证书过期
[root@k8s-master ~]$ kubectl get node
Unable to connect to the server: x509: certificate has expired or is not yet valid: current time 2022-09-15T10:27:07+08:00 is after 2022-09-15T02:17:20Z
[root@k8s-master ~]$ kubeadm certs renew all # 更新证书,更新完后会提示重启kube-apiserver, kube-controller-manager,