Note: The VM2 codename has been retired and the product this document describes is now known as Cloudmin.
VM2 (or Virtualmin Machine Manager to use its full name) is a powerful tool for managing multiple systems from a single web interface. It is typically used in conjunction with Virtualmin, to make the management of virtual domains across several systems easier. It can also be used to create and maange virtual systems using technologies like Xen, Linux VServers, Solaris Zones and Amazon's EC2 service.
VM2 is built on top of Webmin, and is implemented as a Webmin module with a similar interface to that provided by Virtualmin. When using it to manage virtual systems, it has a three-layer architecture :
VM2 Master System This is the system that runs Webmin with the VM2 module installed, to which you connect with your browser. All virtual system management is done on the master, which communicates with other managed systems using SSH and Webmin's RPC protocol.
Virtual System Hosts These are the machines that host Xen, VServers or Zones instances. They will not typically be used for any other purpose, and only need to have Webmin and the software needed for virtual system hosting installed.
Virtual System Instances These are the virtual private servers running inside Xen, VServers or Zones instances. Typically each will have a full Virtualmin software stack installed, which includes Apache, Postfix, MySQL and Webmin. They can then be used to host websites and email domains, just like real systems .. but have the advantage that they can be created on demand.
VM2 can also be used in environments that do not use any kind of virtual system technology, to manage many real machines with Virtualmin installed. In this case, the second layer above is effectively removed.
See the pages below for more information on what VM2 does and how to use it :