1. A method of forming a virtual computer cluster within a shared computing environment comprising the steps of: placing gatekeeper software on each of a plurality of particular host computers of the shared computing environment; assigning computing platforms located on the particular host computers to the virtual computer cluster such that the gatekeeper software interposes between the computing platforms and hardware resources of the particular host computers; and isolating the virtual computer cluster from a remainder of the shared computing environment using the gatekeeper software such that the gatekeeper software allows communication between the computing platforms while precluding communication with other computing platforms of the shared computing environment and such that the gatekeeper software controls input and output operations for the virtual computer cluster.