A QoS‐aware exception handling method in scientific workflow execution

Scientific workflow is gaining ever‐increasing attention as it integrates a wide range of heterogeneous services to enable and accelerate the scientific discovery processes. However, the exception occurred in a scientific workflow execution often decreases the robustness of a scientific workflow system. For example, if a service engaged in a scientific workflow schedule becomes unavailable during its execution, an exception might be raised and the whole workflow execution may be interrupted unexpectedly. In this situation, it is a challenge to smooth the interrupted workflow execution. In view of this challenge, an exception handling method, named RelaxingMe (constraints Relaxing Method, RelaxingMe ) is proposed in this paper. This method aims at relaxing the original QoS constraint values requested by the interrupted task node, in order to find a near‐to‐optimal candidate service to replace the unavailable one. At last, the feasibility of our method is evaluated by an experiment. Copyright © 2011 John Wiley & Sons, Ltd.