Errors while updating fresh Ubuntu 20.04 to Ubuntu 22.04 on a VDS

[Egor Suvorov]

I've just got a fresh VDS with Ubuntu 20.04.1 LTS (they system may be modified by the hoster, though). I then set up SSH server, `sudo apt update && sudo apt upgrade` followed by `sudo do-dist-upgrade`. Unfortunately, the upgrade had some errors:

```
Errors were encountered while processing:
 udev
 initramfs-tools-core
 initramfs-tools
 plymouth
 plymouth-theme-ubuntu-text
 grub-common
 os-prober
 grub2-common
 grub-pc-bin
 grub-pc
Exception during pm.DoInstall(): E:Sub-process /usr/bin/dpkg returned an error code (1)

Could not install the upgrades

The upgrade has aborted. Your system could be in an unusable state. A
recovery will run now (dpkg --configure -a).

Please report this bug in a browser at
http://bugs.launchpad.net/ubuntu/+source/ubuntu-release-upgrader/+filebug
and attach the files in /var/log/dist-upgrade/ to the bug report.
E:Sub-process /usr/bin/dpkg returned an error code (1)

...

Upgrade complete

The upgrade has completed but there were errors during the upgrade
process.

To continue please press [ENTER]
```

Nonetheless, it seems that the upgrade was completed, `lsb_release -rd` is now 22.04. However, `sudo reboot` printed:

```
Failed to open initctl fifo: No such device or address
Failed to talk to init daemon.
```

I hard-rebooted the server and now `sudo reboot` works as expected.