Towards an Agile Computing Approach to Dynamic and Adaptive Service-Oriented Architectures

Agile computing is an innovative metaphor for distributed computing systems and prescribes a new approach to their design and implementation. Agile computing may be defined as opportunistically discovering, manipulating, and exploiting available computing and communication resources in order to improve capability, performance, efficiency, faulttolerance, and survivability. This paper describes the realization of the middleware and the AgServe library that supports dynamic and adaptive serviceoriented architectures. The middleware supports service definition, instantiation, invocation, relocation, and termination to be performed dynamically at runtime. A coordination mechanism continuously monitors service resource utilization, invocation patterns, and network and node resource availability to determine optimal locations for services to be instantiated and invoked. The continuously adaptive nature of agile computing makes it well suited to providing a foundation for autonomic computing.