1、防火墙问题，systemctl stop firewalld && systemctl disable firewalld
Aug 16 21:49:11 k01 etcd: health check for peer 1d2b6542084a0b87 could not connect: dial tcp 192.168.1.60:2380: i/o timeout
Aug 16 21:49:11 k01 etcd: health check for peer 1d2b6542084a0b87 could not connect: dial tcp 192.168.1.60:2380: i/o
2、集群节点时钟不一至，使用时钟服务器或者ntpdate time.windows.com。
Aug 16 22:13:46 k01 etcd: the clock difference against peer 1d2b6542084a0b87 is too high [2.304656176s > 1s]
Aug 16 22:14:16 k01 etcd: the clock difference against peer 1d2b6542084a0b87 is too high [2.29437392s > 1s]
Aug 16 22:14:16 k01 etcd: the clock difference against peer 1d2b6542084a0b87 is too high [2.307277917s > 1s]
3、etcd集群节点因意外重启后，systemctl start etcd.service无法启动 停掉该etcd 备份此台etcd的数据 把此台etcd数据删除清空 把etcd配置由new改为existing systemctl start etcd.service ， 数据会同步至此台
