Comment 18 for bug 1162475

I don't think it's *-control-center.

At the time, that was filed there by pitti, who correctly pointed out that something might need to depend on libnss-myhostname (from systemd) for a fallback to resolving hostname via just /etc/hostname (since /etc/hosts isn't changed). At this point though, it looks like this is no longer required.

Now, AFAICT the desktop correctly calls to systemd via dbus to ask for the change. I'll leave to you to make sure this is indeed the case (since you had commented on the bug previously, and I can't see any issues changing hostname as it is now, but maybe I'm not quite doing the same tests you were).

unity-control-center is an obvious Won't Fix for Eoan or Disco, but I'll let the Desktop Team decide whether this needs to be fixed in other releases.

Finally, this is still assigned to systemd, low priority, because hostnamed *doesn't* change /etc/hosts, and probably should (at the very least for consistency, to avoid keeping a reference to an old name for the system); but I didn't notice ill effects from not changing that file. sudo certainly doesn't hang here trying to resolve the new or old hostname.