It looks like both upstart and systemd don't provide direct mechanisms to
manage all instances.
That's true (I'm only speaking about systemd). There have been requests for
such functionality before, but nothing was implemented. But I think we should
revisit this topic... I recently added globbing to a bunch of systemctl verbs
for listing stuff (list-units, list-sockets, etc.), and it was actually
trivial. I felt that allowing globing for verbs that influence state (start,
stop, enable, disable, ...) was too dangerous. But this should be safe for
instance units, so I'd like to see 'systemctl stop/status/... server@*.service'
implemented.
Zbyszek