Towards Dynamic Reconfiguration of Distributed Publish-Subscribe Systems

Publish-subscribe middleware allows the components of a distributed application to subscribe for event notifications and provides the infrastructure enabling event routing from sources to subscribers. This model decouples publishers from subscribers, and in principle makes it amenable to highly dynamic environments. Nevertheless, publish-subscribe systems exploiting a distributed event dispatcher are typically not able to rearrange dynamically their operations to adapt to changes impacting the topology of the dispatching infrastructure. In this work, we first describe two solutions available in the literature that constitute the extremes of the reconfiguration spectrum in terms of the number of nodes potentially affected by the reconfiguration. They differ essentially in the tradeoffs between simplicity and efficiency. Then, we introduce our contribution as a new algorithm that strikes a balance between the aforementioned solutions by tolerating frequent reconfigurations at the cost of moderate overhead.