An Approach for Harmonizing Conflicting Policies in Multiple Self-Adaptive Modules

A recent approach to monitor and adapt system behavior at runtime is to decouple one or more external modules and self-adaptive mechanism from the target system. An important challenge arises when more than one such self-adaptive module is employed: how can we ensure that they cooperate without conflicts in a coherent fashion? This paper describes our initial approach for harmonizing conflicting policies in the presence of multiple self-adaptive modules. The main distribution of the paper is to resolve conflicts using an extended ECA rule paradigm to coordinate self-adaptive actions among multiple external modules. The approach shares advantages with other policy languages, i.e., the declarative and domain-independent semantics of policy rules. However, a key benefit of our approach is that both conflicting actions and influence of actions are considered. We focus on the problem of harmonizing self-adaptation capability by detecting and further resolving policy conflicts using action-level meta rule and value-level meta rule. Finally, this paper illustrates the efficiency of the approach in a VOD system as a case study, and discusses our future plans.