package lxd 3.0.3-0ubuntu1~18.04.1 failed to install/upgrade: new lxd package pre-installation script subprocess returned error exit status 1

[William Kenworthy]

Occurred while upgrading to LTS 20

ProblemType: Package
DistroRelease: Ubuntu 20.04
Package: lxd 3.0.3-0ubuntu1~18.04.1
ProcVersionSignature: Ubuntu 4.15.0-128.131-generic 4.15.18
Uname: Linux 4.15.0-128-generic x86_64
ApportVersion: 2.20.11-0ubuntu27.14
Architecture: amd64
CasperMD5CheckResult: skip
Date: Sat Dec 26 20:41:10 2020
Ec2AMI: ami-ea87a78f
Ec2AMIManifest: (unknown)
Ec2AvailabilityZone: us-east-2c
Ec2InstanceType: t2.small
Ec2Kernel: unavailable
Ec2Ramdisk: unavailable
ErrorMessage: new lxd package pre-installation script subprocess returned error exit status 1
Python3Details: /usr/bin/python3.8, Python 3.8.5, 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 2.0.2ubuntu0.2
SourcePackage: lxd
Title: package lxd 3.0.3-0ubuntu1~18.04.1 failed to install/upgrade: new lxd package pre-installation script subprocess returned error exit status 1
UpgradeStatus: Upgraded to focal on 2020-12-26 (0 days ago)
modified.conffile..etc.apparmor.d.usr.lib.lxd.lxd-bridge-proxy: [deleted]

[Stéphane Graber (stgraber)]

- Run install hook of "lxd" snap if present (run hook "install": /var/lib/snapd not root-owned 0:110)

That's a new one I've never seen before. This suggests that directory ownership for /var/lib/snapd is quite wrong on your system which in turn causes some snapd actions to fail.

I'll re-assign to snapd for investigation but it'd be useful if you could show `ls -lh /var/lib/` to see what's going on there.