A Layered Virtual Organization Architecture for Grid

Virtual organizations (VO) are widely accepted in the grid and other distributed computing environments. However, there are few effective VO implementations. This paper presents a layered architecture to construct Agora, an implementation of VO. Agora manages users, resources, and agora instances, provides policies to support a DAC/MAC-hybrid cross-domain access control mechanism, and maintains the context of operations. The Agora architecture consists of three layers. At the bottom is the physical layer containing external resources, then an abstraction RController is introduced to manipulate external resources. Above the physical layer, all the involved entities, including users, resources, and agoras, are abstracted as GNodes, and a naming layer is introduced to manage these GNodes. At the top, the logic layer implements all the Agora functionalities. This architecture has been implemented in Vega GOS and applied in the China National Grid and other grid platforms. The evaluation shows that the architecture provides minimal but sufficient VO functionalities while keeping decentralization, flexibility, simplicity, and effectiveness.