Decentralized performance-aware reconfiguration of complex service configurations

Execution of complex workflows is one of many applications of Peer-to-Peer (P2P) networks. Sustaining complex workflows in a dynamic P2P network requires adaptation when hosts involved in the workflow lose network connectivity. Adaptation of complex workflows without centralised monitoring and control is a challenge, and is often limited to instance replacement. If requirements are given on the performance of the complex workflow as a whole, then possibilities for automated adaptation are limited even more. This paper [1] describes how adaptation of complex web service configurations can be applied on complex workflows in P2P networks. The paper describes the structures needed for automated reconfiguration of service compositions, and how performance awareness can be created. The structures described are: web services, templates, and configurations. For each structure, the relation to the nodes on the P2P network is explained. In Figure 1 a template-based configuration is displayed, where templates and web services are used to define a layered configuration. The template definitions contains propagation functions, to determine properties of the overall configuration, and inverse propagation functions to disseminate requirements, posed on the overall configurations, to the individual web services and templates.