Capacity-driven utility model for service level agreement negotiation of cloud services

Dynamic customers' requirements and providers' resources availability in the Cloud market make it inadequate static approaches to guarantee Quality of Service (QoS) levels and to define pricing. In this context, negotiation guided by dynamic information is a viable way to achieve high satisfaction levels for both contract parties. We propose to exploit capacity planning to support bilateral negotiation processes with the aim of optimizing the utility for service providers, by avoiding contracts that could incur in Service Level Agreements (SLAs) violations, keeping, at the same time, competitive prices. The proposed technique exploits a non-additive utility function defined in the region of acceptable SLA proposals, taking into account desired QoS and expected resources availability, costs and penalties. The experimental analysis shows the benefit of the proposed dynamic approach with respect to static ones in a scenario characterized by a set of customers and differentiated classes of applications provided by a cloud environment.