OMII-Europe has selected specific components to work with and make available across the middleware platforms.
These components make use of OGF standards and some of them are already available on some of our chosen platforms. OMII-Europe is making them work across all our chosen platforms. These components are briefly described below.
Basic Execution Service (BES)
A Basic Execution Service (BES) is a service to which clients can send requests to initiate, monitor and manage computational activities (or jobs). The Open Grid Forum (OGF) provides a detailed specification for a BES. This is complemented by the Job Submission Description Language (JSDL) specification. The intention of these specifications is to abstract from the operating system and the cluster controller on which the job is to run. Currently, a mature implementation of these developing specifications is available from the GridSAM project at Imperial College London, or through OMII-UK, who sponsored the development. GridSAM has been shown to work in various environments, in particular with Globus GT2.4 and with the basic Web Services stack available from OMII-UK, and with various schedulers including Condor and PBS. OMII-Europe is deploying a BES on the three platforms and aims to show interoperability between them at the level of jobs being submitted to each without requiring any platform-specific alterations.
Data Integration Service
OGSA-DAI (Open Grid Services Architecture – Data Access and Integration Service) is a middleware component developed at Edinburgh Parallel Computing Centre and currently distributed either standalone or as part of the Globus or OMII-UK distributions. It federates data resources with different support mechanisms (such relational databases, XML databases or flat file systems) allowing uniform access across them. OGSA-DAI allows these data resources to be queried, updated, compressed (and decompressed) and exposed via web services. OMII-Europe is deploying this component on its three platforms and aims to show interoperability between them at the level of data being accessed and updated across them without specialisation of the query.
Virtual Organisation Membership Service
The Virtual Organisation Membership Service (VOMS) manages authorisation information for Virtual Orgnisations (VO). It is essentially a simple account database that holds details of the user’s relationship with her VO: roles, groups and permissions. This service is currently available for use on either gLite or Globus. The OMII-Europe project is making it available on UNICORE and testing it for interoperability across all three platforms.
The Resource Usage Service (RUS) specification from the Open Grid Forum (OGF) is the chosen standard for Accounting Services in Grid solutions. The service is used to track usage so that it can be charged. Since the specification is still in development, candidate components are under review by OMII-Europe. Implementations of early specifications have been made for LCG (parent of gLite) and for GridPP, thus proving the concept. OMII-Europe will validate this component as it becomes available in open source and make it available on the three chosen platforms.
The GridSphere Portal Framework provides an open-source portlet based Web portal. GridSphere enables developers to quickly develop and package third-party portlet web applications that can be run and administered within the GridSphere portlet container. The GridSphere portal framework is open source and available for download along with excellent documentation related to the installation and development of portlets. GridSphere provides a state-of-the-art means for federating computational and data resources across the Web, using Web Services based portlets. OMII-Europe is evaluating GridSphere as an integrating capability across its three platforms, where portlets published via GridSphere will hide details of the platforms from users.
Components from CROWN
OMII-Europe is working with the Chinese project CROWN to source additional components and to test OMII-Europe’s chosen components on the CROWNgrid platform.