Modelling and comparing cloud computing service level agreements

Service-level agreements are a critical mechanism underpinning the pay-per-consumption model of business for cloud computing. Cloud providers make a variety of services of different qualities available on-demand for consumers. However, there is no standard ontology, vocabulary, or set of mechanisms that can be used for systematically and semi-automatically expressing and comparing cloud SLAs. We report on research investigating the use of MDE principles and technologies for making cloud SLAs easier to write, use and semi-automatically compare by domain experts. Our ultimate objective is to make it easier for non-experts to take decisions by programmatically comparing different cloud SLAs. We propose a metamodel for both cloud consumer requirement and cloud provider SLAs, and exploit model comparison technology for automating the comparison process.