Service Assignment in Federated Cloud Environments Based on Multi-objective Optimization of Security

Cloud federation allows interconnected Cloud Computing environments of different Cloud Service Providers (CSPs) to share their resources and deliver more efficient service performance. However, each CSP provides a different level of security in terms of cost and performance. Instead of consuming the whole set of Cloud services that are required to deploy an application through a single CSP, consumers could benefit from the Cloud federation and flexibly assign the services to multiple CSPs in order to satisfy all their services' security requirements. In this paper, we model the service assignment problem in federated Cloud environments as a Multi-objective optimization problem based on security. The model allows consumers to consider a trade-off between three security factors: cost, performance, and risk, when assigning their services to CSPs. The cost and performance of the delivered security services are evaluated using a set of quantitative metrics which we propose. We then solve the problem using the preemptive optimization method which permits to take into consideration the customer's priorities. Simulations showed that the model helps in reducing the rate of security and performance violations.