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

[Marius Gedminas]

This looks like a network error:

    Download snap "snapd" (9279) from channel "stable" (received an unexpected http response code (503) when trying to download https://api.snapcraft.io/api/v1/snaps/download/PMrrV4ml8uWuEUDBT8dSGnKUYbevVhc4_9279.snap)

that happened during do-release-upgrade from 18.04 to 20.04, but the consequence is that the entire upgrade is now considered to be failed and I have to pick up the pieces manually.

ProblemType: Package
DistroRelease: Ubuntu 20.04
Package: lxd 3.0.3-0ubuntu1~18.04.1
ProcVersionSignature: Ubuntu 4.15.0-118.119-generic 4.15.18
Uname: Linux 4.15.0-118-generic x86_64
ApportVersion: 2.20.11-0ubuntu27.9
Architecture: amd64
CasperMD5CheckResult: skip
Date: Wed Sep 30 17:25:44 2020
Ec2AMI: ami-0001c5ea
Ec2AMIManifest: FIXME
Ec2AvailabilityZone: nova
Ec2InstanceType: vps-ovhssd2018-1
Ec2Kernel: unavailable
Ec2Ramdisk: unavailable
ErrorMessage: new lxd package pre-installation script subprocess returned error exit status 1
Python3Details: /usr/bin/python3.8, Python 3.8.2, python3-minimal, 3.8.2-0ubuntu2
PythonDetails: /usr/bin/python2.7, Python 2.7.18rc1, python-is-python2, 2.7.17-4
RelatedPackageVersions:
 dpkg 1.19.7ubuntu3
 apt 2.0.2ubuntu0.1
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 2020-09-30 (0 days ago)