The connection to the server 172.30.1.2:6443 was refused - did you specify the right host or port?
1.查看/var/log/syslog日志，grep apiserver。查看错误日志信息，根据提示修改配置文件（如kube-apiserver.yaml）
2.去查看组件pod日志
/var/log/pods/kube-apiserver/../log
3.service restart kubelet