A Trust Service-Oriented Scheduling Model for Workflow Applications in Cloud Computing

Cloud services have been utilized in large-scale distributed environments. As an effective service aggregation methodology, workflow technology has been used to construct composite services. Efficient and dependable workflow scheduling (WFS) is crucial for integrating enterprise systems. While WFS has been widely studied, WFS-related algorithms are mainly focused on optimizing execution time or cost. However, in cloud computing environment, WFS is up against the threats of the inherent uncertainty and unreliability to the applications. Therefore, trust service-oriented strategies must be considered in WFS. As a result, this paper proposes a trust service-oriented workflow scheduling algorithm. The scheduling algorithm adopts a trust metric that combines direct trust and recommendation trust. In addition, we provide balance policies to enable users to balance different requirements, including time, cost, and trust. A case study was conducted to illustrate the value of the proposed algorithm. The experimental results show that the proposed approach is effective and feasible.