Bridging Two Grids: The SAM-grid/LCG Integration Project

SAM-Grid is an integrated data, job, and information management system. SAM-Grid addresses the distributed computing needs of the Dzero experiment at Fermi National Accelerator Laboratory, Batavia, IL. The system typically relies on SAM-Grid specific services deployed at the remote sites in order to manage the computing and storage resources. Such deployment requires special agreements with each resource provider, and it is a labor intensive process. Some members of the Dzero VO also have access to computing resources through the Large Hydron Collider Computing Grid (LCG) infrastructure. Therefore, Dzero users can enter into resource sharing agreements and deployment of standard middleware within the framework of the LCG project. The SAM-Grid/LCG interoperability project was started to enable the Dzero users to access the LCG pool of resources while, retain the user-friendliness of the SAM-Grid interface. This "bridging" between grids is beneficial for both SAM-Grid and LCG, as it minimizes the deployment efforts of the SAM-Grid team and tests the LCG computing infrastructure with data intensive production applications of a running high energy physics experiment, which, are also the types of applications that LCG will have to run once LHC goes into production. The interoperability system is centered on "forwarding" nodes, which receive jobs prepared by the SAM-Grid interface and submits them to LCG. In this thesis, we discuss the architecture of the forwarding system and how it addresses issues of service accessibility, scalability, security challenges, operational and support challenges, which arise when operating this system in production.