Propagation-aware Temporal Verification for Parallel Business Cloud Workflows

Massive parallel business workflows running in the cloud are prone to temporal violations (namely intermediate runtime delays) due to various reasons such as service performance fluctuation and resource conflicts. To deliver satisfactory on-time completion, cloud workflow temporal verification is employed to accurately detect time delays of workflow activities and timely handle temporal violations before final deadline is violated. While most of the existing works only monitor the time delays of individual workflow activities or workflow instances, the effect of time delay propagation (similar to "Butterfly Effect") in cloud workflow systems has been overlooked, which has significant impact on the accuracy of temporal verification. In this paper, we present a propagation-aware temporal verification strategy for parallel business cloud workflows. Specifically, we first analyze the effect of time delay propagation in cloud workflow systems. Then, we present the novel temporal verification strategy based on a new propagation-aware throughput consistency model which includes the propagation effect. Experimental results demonstrate that compared with the traditional strategy, our propagation-aware strategy has higher success rate in achieving target on-time completion rate for massive parallel business cloud workflows.