Comment 16 for bug 1631104

While working on https://bugs.launchpad.net/ubuntu/+source/openvpn/+bug/1934781, I did face a similar issue.

This was triggered when trying to start openvpn with the openvpn-server@.service unit file in a lxc container fetched from the daily-ubuntu:${series} images.

The error observed was slightly different though:

  openvpn_execve: unable to fork: Resource temporarily unavailable (errno=11)

The error was observed in bionic, focal, and groovy. The error was __not__ observed in hirsute and impish.

The following reports may be relevant here:

https://github.com/systemd/systemd/issues/6011
https://lists.linuxcontainers.org/pipermail/lxc-users/2018-June/014329.html

To verify the issue was indeed not related to a systemd change, I built the openvpn package version available in hirsute for groovy and installed it in my grovy lxc container. This time, I could __not__ observe the issue.

I am attaching a script slightly based on the openvpn autopkgtest suite that can be run from withing a lxc container, which servers as a reproducer for the issue. The script works for anything newer than focal, but would need changes if were to be run in bionic due to recent changes in easy-rsa.