Novel leases for IaaS cloud

Infrastructure as a Service (IaaS) cloud offers the virtualized resources to the customer in the form of leases. IaaS cloud provider allocates the resources to the leases using various modes such as advance reservation, best effort and immediate. Advance reservation lease requires the resources at a specific time. Best effort lease is placed in a FIFO (first in first out) queue and allocated to resources only when sufficient resources are available. Immediate lease is assigned on its arrival if the resources are available, otherwise it is rejected. Haizea is an open source lease manager that provides these leases by creating virtual machines. However, it is not possible to satisfy the requirements of the leases as no cloud provider has the unlimited resource capacity at a time. In this paper, we propose four new modes of leases, namely period reservation (PR), token reservation (TR), advertisement (AD) and soft and hard deadline (SHD) for the lease managers such as Haizea and Amazon EC2. These modes are more efficient and flexible in contrast to the existing leases. The theoretical analysis clearly shows that the proposed leases outperform the existing leases in terms of cost and acceptance of leases.