自建K8S集群认证过期 【转】

今天使用kubectl命令查看pod信息时，一直正常运行的k8s集群突然不能访问了，输入任何命令都提示以下报错：
Unable to connect to the server: x509: certificate has expired or is not yet valid: current time 2025-01-25T11:35:45+08:00 is after 2024-11-22T23:44:48Z

解决方案：

参考官方文档： kubeadm证书管理 使用命令kubeadm alpha certs来管理证书：

1. 使用命令kubeadm alpha certs renew all更新证书，返回

[renew] Reading configuration from the cluster...

[renew] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -oyaml'

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

2. 使用如下命令拷贝新生成的配置文件

sudo kubeadm alpha kubeconfig user --client-name=admin --org=system:masters > /tmp/admin.conf

sudo cp /tmp/admin.conf $HOME/.kube/config

sudo chown $(id -u):$(id -g) $HOME/.kube/config

3. 重启kubeletsystemctl restart kubelet 即可正常使用K8S集群

[root@k8smaster k8s]# kubectl get po

NAME READY STATUS RESTARTS AGE

cron-job-test-1732318920-k2g76 0/1 Completed 0 63d

cron-job-test-1732318980-kcr4x 0/1 Completed 0 63d

cron-job-test-1732319040-b88rf 0/1 Completed 0 63d

4. 再次查看证书到期情况

[root@k8smaster k8s]# kubeadm alpha 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 -oyaml'

CERTIFICATE EXPIRES RESIDUAL TIME CERTIFICATE AUTHORITY EXTERNALLY MANAGED

admin.conf Jan 25, 2026 05:55 UTC 364d no

apiserver Jan 25, 2026 05:55 UTC 364d ca no

apiserver-etcd-client Jan 25, 2026 05:55 UTC 364d etcd-ca no

apiserver-kubelet-client Jan 25, 2026 05:55 UTC 364d ca no

controller-manager.conf Jan 25, 2026 05:55 UTC 364d no

etcd-healthcheck-client Jan 25, 2026 05:55 UTC 364d etcd-ca no

etcd-peer Jan 25, 2026 05:55 UTC 364d etcd-ca no

etcd-server Jan 25, 2026 05:55 UTC 364d etcd-ca no

front-proxy-client Jan 25, 2026 05:55 UTC 364d front-proxy-ca no

scheduler.conf Jan 25, 2026 05:55 UTC 364d no

CERTIFICATE AUTHORITY EXPIRES RESIDUAL TIME EXTERNALLY MANAGED

ca Nov 20, 2033 23:44 UTC 8y no

etcd-ca Nov 20, 2033 23:44 UTC 8y no

front-proxy-ca Nov 20, 2033 23:44 UTC 8y no

注意事项：

官网上给的命令是kubeadm certs check-expiration，标识的k8s版本是V1.15，直接在本地执行该命令报错：

[root@k8smaster k8s]# kubeadm certs check-expiration

unknown command "certs" for "kubeadm"

To see the stack trace of this error execute with --v=5 or higher

查了下，我本地的k8s版本是1.19，certs命令放在了 kubeadm alpha下，需要将kubeadm certs替换为 kubeadm aplha certs执行即可

[root@k8smaster k8sh]# kubeadm version

kubeadm version: &version.Info{Major:"1", Minor:"19", GitVersion:"v1.19.5", GitCommit:"e338cf2c6d297aa603b50ad3a301f761b4173aa6", GitTreeState:"clean", BuildDate:"2020-12-09T11:16:40Z", GoVersion:"go1.15.2", Compiler:"gc", Platform:"linux/amd64"}

[root@k8smaster k8s]# kubeadm --help

┌──────────────────────────────────────────────────────────┐

│ KUBEADM │

│ Easily bootstrap a secure Kubernetes cluster │

│ │

│ Please give us feedback at: │

│ https://github.com/kubernetes/kubeadm/issues │

└──────────────────────────────────────────────────────────┘

Example usage:

Create a two-machine cluster with one control-plane node

(which controls the cluster), and one worker node

(where your workloads, like Pods and Deployments run).

┌──────────────────────────────────────────────────────────┐

│ On the first machine: │

├──────────────────────────────────────────────────────────┤

│ control-plane# kubeadm init │

└──────────────────────────────────────────────────────────┘

┌──────────────────────────────────────────────────────────┐

│ On the second machine: │

├──────────────────────────────────────────────────────────┤

│ worker# kubeadm join <arguments-returned-from-init> │

└──────────────────────────────────────────────────────────┘

You can then repeat the second step on as many other machines as you like.

Usage:

kubeadm [command]

Available Commands:

alpha Kubeadm experimental sub-commands

completion Output shell completion code for the specified shell (bash or zsh)

config Manage configuration for a kubeadm cluster persisted in a ConfigMap in the cluster

help Help about any command

init Run this command in order to set up the Kubernetes control plane

join Run this on any machine you wish to join an existing cluster

reset Performs a best effort revert of changes made to this host by 'kubeadm init ' or 'kubeadm join'

token Manage bootstrap tokens

upgrade Upgrade your cluster smoothly to a newer version with this command

version Print the version of kubeadm

Flags:

--add-dir-header If true, adds the file directory to the header of the lo g messages

-h, --help help for kubeadm

--log-file string If non-empty, use this log file

--log-file-max-size uint Defines the maximum size a log file can grow to. Unit is megabytes. If the value is 0, the maximum file size is unlimited. (default 1800)

--rootfs string [EXPERIMENTAL] The path to the 'real' host root filesyst em.

--skip-headers If true, avoid header prefixes in the log messages

--skip-log-headers If true, avoid headers when opening log files

-v, --v Level number for the log level verbosity

Use "kubeadm [command] --help" for more information about a command.

[root@k8smaster k8s]# kubectl alpha --help

These commands correspond to alpha features that are not enabled in Kubernetes

clusters by default.

Available Commands:

debug Attach a debug container to a running pod

Use "kubectl <command> --help" for more information about a given command.

[root@k8smaster k8s]# kubeadm alpha --help

Kubeadm experimental sub-commands

Usage:

kubeadm alpha [command]

Available Commands:

certs Commands related to handling kubernetes certificates

kubeconfig Kubeconfig file utilities

selfhosting Make a kubeadm cluster self-hosted

Flags:

-h, --help help for alpha

Global Flags:

--add-dir-header If true, adds the file directory to the header of the log messages

--log-file string If non-empty, use this log file

--log-file-max-size uint Defines the maximum size a log file can grow to. Unit is megabytes. If the value is 0, the maximum file size is unlimited. (default 1800)

--rootfs string [EXPERIMENTAL] The path to the 'real' host root filesystem.

--skip-headers If true, avoid header prefixes in the log messages

--skip-log-headers If true, avoid headers when opening log files

-v, --v Level number for the log level verbosity

Additional help topics:

kubeadm alpha phase Invoke subsets of kubeadm functions separately for a manual install

Use "kubeadm alpha [command] --help" for more information about a command.

自建K8S集群认证过期 - wenha - 博客园
https://www.cnblogs.com/wenha/p/18690938