Resource-Aware Deployment and Configuration of QoS-Enabled Middleware

Ad hoc Deployment and Configuration (D&C) of fault-tolerance mechanisms can lead to unacceptable response times, overloads, and low-availability for soft real-time applications. This paper describes how the Quality-of-Service (QoS)-enabled middleware called DeCoRAM (Deployment and Configuration Reasoning via Analysis and Modeling) provides a holistic and automated solution to fault-tolerance and real-time D&C through two novel capabilities. First, DeCoRAM provides a deployment-time allocation and scheduling algorithm that maps passively replicated application components to appropriate hosts subject to their soft real-time requirements and determines the failover order of application replicas based on their worst case state synchronization delays. Second, DeCoRAM's model-driven D&C engine deploys and configures replicas for each application and provides resource-aware failover and delay-bounded state synchronization between backup and primary replicas.