背景：
kubeadm安装的k8s集群，怎么查看etcd集群的状态，判断是否OK呢？
方法：
执行以下命令，查看输出

etcdurl=`docker exec etcd ps -o args |grep -v ps |grep -v COMMAND |awk '{print $7}'`
docker exec etcd etcdctl --endpoints ${etcdurl} cluster-health 

如果输出 cluster is healthy表示集群健康，否则，集群状态有问题

[root@master01 ~]# docker exec etcd etcdctl --endpoints ${etcdurl} cluster-health 
member bd808d0fa461a88 is healthy: got healthy result from http://192.168.100.46:2379
member e240d98762f39bc is healthy: got healthy result from http://192.168.100.45:2379
member 630f756482048e6d is healthy: got healthy result from http://192.168.100.47:2379
cluster is healthy
[root@master01 ~]# 

备注：
二进制安装的集群 docker 相关命令替换成二进制 执行文件名即可。