ubuntu server 18.04.1 session hangs when updating systemd via ssh session via a route configured by policy routing

[Uli.Heller]

I have installed ubuntu server 18.04 on one of my machines.
I can access the machine only via ssh.

Typically, I run these commands from time to time:

- ssh root@{machine}
- apt-get update
- apt-get upgrade

I observed at least two times now that "apt-get upgrade" doesn't complete. It hangs
on this:

  ...
  Vorbereitung zum Entpacken von .../libudev1_237-3ubuntu10.11_amd64.deb ...
  Entpacken von libudev1:amd64 (237-3ubuntu10.11) über (237-3ubuntu10.9) ...
  libudev1:amd64 (237-3ubuntu10.11) wird eingerichtet ...
  systemd (237-3ubuntu10.11) wird eingerichtet ...

The ssh session becomes unresponsive.

I am not able to ssh from my desktop into the machine again.
I have to ssh into a neighbor of the machine running within the same subnet. From that, I
could ssh into the machine and run "netplan apply". Afterwards, everything is fine.

Please note that I do use policy routing.

Before "netplan apply":
  root@samson:~# ip rule list
  0: from all lookup local
  32766: from all lookup main
  32767: from all lookup default

After "netplan apply":
  root@samson:~# ip rule list
  0: from all lookup local
  0: from {ip-address} lookup 120
  0: from all to {ip-address} lookup 120
  32766: from all lookup main
  32767: from all lookup default

[Ubuntu Foundations Team Bug Bot (crichton)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. It seems that your bug report is not filed about a specific source package though, rather it is just filed against Ubuntu in general. It is important that bug reports be filed about source packages so that people interested in the package can find the bugs about it. You can find some hints about determining what package your bug might be about at https://wiki.ubuntu.com/Bugs/FindRightPackage. You might also ask for help in the #ubuntu-bugs irc channel on Freenode.

To change the source package that this bug is filed about visit https://bugs.launchpad.net/ubuntu/+bug/1811348/+editstatus and add the package name in the text box next to the word Package.

[This is an automated message. I apologize if it reached you inappropriately; please just reply to this message indicating so.]

[Dan Streetman (ddstreet)]

please reopen if this is still an issue