Workflows are adopted as a powerful modeling technique to represent diverse applications in different scientific fields as a number of loosely coupled tasks. Given the unique features of cloud technology, the issue of cloud workflow scheduling is a critical research topic. Users can utilize services on the cloud in a pay-as-you-go manner and meet their quality of service (QoS) requirements. In the context of the commercial cloud, execution time and especially execution expenses are considered as two of the most important QoS requirements. On the other hand, the remarkable growth of multicore processor technology has led to the use of these processors by Infrastructure as a Service cloud service providers. Therefore, considering the multicore processing resources on the cloud, in addition to time and cost constraints, makes cloud workflow scheduling even more challenging. In this research, a heuristic workflow scheduling algorithm is proposed that attempts to minimize the execution cost considering a user-defined deadline constraint. The proposed algorithm divides the workflow into a number of clusters and then an extendable and flexible scoring approach chooses the best cluster combinations to achieve the algorithm’s goals. Experimental results demonstrate a great reduction in resource leasing costs while the workflow deadline is met.

Keywords