Research On Dynamic Maintenance For Service-oriented Grid

With the rapid development of grid technology, more and more businesses need toprovide high-quality and nonstop services. However, the recon?guration, resource mainte-nance, and upgrading operations are necessary for those critical businesses. In terms of tra-ditional maintenance technologies, these operations will inevitably cause the decline in thequality of services and service interruptions. When meeting this case in the distributed envi-ronment, a bunch of problems ( including the system heterogeneity, network latency, and soon) make such maintenances and upgrading work dif?cult so as to achieve ef?cient coordi-nation. On the other hand, incorrect maintenance work could lead even to the unavailabilityof the global system. Therefore, how to implement a dynamic maintenance mechanism ina running distributed system or even grid system, which is to maximize the utilization ofgrid resources and demands from users, is the motivation of this paper. Another focus of thepaper is to ?nd out the solutions how to improve the availability of existing grid infrastruc-tures. In addition, from the view of the system architecture, ensuring the accomplishmentof critical applications as soon as possible is also pursed in proposed dynamic maintenancetechnology.First, a highly available dynamic deployment infrastructure (HAND) is proposed in theinfrastructure layer. Six criteria are concluded from the practical experience. Accordingto these criteria, two deployment approaches including Service-level and Container-levelare introduced. The analysis on the correctness and availability for the two approaches ispresented. From the evaluation results of micro benchmark, services scale, and correctness,it proved that HAND can guarantee high availability in dynamic grid infrastructure.Second, the focus moves to the architecture layer. The paper concentrates on how toguarantee the scalability and usability during the scale of physical nodes and the dependen-cies among the grid services are growing to huge. A new architecture named as CobwebGuardian is proposed to resolve this problem. It consists of three executing units in dif-ferent granularity. In addition, it provides three group maintaining algorithms to eliminateor reduce the negative affects from deployment, invocation, and environment dependencies. The interdependent system services in ChinaGrid Support Platform are adopted to evaluatethe ef?ciency. The results proved that the proposed maintenance architecture can bring highthrough puts and availability in runtime.Third, a distributed asynchronous maintaining strategy is proposed upon the proposedinfrastructure and architecture. The motivation is to reduce the affects from grid hetero-geneity and emergent faults during dynamic maintenances. By introducing a three-tierasynchronous model and analyzing the time sequence during the maintenance, the proposedkernel algorithms guarantee that the business logics of upper applications and maintenanceswill not disturb each other. In addition, the ef?ciency and availability are improved much.The asynchronous strategy is implemented in ChinaGrid support platform and a practicalimage processing application is successfully deployed into three heterogenous clusters. Theevaluation results demonstrated that the proposed strategy can improve the ef?ciency andtolerant enough changes of resources and maintaining complexity in homogeneous and het-erogeneous environments.Finally, from the view of application layer, the paper discusses how to ef?cientlycombine the dynamic maintenance with two important technologies (including virtualworkspace service and interoperations) to resolve con?icts from increasing massiveVO users and resourceless problem in grid. Upon ChinaGrid and Grid ProgrammingEnvironment for CGSP(cooperated with Intel corp.), the Globus Toolkit 4.0 developed byU.S. ANL and Unicore 6.0 developed by German D-Grid are adopted as reference. Byusing the integer programming technology, the dynamic maintenance, virtual workspaceservice, and interoperation technologies are orchestrated effectively and ef?ciently. Bythis way, users can ?nish the job requests even when the resources are inadequate in localgrid. The image processing GridBeans are used for evaluations. The results proved that theproposed orchestration model can ef?ciently resolve the problem of resourceless in gridsand guarantee the ef?ciency of jobs execution.