Architectural Design of a Compensation Mechanism for Long Lived Transactions

Together with making Cloud computing reliable and dependable, there is a need to create mature definition of Service Level Agreements (SLA) for the quality assurances of services. Additionally, it is necessary to implement certain mechanisms in order to maintain the SLA further. In particular, the inter-Cloud environment with multiple entities of Cloud computing has evolved. In order to realize the inter-Cloud environment, the Composite Web Service (CWS) is a promising candidate. However, the CWS which consists of multiple elemental services has features of a transactional workflow adopting the notion of a long lived transaction (LLT). A compensation transaction is required for handling the occurrence of an exception. However its design methodology has remained immature. In particular, clarifying a concrete architecture for integrating Transaction-Aware together with the mechanism for maintaining SLA categorized as QoS-Aware has been ongoing. In this paper, we present our initial consideration on the architectural design and its principle for SLA management which carries out the compensations. The architectural aspects for an intelligent function which is required in the next scalable workflow will also be presented.