Decentralized resource brokering for heterogeneous grid environments

Sammanfattning: The emergence of Grid computing infrastructures enables researchers to share resources and collaborate in more efficient ways than before, despite belonging to different organizations and being distanced geographically. While the Grid computing paradigm offers new opportunities, it also gives rise to new difficulties. One such problem is the selection of resources for user applications. Given the large and disparate set of Grid resources, manual resource selection becomes impractical, even for experienced users. This thesis investigates methods, algorithms and software for a Grid resource broker, i.e., a scheduling agent that automates the resource selection process for the user. The development of such a component is a non-trivial task as Grid resources are heterogeneous in hardware, software, availability, ownership and usage policies. A wide range of algorithmically difficult issues must also be solved, including characterization of jobs, prediction of resource performance, data placement considerations, and, how to provide Quality of Service guarantees. One contribution of this thesis is the development of resource brokering algorithms that enable resource selection based on Grid job performance predictions and use advance reservations to provide Quality of Service guarantees. The thesis also includes an algorithm for coallocation of sets of jobs. This algorithm guarantees a simultaneous start of each subjob, as required e.g., when running larger-than-supercomputer simulations that involve multiple resources.We today have the somewhat paradoxal situation where Grids, originally aimed to overcome interoperability problems between different computing platforms, themselves struggle with interoperability problems caused by the wide range of interfaces, protocols and data formats that are used in different environments. The reasons for this situation are obvious, expected and almost impossible to avoid, as the task of defining appropriate standards, models and best-practices must be preceded by basic research, proof-of-concept implementations and real-world testing. We address the interoperability problem with a generic Grid resource brokering architecture and job submission service.By using (proposed) standard formats and protocols, the service acts as an interoperability-bridge that translates job requests between clients and resources running different Grid middlewares. This concept is demonstrated by the integration of the service with three different Grid middlewares. The service also enables users to both fine-tune the existing resource selection algorithms and plug in custom brokering algorithms tailored to their requirements.