I recently installed Cloudmin GPL alongside my existing Virtualmin GPL installation, and think I've found a bug.
When I create a XEN machine, one of the steps is to regenerate the SSH keys, which are then stored on the Cloudmin Master in /root/.ssh/known_hosts. Now, I would assume that when regenerating, it should replace the previous key for the image (which it seems to add at the very beginning of the creation), but instead it adds a second key, thus causing SSH connections to the XEN guest to fail with the NO SSH error. I have to manually remove all entries, and then tell it to clear the ssh keys to sucessfully gain SSH access.
Also, when removing a guest, it doesn't remove the keys, which would be helpful, in case you attempt to re-add a guess with the same IP as the old one.
PS. Running on Ubuntu 8.04 64-bit, latest updates for both the system, Webmin, Usermin, Virtuamin and . I can provide any logs, etc upon request