Modeling and Analyzing Dynamic Fault-Tolerant Strategy for Deadline Constrained Task Scheduling in Cloud Computing

Cloud computing has been increasingly concerned in scientific computing area. More and more enterprises and research institutes have migrated their applications to the clouds. Due to the complexity of cloud computing system in structural and behavioral aspects, how to design the fault tolerant cloud computing system becomes a challenging problem. This paper investigates the modeling and analysis of fault tolerant strategy for deadline constrained task scheduling in cloud computing. First, a formal description language is defined to accurately model the different components of cloud application, and use it to characterize the operational mechanisms and fault behaviors. Second, we propose a fault tolerant strategy, which includes the scheduling mechanism, synchronization mechanism, and exception mechanism, to dynamically compute the execution mode and required virtual machine for tasks, thus ensuring the reliability and real-time requirement of cloud application. An enforcement algorithm is also designed to realize the proposed strategy. Third, the techniques of Petri nets are provided to analyze and validate the correctness of proposed method. Finally, several experiments are done to illustrate that the reliability of cloud application is improved and its deadline is met.