A server selection strategy about cloud workflow based on QoS constraint

Cloud computing is an emerging business computing model whose basic idea is to transmit all kinds of resources through the Internet such as storage resources, computing resources, bandwidth and so forth. So users do not need to purchase a large of computing systems to manage their business, on the contrary they only need to purchase the resources according to their needs in order to reduce the cost greatly. Due to the flexibility, convenience and low maintenance cost of cloud computing, more and more service providers choose to deploy their services to the cloud. However, under the influence of uncertain factors such as manufacturing technology, the price and delivery time of virtual machine also been changed. Because of these variations, it is difficult for users to select the appropriate cloud servers at a minimum cost, which will lead to a decline in user experience. To solve the problems above, this paper analyzes the performance of different Ali Cloud servers and proposes a server selection strategy according to the size of the whole instance and the required time of completing the workflow, so as to make the whole workflow instances execution costs as little as possible in the regulations. We also provide experimental results to demonstrate the effectiveness of our selection strategies.