Cloud computing has been empowered with the introduction of Software-Defined Networking (SDN) which enabled dynamic controllability of cloud network infrastructure. Despite the increasing popularity of studies for joint resource optimization in the cloud environment with SDN technology, the realization is still limited for developing integrated management platform providing a simultaneous controllability of computing and networking infrastructures. In this paper, we propose SDCon, a practical platform developed on OpenStack and OpenDaylight to provide integrated manageability for both resources in cloud infrastructure. The platform can perform VM placement and migration, network flow scheduling and bandwidth allocation, real-time monitoring of computing and networking resources, and measuring power usage of the infrastructure with a single platform. We also propose a network topology aware VM placement algorithm for heterogeneous resource configuration (TOPO-Het) that consolidates the connected VMs into closely connected compute nodes to reduce the overall network traffic. The proposed algorithm is evaluated on SDCon and compared with the results from the state-of-the-art baselines. Results of the empirical evaluation with Wikipedia application show that the proposed algorithm can effectively improve the response time while reducing the total network traffic. It also shows the effectiveness of SDCon to manage both resources simultaneously.