Exogenous management in autonomic service compositions

This paper proposes that software architectures that support autonomic service-oriented computing need to have an exogenous management structure. Exogenous management regards autonomicity as a property of relationships between elements, rather than a property of the elements themselves. We explain the concept of exogenous management, and show how a number of desirable attributes that support autonomicity flow from this approach. These attributes include self-management; separability; recursive composition; and grounding through the monitoring of interactions. We will show how these attributes help enhance the adaptability and control the complexity of context-aware compositions of services. We then discuss how this exogenous approach to management has been implemented in the ROAD (Role-oriented Adaptive Design) programming framework. This framework is extended by software developers to create service compositions whose level of autonomicity can be incrementally modified at runtime.