Did a "do-release-upgrade" from 18.04 to 20.04 and got an error message

[Peter Klaesson]

I ran do-release-upgrade -d on a Ubuntu 18.04 server system.

I got an error message after being prompted that LXD from now on is managed using snap.

Was running 3.0 using apt in 18.04, chose to track LXD 4.0 in do-release-upgrade.

Got an error message.

Expected to not be prompt to file a bug report.

When do-release-upgrade was finished it said "The upgrade has completed but there were errors during the upgrade process."

ProblemType: Package
DistroRelease: Ubuntu 20.04
Package: lxd 3.0.3-0ubuntu1~18.04.1
ProcVersionSignature: Ubuntu 5.3.0-40.32~18.04.1-generic 5.3.18
Uname: Linux 5.3.0-40-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.9-0ubuntu7.14
Architecture: amd64
Date: Fri Apr 24 20:09:09 2020
ErrorMessage: new lxd package pre-installation script subprocess returned error exit status 126
InstallationDate: Installed on 2016-04-28 (1456 days ago)
InstallationMedia: Ubuntu-Server 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.3)
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 2.0.2
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 126
UpgradeStatus: Upgraded to focal on 2020-04-24 (0 days ago)

[Peter Klaesson (alphapeter)]

I manage to figure out what was wrong.

I found out that snapd had stuck on auto-refresh "core", (ran sudo snap changes). It was stuck since yesterday. Thus the lxd snap broke when installed.

What I did to fix it.
* Aborted the autorefresh (sudo snap abort <id>)
* stopped the snapd service (had to kill all the snapd processes)
* started snapd again
The first time when snapd restarted, it got stuck again.

Once again...
* Aborted the autorefresh (sudo snap abort <id>)
* stopped the snapd service (had to kill all the snapd processes)
* started snapd again
* Ran sudo snap connect lxd:lxd-support core:lxd-support (to fix the broken lxd snap)

Then I ran apt-get install lxd again... and it got stuck, could not terminate the previous lxd service.

* Had to force reboot the computer.

After a restart.

Ran apt-get install lxd again and everything worked as expected.

To continue continue the upgrade, I ran sudo apt upgrade.

Now everything is OK

So, summary. If the snap auto-refresh of "core" is stuck. The upgrade will fail.
Maybe a pre-check that the "core" snap is enabled before starting the release-upgrade (at least if lxd is installed)?

[Stéphane Graber (stgraber)]

Thanks for your analysis, I've re-targeted to snapd as that's not expected behavior from it.

[Rabi C (rabic)]

I had the same issue:
When the Package Configuration dialog came up on Configuring lxd
LXD snap track latest/3.0/4.0
When I chose 4.0 and proceed, the installation hung indefinitely at
==> Installing the LXD snap from the 4.0 track for ubuntu-20.04

My workaround was to do the following at the point the Configuration dialog showed up in seperate shell:
sudo snap install hello-world
sudo snap list

Then proceed with Configuring lxd. The installation proceeded and did not hang at the Installing LXD snap point
$ sudo snap list
[sudo] password for pos:
Name Version Rev Tracking Publisher Notes
core 16-2.44.3 9066 latest/stable canonical* core
core18 20200427 1754 latest/stable canonical* base
hello-world 6.4 29 latest/stable canonical* -
lxd 4.0.1 14890 4.0/stable/… canonical* -

[Samuele Pedroni (pedronis)]

seems the release upgrade needs to check whether snapd is ready to help through an upgrade, there might be a need for snap to help in that

[Al Hazred (therealhazzard)]

I have the same issue as well.

> When the Package Configuration dialog came up on Configuring lxd
> LXD snap track latest/3.0/4.0
> When I chose 4.0 and proceed, the installation hung indefinitely at
> ==> Installing the LXD snap from the 4.0 track for ubuntu-20.04

[Al Hazred (therealhazzard)]

Sorry, actually after I let it run longer it finished. But it didn't show any progress or any indication something was happening.