After I installed Virtualmin GPL on CentOS 7, the host configuration check failed because mailman's qrunner was not running.
Ideally, we need to add a service for systemd. But my very quick makeshift hack was to chmod
/etc/rc.d/rc.local to +x and at the end of it add the following line:
( sleep 60 ; /usr/lib/mailman/bin/mailmanctl start ) &
We need the sleep so mailmanctl won't run until other things are up, otherwise it might not start qrunner. I think it needs networking to be up, and maybe some other things.
The trailing ampersand will put the line into the background and eliminate sixty seconds of boot-time console animations, if you're monitoring the server's console.