Research On Meta-Service Supporting OGSA

Grid is a rapidly-developing researching area, and OGSA is currently the newest and most important grid structure form. Service Description, Service Registration, Service Discovery and Service Management are the core to implement OGSA. Meta-service module supports these core modules, is the basis of them, which is directly related with the realization of grid idiosyncrasies such as variety dynamicism width and isomerity and with optimizing resources & services sharing in OGSA.Classifying resources & services is the premise of describing them. Rational classification can optimize the management of resources & services, and improve grid performance. Meta-service information is the abstract description of resources & services in grid environment, which combines Web Service technology, and adopts idea of service-orientation and object-orientation. The abstract description provides organization and management of resources & services one uniform mapping. The attributes of encapsulated meta-service information are vital parameters for implementing organization and management of resources & services. Meta-service module also takes dynamicism of attributes into account.The supporting of meta-service module in the aspects of discovery promulgation and registration of resources & services is discussed. A Grid structure——4-layer virtual machine model and description of corresponding algorithms to realize the model are introduced. The layer of meta-service information servers net is the platform for applications and resources & services to interoperate on. Its handled objects are meta-service information, and it can adopt many organization and management tactics (for instance, LAN-orientation, resources & services-orientation, VO-orientation) to provide application layer uniform mapping. Meta-service information servers see to meta-service information structure which corresponds different tactics, and solve lots of problems, such as the creation and maintenance of meta-service information servers net, tactics of updating and clustering meta-service information, and tactics of disposing requests of resources & services. Meta-service module also supports organizing and managing meta-service information. Nicer organization and management can more convenience realization of Service Registration, Service Discovery, Service Promulgation. On basis of actual points of grid environment, meta-service module introduces a service information model—logic service information tree which can fit the dynamicism and isomerity of grid service much better. A form of computing ability logic service information tree is also drawn as an instance. This model realizes managing entities and abstract description separately, assimilates idea of resource-pool, and uses tree hiberarchy, which makes meta-service information more consecuted and more easily to realize the registration location and management of services. This model has commonability, and can be used to describe grid services widely and to abstract lots of grid services to be service object instances which have the basal attribute of service object sets. Because this model describes grid services specifically, it can exhibit the dymanicism much better, and support dynamic load balance in OGSA expediently, which can optimize performance of grid more, and improve utilization ratio of grid resources.The organization and management of VO meta-service engenders VO logic level information tree by virtue of idea of logic service information tree, which impersonally factually reflects VO's structure, and realizes the organization and management of VO's meta-service information. For the width of grid services, meta-service module adopts distribution-centralization redundancy technology to organize the meta-service information servers in grid. NHPCGE(national high performance computing grid environment)can introduce the tactic to model the meta-service information management, which optimizes and extend HPC Grid in some way and has stronger fault-tolerant quality and stalwart quality.