Ok, reviving this conversation!
I ran into the issue that user "mythtv" can not create the file
"/var/run/mythbackend.pid". I see other services that have their pid
file owned by their own user...
Also, user "mythtv" can't write to the log file in /var/log/mythtv/
How do I do this with systemd?
I assume I can update the ownership of /var/log/mythtv during package
install, but I don't know what I can do about /var/run...