So I faced a little challenge with a Zentyal server the other day. I was upgrading from ye olde 6.0 to 6.1, when everything just stopped. I let it sit in the corner for about an hour or so, but it never picked up the thread. All the services were still live, so I logged in to have a look.
(Note, my DNS server is named RIMU; yours may be something else!)
ps aux, I discovered this line:
sh -c /usr/bin/sudo -p sudo: /var/lib …