Date Added: Nov 2011
Computing infrastructure provisioning in Infrastructure as a Service (IaaS) cloud is done in the form of virtual machines. Haizea, a resource lease manager, provides four types of leases: Immediate, Best Effort (BE), Advance Reservation (AR) and Dead Line Sensitive (DLS). AR leases are most privileged leases with "AR preempts other leases" policy, since they can preempt & suspend other BE leases when demanded by consumers. This leads to two problems: a set of BEs can go suspended infinite number of time & ARs, at the actual time of their resource allocation, can be rejected due to presence of other ARs in schedule.