Job And Resource Description Language In Computational Grid Environment

This paper is part of project "Dynamic Selecting Resources and Rescheduling Tasks on Computing Grids"which is provided by Fund for Jilin Distinguished Young Scholars. In distributed and heterogeneous grid environment, resources maybe crash or draw back by their owners, which is hard for settling large scale problems. It is necessary to migrate applications to other available resources and keep them running until accomplishment. The purpose of the project is to solve such problems by selecting appropriate resources and rescheduling tasks. Allowing for communication overhead, it presents and realizes a scheduling and rescheduling model and algorithms for parallel application based on fault tolerance and load balancing. Because resources in grid belong to different organizations and owners, usage policies of these resources are also various. For example, it maybe rule that if you want to run your task on the node, its owner must belong to a specific group, or you must execute jobs in given time. So it is rather difficult to discover and select resources. How to coordinate owners with users is a key. It is necessary to provide a kind of description language that can descript requirement, constraint, definition and policy of both owners and users. It is the right premise of the job in this paper. We present a kind of language, CDL (Common Description Language) in this paper. It enables customs to descript their destinations and requirements; what's more it allows owners to display their resources and constraints. The language refers the conception of Condor's ClassAd which use property/value pair to descript resources and jobs. We define specific properties, types, functions and policies, and use ClassAd library to read, parse and convert CDL to specific format strings. Meanwhile, we design user interface (UI) which realizes the CDL and manages jobs preliminary, such as submitting jobs to broker, canceling execution of tasks and outputting the results. Authentication mechanism of Globus to identify the users is used for network security. There are three steps in realization: realization of description language, authentication and proxy, monitoring jobs and output. The first step is the basis of our work. Class ClassAdReader in ClassAd library is responsible for reading input, and change them into string stream which is then analyzed by Parser that is also included in ClassAd library. At...