EMI Registry Design

Grid services are the fundamental building blocks of today's Distributed Computing Infrastructures (DCI). The discovery of services in the DCI is a primary function that is a precursor to other tasks such as workload and data management. In this context, a service registry can be used to fulfil such a requirement. Existing service registries, such as the ARC Information Index or UNICORE Registry, are examples that have proven themselves in production environments. Such implementations provide a centralized service registry, however, todays DCIs, such as EGI, are based on a federation model. It is therefore necessary for the service registry to mirror such a model in order for it to seamlessly fit into the operational and management requirements - a DCI built using federated approach. This document presents an architecture for a federated service registry and a prototype based on this architecture, the EMI Registry. Special attention is given to how the federated service registry is robust to environment failures, which are frequent in distributed environments.