《Accurate_proactive_adaptation_of_SOA》.pdf

Accurate Proactive Adaptation of Service-Oriented Systems Andreas Metzger, Osama Sammodi, and Klaus Pohl Paluno (The Ruhr Institute for Software Technology) University of Duisburg-Essen, Essen, Germany {andreas.metzger,osama.sammodi,klaus.pohl}@paluno.uni-due.de Abstract. As service-oriented systems are increasingly composed of third-party services accessible over the Internet, self-adaptation capabil- ities promise to make these systems become robust and resilient against third-party service failures that may negatively impact on system qual- ity. In such a setting, proactive adaptation capabilities will provide sig- nificant benefits by predicting pending service failures and mitigating their negative impact on system quality. Proactive adaptation requires accurate quality prediction techniques; firstly, because executing unnec- essary proactive adaptations (due to false positive predictions) might lead to additional costs or follow-up-failures; secondly, because proactive adaptation opportunities may be missed (due to false negative predic- tions). This book chapter reviews solutions for measuring and ensuring the accuracy of online service quality predictions. It critically analyses their applicability in the setting of third-party services and supports this analysis with empirical data. Keywords: Service-oriented computing, software services, accuracy, metrics, online quality prediction, online failure prediction. 1 Motivation Service-orientation is increasingly adopted as a paradigm for building highly dy- namic, distributed software systems. Those service-oriented systems are built by composing and integ