I have a server (running Ubuntu 10.04/Zentyal + VirtualBox). It's time is about 5 mins out (it doesn't seem to have any time sync built in).

Hosted on it are two virtual machines, both with accurate times.

One has (in root's crontab): */10 * * * * /usr/sbin/ntpdate -s uk.pool.ntp.org .. so that explains that one being correct.

However the other one does not, and I can't see anything that would be keeping it in sync. I've looked in root's crontab, as well as all of /etc/cron*. There's no ntpd script in /etc/init.d. It's running Ubuntu 11.04 (server).

How would this one be staying correct?