Application portals: practice and experience

The implementation of multiple Grid computing portals has led us to develop a methodology for Grid portal development that facilitates rapid prototyping and building of portals. Based on the NPACI Grid Portal Toolkit (GridPort) and the NPACI HotPage, all portals inherit interactive Grid services, share a single account and login environment, and share the infrastructure required to support and provide services used by each portal. We have demonstrated that the GridPort software can be used in production application portal environments, that the software can be configured to extend multiple sites. In this paper, we describe our experiences gained in building Grid portals and developing software for the Grid. We describe the architecture and design of the portal system, Grid services and systems employed, as well as the unique features of the system. We present descriptions of several application portals and the driving design choices. Finally, we discuss the new and emerging architecture system that being studied based on the web services architecture. 1. Overview Computational science portals provide the scientific community with familiar and simplified interfaces to high-performance compute resources. The Grid [1] is a term that is applied to the infrastructure being constructed to interconnect these highly distributed compute, archival, instrumentation, and other resources into a large, parallel, computational resource [2]. Based on our experiences implementing user portals such as the PACI and NPACI HotPages [3], and application portals including the GAMESS, Pharmacokinetic Modeling (LAPK), Protein Database Combinatorial Extension (PDB/CE), and Telescience portals [4,5,6,7], we have found that a non-trivial level of effort is required to set up a Grid portal. Additionally, we find that a significant level of effort is required in order to establish inter-organizational resource sharing, often required when implementing community models. Our solution for building these portals has been to develop toolkits such as the Grid Portal Toolkit (GridPort) [8,9] and the Perl Commodity Grid (CoG) Toolkit [10,11]. To simplify and generalize the task of building and hosting multiple portals, we have developed a unique methodology that has evolved into an integrated, layered portal “services” approach. GridPort is designed so that multiple application portals share the same installation of GridPort, and inherit connectivity to the computational Grid that includes interactive services, data, file, and account management, and share a single accounting and login environment. We have demonstrated that toolkits such as GridPort can be used in production application portal environments, that the software can be configured to extend to resources beyond NPACI and SDSC (Alliance, PSC, and NASA/IPG), and that it is easily ported to other centers and systems. Additionally, we have shown that GridPort software can be extended to support the web-services architecture [12] that is being developed for commercial purposes and is being explored by the Grid Computing Environments research area of the Global Grid Forum [13,14]. In this paper, we describe our experiences gained in building Grid portals and developing software for the Grid. First, we take some time to the project background and how the project has evolved to the present state. Next, we describe the architecture and design of the portal system and what Grid services and systems are currently employed as well as what features are supported by the software. This discussion is followed by a discussion of a variety of application portals and the driving design choices, which demonstrates the usefulness of this software system by examining GridPort-based production portals. Finally, we discuss the new and emerging architecture system that being studied based on the web services architecture.