参考资料：
How to get started, and achieve tasks, using Kubernetes：http://kubernetes.io/docs/getting-started-guides/ubuntu/
How to get started, and achieve tasks, using Kubernetes：http://kubernetes.io/docs/user-guide/connecting-applications/
User FAQ：https://github.com/kubernetes/kubernetes/wiki/User-FAQ#how-do-i-change-the-size-of-my-cluster/
kubernetes/cluster/ubuntu/download-release.sh：https://github.com/kubernetes/kubernetes/blob/master/cluster/ubuntu/download-release.sh