Variability modelling and service- orientation are important approaches for achieving both the flexibility and adaptability required by stakeholders of software systems. In this paper we present an approach that integrates domain models captured in the i* modelling framework with variability models to support runtime monitoring and adaptation of service-oriented systems. We believe that approaches integrating goal-oriented modelling and variability management are needed to build, operate, and evolve such systems. We illustrate our approach using two scenarios and present a tentative tool architecture based on an existing product line engineering tool suite.