Resource Allocation and Scheduling of Linear Workflow Applications with Ageing Priorities and Transient Failures

In distributed environments, applications are usually complex and computationally demanding, having a linear workflow (LW) structure. Additionally, such LW jobs may also have different priorities for processing. This entails the danger of long delays for low priority jobs. Furthermore, transient software failures may occur during the execution of the workload. Consequently, resource allocation, scheduling and fault tolerance are three crucial aspects that should be efficiently and effectively addressed in such environments, in order to achieve good system performance. To this end, in this paper we investigate the resource allocation and scheduling of LW jobs that arrive dynamically in an environment of distributed resources. We consider that the LW jobs have different priorities and that transient software failures may occur during their execution. A novel scheduling technique is proposed, which takes into account the ageing priorities of the LW jobs, as well as the resulting scheduling overhead. We examine the performance of three routing strategies in this framework, under various load cases and different failure probabilities, taking also into account their implementation complexity. The simulation results reveal how each routing strategy is affected in each of the examined scenarios.