What is the update procedure?

AFAIK, use the Webmin module update. It should update like any other module in Webmin.

We may not have made a version of the Virtualmin Package Updates module for Cloudmin yet. I'll ask Jamie. If not, it'll be out in a day or two...there have been no updates to Cloudmin yet, so nothing to update at the moment. ;-)

You can always use yum or apt-get for regular system updates, as well. And, if you're using our yum repo (apt-get repo coming soon), you'll be able to use it for updates to Cloudmin packages, too.