A modelling approach to Service oriented Architecture for on-line diagnosis

Abstract

Failure diagnosis is one of the key challenges of Service oriented Architectures. One of the methods of identifying occurrences of failure is to use Diagnosers; software modules or services are deployed with the system to monitor the interaction between services for identifying whether a failure has happened or may have happened. This paper aims to present a suitable modelling framework to allow automated creation of Diagnosers based on Discrete Event System (DES) theory. Coming up with an appropriate modelling language framework is a prerequisite to applying DES techniques. Modelling languages popular in DES, such as Petri nets and automata, despite being sufficiently adequate for modelling, are not well adopted by the SoA community. Inspired by Petri nets and Workflow Graph, the modelling suggested in this paper closely follows BPEL that is widely used by the community. In particular, our language includes constructs that are supported by major tool vendors. To demonstrate that the suggested formal language is a suitable basis for the application of DES theory, we have extended one of the existing DES methods for the creation of centralised Diagnoser. Two algorithms for creating Diagnosers are put forward. These algorithms are applied into the models that are abstracted from the BPEL representation of the involving services. As a proof of concept, an implementation of the suggested approach is created as an Oracle JDeveloper plugin that automatically produces new Diagnosing services and integrates them to work with existing services. The paper ends with a series of empirical results on the performance-related aspects of the proposed method.