QoS-based feedback for service compositions

The Service Oriented Architecture is boosting a fast move from developing applications as stand-alone systems, to developing applications as composition of autonomous and heterogeneous services. Service compositions are required to adapt dynamically to changing workloads, scenarios and objectives, and to achieve a certain Quality of Service (QoS). Guaranteeing such requirements is not a trivial task, since run-time variability makes the process of devising service compositions challenging for software designers. In this paper, we exploit the QoS analysis at run time to support software design, highlighting service compositions where QoS predictions are not reliable enough. To this end, we propose a QoS-based feedback framework that makes use of design-time and run-time knowledge to manage QoS data over time, and support software architect while devising a service composition that best fits QoS requirements. We illustrate the feasibility and effectiveness of the approach on a case study from the e-health domain.