更新集群证书

下载cfssl工具

https://pkg.cfssl.org/

查看当前证书到期时间

[root@ip-10-1-14-230 ~]# ./cfssl-certinfo_linux-amd64 -cert /etc/kubernetes/pki/apiserver.crt | grep not
  "not_before": "2019-08-23T08:46:31Z",
  "not_after": "2020-08-22T09:46:54Z",

更新证书

[root@ip-10-1-14-230 ~]# kubeadm alpha certs renew all
certificate embedded in the kubeconfig file for the admin to use and for kubeadm itself renewed
certificate for serving the Kubernetes API renewed
certificate the apiserver uses to access etcd renewed
certificate for the API server to connect to kubelet renewed
certificate embedded in the kubeconfig file for the controller manager to use renewed
certificate for liveness probes to healtcheck etcd renewed
certificate for etcd nodes to communicate with each other renewed
certificate for serving etcd renewed
certificate for the front proxy client renewed
certificate embedded in the kubeconfig file for the scheduler manager to use renewed

查看新的到期时间

[root@ip-10-1-14-230 ~]# ./cfssl-certinfo_linux-amd64 -cert /etc/kubernetes/pki/apiserver.crt | grep not
  "not_before": "2019-08-23T08:46:31Z",
  "not_after": "2020-08-28T06:26:32Z",