安装kubenetes https://kubernetes.io/docs/setup/independent/install-kubeadm/ 

• kubeadm: the command to bootstrap the cluster.启动集群命令

• kubelet: the component that runs on all of the machines in your cluster and does things like starting pods and containers.运行于集群上的所有机器，用来启动pod和容器

• kubectl: the command line util to talk to your cluster. 命令行执行某些命令

The master is the machine where the control plane components run, including etcd (the cluster database) and the API server (which the kubectl CLI communicates with).主机是控制组件运行的地方，包括了etcd集群数据库和api server（kubectl命令行与之进行通信）