使用kubeadm部署的集群证书过期后处理

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之前使用 kubeadm 部署的集群，突然有一天执行 kubectl get pod 提示：

1	Unable to connect to the server: x509: certificate has expired or is not yet valid: current time 2024-03-04T14:26:31+08:00 is after 2024-02-27T08:36:50Z

意思是证书有效期到 2024-02-27T08:36:50Z， 已经超过了证书有效期了。
查看证书有效期

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[root@ALSHBSITL00061 kubernetes]# kubeadm certs check-expiration [check-expiration] Reading configuration from the cluster... [check-expiration] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -o yaml' [check-expiration] Error reading configuration from the Cluster. Falling back to default configuration CERTIFICATE                EXPIRES                  RESIDUAL TIME   CERTIFICATE AUTHORITY   EXTERNALLY MANAGED admin.conf                 Feb 27, 2024 08:36 UTC          ca                      no apiserver                  Feb 27, 2024 08:36 UTC          ca                      no apiserver-etcd-client      Feb 27, 2024 08:36 UTC          etcd-ca                 no apiserver-kubelet-client   Feb 27, 2024 08:36 UTC          ca                      no controller-manager.conf    Feb 27, 2024 08:36 UTC          ca                      no etcd-healthcheck-client    Feb 27, 2024 08:36 UTC          etcd-ca                 no etcd-peer                  Feb 27, 2024 08:36 UTC          etcd-ca                 no etcd-server                Feb 27, 2024 08:36 UTC          etcd-ca                 no front-proxy-client         Feb 27, 2024 08:36 UTC          front-proxy-ca          no scheduler.conf             Feb 27, 2024 08:36 UTC          ca                      no CERTIFICATE AUTHORITY   EXPIRES                  RESIDUAL TIME   EXTERNALLY MANAGED ca                      Feb 24, 2033 08:36 UTC   8y              no etcd-ca                 Feb 24, 2033 08:36 UTC   8y              no front-proxy-ca          Feb 24, 2033 08:36 UTC   8y              no

执行续期操作

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[root@ALSHBSITL00061 kubernetes]# kubeadm certs renew all [renew] Reading configuration from the cluster... [renew] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -o yaml' [renew] Error reading configuration from the Cluster. Falling back to default configuration 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 healthcheck 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 Done renewing certificates. You must restart the kube-apiserver, kube-controller-manager, kube-scheduler and etcd, so that they can use the new certificates.

更新 kubectl 配置

如果当时安装的时候是通过 cp /etc/kubernetes/admin.conf ~/.kube/config 复制的配置，需要再更新一遍，管理员也可以指定使用 /etc/kubernetes/admin.conf 作为 kubeconfig，就不用每次更新了。
重启服务

需要重启 kube-apiserver, kube-controller-manager, kube-scheduler 和 etcd， kubeadm 安装的 kubelet 会自动更新证书，所以不用重启。

1	crictl pods --namespace kube-system --name 'kube-scheduler-*|kube-controller-manager-*|kube-apiserver-*|etcd-*' -q | xargs crictl rmp -f

1 2	docker ps docker restart xxx