Admission Control for Elastic Cloud Services

This paper presents an admission control test for deciding whether or not it is worth to admit a set of services into a Cloud, and in case of acceptance, obtain the optimum allocation for each of the components that comprise the services. In the proposed model, the focus is on hosting elastic services the resource requirements of which may dynamically grow and shrink, depending on the dynamically varying number of users and patterns of requests. In finding the optimum allocation, the presented admission control test uses an optimization model, which incorporates business rules in terms of trust, eco-efficiency and cost, and also takes into account affinity rules the components that comprise the service may have. The proposed approach also allows for partial acceptance of a service and possible federation with other Cloud providers. By incorporating a probabilistic approach that relies on the actual probabilities of requiring extra elastic computing and networking capacity for the services at runtime, the model reduces the physical resources that need to be booked for elasticity reasons by promoting the allocation of more services on already used physical hosts. The output of the admission control test is the set of accepted services, and the allocated computing and networking capacity for the components that comprise them on the selected physical hosts and subnets. The problem was modeled on the General Algebraic Modeling System (GAMS) and solved under realistic provider’s settings that demostrate the efficiency of the proposed method.