Building Grid Services for User Portals

A Grid portal is a user’s point of access to a Grid system [3,5,6,9]. It provides an environment where the user can access Grid resources and services, execute and monitor Grid applications, and collaborate with other users. A number of Grid portals exist or are currently under construction including the NEESgrid Portal [14], the Alliance Portal [22], the GENIUS Portal for the European Data Grid [19], and the IeSE (Integrated eScience Environment) [20]. Also, several large collaborative efforts are underway to build portal construction toolkits based on OGSA Grid services, including the GridSphere project [23] in Germany and the NSF NMI Open Grid Computing Environment project in the US. Over the past nine months these projects have evolved a standard style for interacting with Grid and Web services as back-ends to the portal. The architecture that has developed is based on the idea that the portal server is a container for “user facing” Grid service clients which are designed according to the portlet model. A portlet is a server component that controls a small, userconfigured window in a “pane” on the user’s web browser. There is now a standard specification for portlets [21] and the portlet model is supported by most of the major vendors of portal software. It is also a standard supported by the Apache open source software foundation.