A Framework for Meta-Scheduling WSRF-based Services

The maturity and stability of WSRF and its related technologies is producing a new demand for meta-scheduling WSRF-based services. In fact, many scientific institutions and universities are looking into the possibility of using WSRF-based services as production-level services. For this purpose, they need a meta-scheduling solution that selects one of the WSRF-based services, each of which is deployed in an organization for fault tolerance and load balancing. However, methods for meta-scheduling services among multiple sites have not been discussed well. This paper describes a new framework (MSSA: Meta-Scheduling Service Architecture) for scheduling and selecting WSRF-based services deployed over multiple sites. This framework provides a transparent scheduling method to users. Our method takes advantage of the factory pattern used typical WSRF services. The framework builds scheduling processes into the factory pattern and hides the complexity of the scheduling process from users. MSSA defines a meta-factory service that selects a suitable factory service and delegates the user´s request to the factory service. By using this meta-factory service instead of using the original factory services, users can utilize meta-scheduling features transparently. MSSA can build hierarchical structures of meta-factory services to construct scalable scheduling environment, and can also switch scheduling policies easily. In this paper, the design and implementation of MSSA is discussed.