We used Virtuozzos thick-client management console to track the resource usage of our VPSes (virtual private servers).
The product offered us a horde of CPU, storage and memory characteristics to tweak on our guest instances.
We could keep tabs on and manipulate the VPSes wed created without requiring a separate management framework.
We could manage every VPS on our node through Virtuozzos Web console, or delegate admin rights to particular VPSes to certain users.