A fault tolerant object management framework based on middleware for dynamic reconfiguration

An important emerging requirement for distributed systems is adaptive QoS, which necessitates more flexible system infrastructure components that can adapt robustly to dynamic end-to-end changes in application requirements and environmental conditions. This paper shows how to add a characteristic of dynamic configuration, from the perspective of fault tolerance QoS, to the fault tolerant object management framework based on middleware. Three specific technical challenges in satisfying the requirements are: 1) perceive the changes of environment; 2) define the trigger for reconfiguration; 3) reconfigure the resources if the trigger satisfied. We define dynamic reconfiguration as the relation among fault tolerance properties, description of computing environment changes and dynamic adjustment algorithm, Based on this definition the management framework for dynamic reconfiguration is built. In which, the introduction of reflection model and publish/subscribe model makes the acquirement and notification of information more convenient and flexible, and the adoption of policy customization mechanism makes reconfiguration enforced more effectively. The framework presented in this paper has been validated in a prototype. ? 2005 World Scientific Publishing Co. Pte. Ltd.EI