Cloud VM Provisioning Using Analytical Performance Models

When an application deployed in the cloud faces changing workload, the services of the application need scaling up or down in response. The services run on Virtual Machines (VM) or container instances. Application Providers (APs) decide on how the applications are scaled through VM provisioning and through the placement of the services on those VMs. Various drivers guide this decision making. Application performance and cost are two such drivers. In this paper, we answer the question of how APs can meet the performance constraints of their applications while minimizing the cost of the running VMs. A VM provisioning problem is formulated which expects to meet mean response time constraints and minimize the cost, where VM-types having different cost rates are used. The proposed solution is based on genetic algorithm and bottleneck strength value. For the case study, a decision maker is implemented for a web application. The proposed solution is compared against an exhaustive search, a simple genetic algorithm and a random search. It is shown that our solution is able meet response time constraints with near optimal minimization of cost. The solution also results in better cost than random search and the plain genetic algorithm solution at the expense of slightly longer runtime.