OSIRIS-SR: a safety ring for self-healing distributed composite service execution

The advent of service-oriented architectures has strongly facilitated the development and deployment of large-scale distributed applications. The middleware for orchestrating applications that consist of several distributed services has to be inherently distributed as well, in order to provide a high degree of scalability and to avoid any single point of failure. Self-healing execution of composite services requires replicated control metadata and instance data in a way that does not affect adaptivity and elasticity of the middleware. In this paper, we present OSIRIS-SR, a decentralized approach to self-healing composite service execution in a distributed environment. OSIRIS-SR exploits dedicated node monitors, organized in a self-organizing Safety Ring, for the replication of control data. Moreover, OSIRIS-SR leverages virtual stable storage for managing composite service instance data in a robust way. We present the architecture of OSIRIS-SR's Safety Ring and discuss how it provides self-healing composite service execution. The performance evaluation shows that the additional gain in robustness has only marginal effects on the scalability characteristics of the system.