Towards modelling and analysis of a coordination protocol for dynamic software adaptation

Abstract

Software systems are increasingly expected to continue operating at run-time with minimal human interaction. They should consequently be equipped with self-adaptation capabilities in order to adapt themselves in response to changes in their execution conditions. While most of the research in this area focuses on individual parts of an adaptive system, our work leverages on this research but tackles the problem where interdependent and distributed adaptations are concurrently performed. In this paper, we approach behavioural changes of component-based systems in two steps. First, we propose a process to individually adapt one component at a time. Second, we elaborate a coordination protocol to maintain globally consistent state when implementing distributed adaptations. Motivated by the potential benefits of using formalisms, we construct a formal model of our protocol using Coloured Petri Nets in order for an adaptive system to be trusted after adaptation. We verify key behavioural properties and conduct CTL model checking to assess the correctness of the model and thereby the correctness of the protocol.