An embodiment of a method of forming a virtual computer cluster within a shared computing environment begins with a step of placing gatekeeper software on each of a plurality of particular host computers of the shared computing environment. The method continues with a step of assigning computing platforms located on the particular host computers to the virtual computer cluster. The gatekeeper software interposes between the computing platforms and hardware resources of the particular host computers. The method concludes with a step of isolating the virtual computer cluster from a remainder of the shared computing environment using the gatekeeper software. The gatekeeper software allows communication between the computing platforms while precluding communication with other computing platforms of the shared computing environment. The gatekeeper software controls input and output operations for the virtual computer cluster.