Future mobile networks (5G) would be much more flexible, dynamic and faster adaptable to match the evolved demand. Network Function Virtualization (NFV) is investigated to take the advantage of information technology (IT) virtualization on telecom networks by separating network functions to be virtualized from underlying dedicated hardwares. Container-based micro-service is currently discussed as being lightweight virtualization approach enabling flexibility and scalability of future mobile networks. Virtualizing mobile network functions, the Serving Gateway (SGW) is analyzed as being the most sensible component, a bottleneck. The containerization seems to be the adequate approach to overcome this issue as it could enable rapid deployment by scaling SGW instances based on workload. In this paper, we discuss the cloudification of mobile network functions using containerization technology and 12 factors principles for enabling such cloudification. An implementation is made using Docker containerization while we employ Docker Swarm for cluster management and deployment. We also build an orchestration testbed for testing the scalability of SGW. This is realized by comparing the performances of two open-source orchestrators: Kubernetes and Mesos- Marathon. The proof of concepts shows clearly that a container-based approach is a viable option for achieving elasticity of future mobile networks.