1、etcd没有启动的
[root@mcwk8s03 ~]# kubectl get nodes
Unable to connect to the server: context deadline exceeded
启动之后就可以使用了
[root@mcwk8s03 ~]# kubectl get nodes
NAME STATUS ROLES AGE VERSION
mcwk8s05 NotReady <none> 404d v1.15.12
mcwk8s06 NotReady <none> 404d v1.15.12
[root@mcwk8s03 ~]#