REST-Based SLA Management for Cloud Applications

In cloud computing, possible risks linked to availability, performance and security can be mitigated by the adoption of Service Level Agreements (SLAs) formally agreed upon by cloud service providers and their users. This paper presents the design of services for the management of cloud-oriented SLAs that hinge on the use of a REST-based API. Such services can be easily integrated into existing cloud applications, platforms and infrastructures, in order to support SLA-based cloud services delivery. After a discussion on the SLA life-cycle, an agreement protocol state diagram is introduced. It takes explicitly into account negotiation, remediation and renegotiation issues, is compliant with all the active standards, and is compatible with the WS-Agreement standard. The requirement analysis and the design of a solution able to support the proposed SLA protocol is presented, introducing the REST API used. This API aims at being the basis for a framework to build SLA-based applications.