Cloud services have been widely deployed on Iarge-scale datacenters by Cloud Service Providers (CSPs) to provide users with better performance and reliability. However, interactions between datacenter selection and multiple traffic engineering (TE) of many physical networks operated by Internet Service Providers (ISPs) may occur, which may lead to performance loss. In this paper, we propose a cooperative approach based on Nash's bargaining solution (NBS) for CSP and ISPs to improve their performance, which considers both Pareto optimality and fairness. Then, in order to facilitate the actual deployment, we also design a decomposition algorithm to calculate the NBS. Simulations are performed to verify our analysis on different network environments.