Attempt to upgrade from Ubuntu 18.10 (cosmic)

[Arkadi Kagan]

This computer was turned off for about half year or more.
From that time on I can't do a normal upgrade to next Ubuntu.

Since I could not install anything and I have had a work to do, I did a manual upgrade of
  /etc/apt/sources.list
to point on "eoan" instead of "cosmic".
That helped to install some programs.

However, do-release-upgrade is still failing.
Tried a workaround in
   https://nelsonslog.wordpress.com/2020/02/21/upgrading-from-an-unsupported-ubuntu/
It still crashes.

ProblemType: Bug
DistroRelease: Ubuntu 19.10
Package: ubuntu-release-upgrader-core 1:19.10.15.4
ProcVersionSignature: Ubuntu 5.3.0-64.58-generic 5.3.18
Uname: Linux 5.3.0-64-generic x86_64
ApportVersion: 2.20.11-0ubuntu8.9
Architecture: amd64
CrashDB: ubuntu
Date: Sun Aug 23 00:09:50 2020
InstallationDate: Installed on 2018-11-23 (638 days ago)
InstallationMedia: Ubuntu 18.10 "Cosmic Cuttlefish" - Release amd64 (20181017.3)
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to eoan on 2020-08-22 (0 days ago)
VarLogDistupgradeAptlog:
 Log time: 2020-08-23 00:09:17.036708
 Log time: 2020-08-23 00:09:24.340283
 Log time: 2020-08-23 00:09:42.873568
 Log time: 2020-08-23 00:09:57.162623

[Arkadi Kagan (arkadi-kagan)]

I don't see it as a duplicate of bug #1813354, unless all upgrade bugs are the same.

Anyway, key work-around was indeed here:
    https://nelsonslog.wordpress.com/2020/02/21/upgrading-from-an-unsupported-ubuntu/

So my solution was like this:
- I started with 18.10
- Call do-release-upgrade
- Update /usr/lib/python3/dist-packages/UpdateManager/Core/MetaRelease.py
    self.metarelease_information = open(self.METARELEASE_FILE, "r")
into
    self.metarelease_information = open(self.METARELEASE_FILE + "2", "r")
It will be reverted by last step (real upgrade)
- Create /var/lib/update-manager/meta-release2, copy of meta-release
- In that file mark "disco" as supported
- Update /etc/apt/sources.list
   all "cosmic" to "eoan"
- Call do-release-upgrade
    There where some errors, but system "About" shows "19.10" after that
- Edit again /etc/apt/sources.list
   all "eoan" become "focal"
- Call do-release-upgrade
    real upgrade is happening, according to (long) time that it takes
Now the system is "20.04" and I see some graphical changes.
I suppose all is fine now.

This system is a physical machine, so I can't repeat all the process to filter out unneeded steps.

[Arkadi Kagan (arkadi-kagan)]

It's nice to have work-around.
However, do-release-upgrade is expected to work, even if that system was offline for some long period of time.

[Brian Murray (brian-murray)]

This is a duplicate of bug 1813354 because we can see in VarLogDistupgradeMainlog.txt your sources.list entry contained entries like 'deb mirror://mirrors.ubuntu.com/mirrors' for the eoan release of Ubuntu. Bug 1813354 is about those entries being unsupported.