[systemd-devel] Reliable way to finish system units before termination through systemd shutdown / reboot routines

[Reiner Wenke]

Hello,

I have running some virtualbox instances under systemd control and use vboxautostart-service
for starting and stopping (saving). This is running on Centos7
As long as I use systemctl stop vboxautostart-service for termination, everything is fine, 
but it takes some time for completion.

If I shutdown or reboot the host system, then I get a premature kill of all running instances,
most likely through the systemd reboot / shutdown routines .
I tried some configuration changes, but nothing worked for me.

Is there a reliable way to avoid this behavior?

Best regards
Reiner