package lxd (not installed) failed to install/upgrade: new lxd package pre-installation script subprocess returned error exit status 1

[Tony Richards]

During do-release-upgrade from Ubuntu 18.0.4 (most recent) to Ubuntu 20.04.2 LTS

During the release upgrade, LXD was upgrading to the snap version 4.16 while I was originally using the dpkg 3.x.

It looks like the upgrade for LXD worked correctly, but lxd-tools couldn't be upgraded because it was looking for lxd (>= 1:0.9) which is no longer installed (because now it's a snap).

ProblemType: Package
DistroRelease: Ubuntu 20.04
ProcVersionSignature: Ubuntu 4.15.0-151.157-generic 4.15.18
Uname: Linux 4.15.0-151-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.11-0ubuntu27.18
Architecture: amd64
CasperMD5CheckResult: skip
Date: Tue Aug 3 14:01:00 2021
ErrorMessage: new lxd package pre-installation script subprocess returned error exit status 1
InstallationDate: Installed on 2020-02-17 (533 days ago)
InstallationMedia: Ubuntu-Server 18.04.3 LTS "Bionic Beaver" - Release amd64 (20190805)
Python3Details: /usr/bin/python3.8, Python 3.8.10, python3-minimal, 3.8.2-0ubuntu2
PythonDetails: /usr/bin/python2.7, Python 2.7.18, python-is-python2, 2.7.17-4
RelatedPackageVersions:
 dpkg 1.19.7ubuntu3
 apt 2.0.6
Snap: lxd 4.16 (latest/stable)
Title: package lxd (not installed) failed to install/upgrade: new lxd package pre-installation script subprocess returned error exit status 1
UpgradeStatus: Upgraded to focal on 2021-08-03 (0 days ago)

[Stéphane Graber (stgraber)]

error: Unable to connect to the source LXD: Get "http://unix.socket/1.0": dial unix /var/lib/lxd/unix.socket: connect: connection refused

This actually suggests a LXD upgrade failure. If this can be reproduce, the output of `journalctl -u snap.lxd.daemon -n 300` would be quite useful.

[Launchpad Janitor (janitor)]

[Expired for lxd (Ubuntu) because there has been no activity for 60 days.]