Service level agreements (SLAs) are one of the major considerations for every buyer of cloud computing services. Finding the SLA truth, and whether a service provider will meet your requirements, depends on the details of how they define their SLA measures and penalties. Our study indicates that none of the surveyed cloud providers offer any performance guarantees for compute services and leave SLA violation detection to the customer. We then provide guidance on how SLAs should be defined for future cloud services. This paper surveys the state of practice in service level agreement specification and offers guidelines on how to assure that services are provided with high availability, security, performance, and other required qualities. In addition, this paper discusses the quality properties that have been expressed in service level agreements.
Cloud computing, SLA, SOA
