I have recently much trouble with services started by upstart. Currently I have problems with avahi-daemon and rsyslogd. Most of the time i had that problem on Ubuntu >= 12.04.
What's the problem? If I stop such a service, the stop-script hangs (waited 2 day on one server). When I kill it the service remains in the following state
stop/killed, process <pid> which is undocumented (just
stop/killed is documented!). The service really is down.
Now when I try to start the service with
service <service> start again the start script hangs, too.
My question to that is: How shall I debug such problems? The start/stop scripts just do nothing at a point and it is intranparent to me what causes this. I even had that problem with the unattended-upgrades