systemd unit starts too soon - conflicts with openvpn

[Daniel Miller]

Ubuntu Bionic - 18.04.1

Having previously installed & configured openvpn-server I recently installed quagga-ospfd & quagga-core. A reboot then showed OpenVPN server wouldn't start - the TUN device of my config was not created - I later found the error "RTNETLINK answers: File exists". Stopping ospfd & zebra then allowed openvpn to start without issue.

The packaged systemd units for the quagga services include:
   Before=network.target
   After=network-pre.target

Yet openvpn-server@ has
  After=network-online.target
  Wants=network-online.target

I modified the quagga units by removing the "Before=" lines and adding After="openvpn-server@<myvpn>.service". It would probably be better to have an openvpn-server.target defined that references the template openvpn-server@.service and use that target for the quagga After= reference.

[Christian Ehrhardt  (paelzer)]

Hi,
In general I first have to agree that the openvpn services are a bit of a mess.
The deduplication of the openvpn services is a known and ongoing issue [1].
That requires to merge both of them and create sort of a best of both worlds approach.

I'll set my coworker who will work on that to CC here to be aware.

But for the suggested openvpn-server.target that would be referred to from quagga as After= I'm not so sure. I think that only reflects your use case of it.
I'd think there can be people using quagga without openvpn (not so bad since After is only an ordering dependency) or even people that have openvpn but want it to come up after quagga as they'd want some routing updates done before openvpn works.

I'm not entirely sure, but no matter where this goes in detail - the openvpn services need to be cleaned up before that, because only then can we make safe assumptions about their behavior.

[1]: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=866523