Gossip-based service coordination for scalability and resilience

Many interesting emerging applications involve the coordination of a large number of service instances, for instance, as targets for dissemination or sources in information gathering. These applications raise hard architectural, scalability, and resilience issues that are not suitably addressed by centralized or monolithic coordination solutions. In this paper we propose a lightweight approach to service coordination aimed at such application scenarios. It is based on gossiping and thus potentially fully decentralized, requiring that each participant is concerned only with a small number of peers. Although being obviously simple and scalable, it has been shown that gossip-based protocols lead to emergent strong resilience guarantees. We illustrate the approach with WS--PushGossip, a proof-of-concept coordination protocol based upon the WS--Coordination framework. Besides presenting WS--PushGossip, we illustrate its usefulness with a sample application, and outline a middleware implementation based on Apache Axis2.(undefined