WS Information Services: Key Concepts

Overview
>Uses and Benefits of the Index Service
Information Model
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Uses/Benefits of the Index Service

The Index Service provides the following key capabilities:

  • An interface for connecting external Service Data Provider programs to service instances

The Index Service provides a standard mechanism for dynamic generation of service data via external programs.  These external provider programs can be the core providers that are part of GT3.2 or user-created, custom providers.

  • A generic framework for aggregation of service data

Service Data, which can be generated from multiple Service Data Provider programs and/or contained in messages delivered from other Grid services, can be indexed in different ways in order to provide different aggregate data views.  Various command-line tools and GUIs can be used as clients to the aggregate data views.  The Index Service uses standard OGSA notification mechanisms for subscription and notification of Service Data.

  • A Registry of Grid services

A set of available Grid services is maintained in a Registry.  A Registry allows for soft-state registration of Grid services, in that a set of services can be registered and periodically updated as required.  The Index Service registry can be used to support lifetime, query, service data aggregation, or other operations on a given member service.  A Registry is also known as a Service Group.

  • A dynamic data-generating and indexing node, suitable for use in a hierarchy or federation of services

The Index Service combines ServiceDataProviderExecution components with  DataAggregation and ServiceGroup components to create a dynamic data-generating and indexing node, similar in concept to an MDS2 hierarchical GIIS.  Index Services can be combined in a variety of topologies, useful in building Virtual Organizations.