IAAS-04: Request and use a virtual cluster

Executive Summary: 
A researcher obtains exclusive access to a virtual cluster (a predefined suite of hosted computer systems and/or storage volumes) with expert assistance by a service provider.
User Importance Summary: 
Researchers are increasingly using externally hosted ("cloud") virtual machines to extend their computing environments without requiring capital investment.
Target Communities and Sizes: 
Researchers - O(1000) Science gateways - O(10)