VeloZ: A Charging Policy Specification Language for Infrastructure Clouds

Cloud Accounting refers to how cloud usage is recorded and charged. It is present at all commercialized cloud services (SaaS, PaaS and IaaS), since they have to monitor the consumption aiming to charge the customers. In a previous research we performed a systematic mapping study regarding cloud accounting and identified a set of shortcomings in the existing accounting models for IaaS. One of these limitations was related to charging policy specification. Charging policies are mechanisms that establish rules to convert usage records into monetary information. This paper presents a Domain Specific Language (DSL) for charging policy specification: VeloZ. Such DSL enables cloud providers to write charging policies following the economic model RaaS. According to RaaS, the IaaS must be provisioned in a high granularity in terms of resource types and such granularity is profitable for both, provider and customer. We evaluated the DSL under a real cloud platform called JiTCloud. The experiment results evidences that VeloZ can be considered feasible in terms of flexibility and reliability.