  Modern day continued demand for resource hungry services and applications in
IT sector has led to development of Cloud computing. Cloud computing
environment involves high cost infrastructure on one hand and need high scale
computational resources on the other hand. These resources need to be
provisioned (allocation and scheduling) to the end users in most efficient
manner so that the tremendous capabilities of cloud are utilized effectively
and efficiently. In this paper we discuss a selective algorithm for allocation
of cloud resources to end-users on-demand basis. This algorithm is based on
min-min and max-min algorithms. These are two conventional task scheduling
algorithm. The selective algorithm uses certain heuristics to select between
the two algorithms so that overall makespan of tasks on the machines is
minimized. The tasks are scheduled on machines in either space shared or time
shared manner. We evaluate our provisioning heuristics using a cloud simulator,
called CloudSim. We also compared our approach to the statistics obtained when
provisioning of resources was done in First-Cum-First- Serve(FCFS) manner. The
experimental results show that overall makespan of tasks on given set of VMs
minimizes significantly in different scenarios.
