Autonomic computing control of composed web services

Abstract

Software as a service (SaaS) can be delivered by composing software applications using web services hosted in one or more administrative domains. In this context, web service composition has a considerable impact on the delivered service affecting its quality (QoS). There is therefore a need to keep the service QoS parameters under control when the service is delivered by a combination of different web services. This paper investigates the composition of web services, and its implications on the overall QoS guarantees as represented by the service response times, when autonomic computing control mechanisms are in place. A control based approach of the autonomic computing concept is used to investigate the dynamic composition of web services when the service is provided by a set of web services linked via cooperation protocols that define a global process choreography. Web services are modeled as scheduled computational processes waiting in a queue to cooperate in delivering the service. The paper proposes an input-state-output mathematical model for web services and further investigates, in this context, their composition hypothesis, principles, and rules.