Agility in Virtualized Utility Computing

Virtual machines have emerged as an attractive approach for utility computing platforms because applications running on VMs are fault- and security-isolated from each other, yet can share physical machines. An important property of a virtualized utility computing platform is how quickly it can react to changing demand. The authors refer to the capability of a utility computing platform to quickly reassign resources as the agility of the platform. They are targeting hosting utility provider environments where the entire platform is under the control of a single administrative domain and application instances often form application-level clusters.