (stgraber)]

Ok, going to close the nova-compute-lxd task then as it sounds like from a packaging point of view we're good, it's external integration (charms) that may run into problems.

Note that since we will still have a "lxd" package in the archive which auto-installs the snap for you, things may just work though obviously we'd prefer for the charm to actually install the snap rather than depend on the deb shim.

[Stéphane Graber (stgraber)]

Marking bug as block-proposed so we keep the transitional package in proposed for now.

[Stéphane Graber (stgraber)]

And package has now been uploaded to cosmic-proposed.

[Stéphane Graber (stgraber)]

All autopkgtest failures have been dealt with, we're now all green and only held by this bug's tag.

I intend to clear the tag, allowing for lxd to transition to the release pocket on Monday.

There will likely be a bit of bumpiness afterwards as seeds and meta packages get updated (2-3 hours), then we'll see how the various images behave.

[Stéphane Graber (stgraber)]

As planned, releasing this to the release pocket by removing the blocker tag.

[Launchpad Janitor (janitor)]

This bug was fixed in the package lxd - 1:0.3

---------------
lxd (1:0.3) cosmic; urgency=medium

  * Install the snap on package installation too, not just upgrades
  * Make snapd a Pre-Depends for the case where snapd isn't installed

 -- Stéphane Graber <email address hidden> Thu, 13 Sep 2018 14:28:29 -0400