1.查看当前证书时间
# kubeadm alpha certs renew kubelet
Kubeadm experimental sub-commands
kubeadm是一个用于引导Kubernetes集群的工具，它提供了许多命令和子命令来管理集群的一生周期。过去，某些功能被标记为实验性的，并通过kubeadm alpha子命令进行访问。然而，从Kubernetes 1.15版本开始，kubeadm将这些功能从alpha子命令迁移到了稳定的命令中。在新版本中，使用kubeadm certs renew kubelet即可
检查
# 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'
CERTIFICATE EXPIRES RESIDUAL TIME CERTIFICATE AUTHORITY EXTERNALLY MANAGED
admin.conf Mar 26, 2025 08:52 UTC 286d ca no
apiserver Mar 26, 2025 08:52 UTC 286d ca no
apiserver-etcd-client Mar 26, 2025 08:52 UTC 286d etcd-ca no
apiserver-kubelet-client Mar 26, 2025 08:52 UTC 286d ca no
controller-manager.conf Mar 26, 2025 08:52 UTC 286d ca no
etcd-healthcheck-client Mar 26, 2025 08:52 UTC 286d etcd-ca no
etcd-peer Mar 26, 2025 08:52 UTC 286d etcd-ca no
etcd-server Mar 26, 2025 08:52 UTC 286d etcd-ca no
front-proxy-client Mar 26, 2025 08:52 UTC 286d front-proxy-ca no
scheduler.conf Mar 26, 2025 08:52 UTC 286d ca no
CERTIFICATE AUTHORITY EXPIRES RESIDUAL TIME EXTERNALLY MANAGED
ca Mar 24, 2034 08:52 UTC 9y no
etcd-ca Mar 24, 2034 08:52 UTC 9y no
front-proxy-ca Mar 24, 2034 08:52 UTC 9y no kubelet证书时间只有1年有效期。
# openssl x509 -in kubelet.crt -noout -text | grep "Not"
Not Before: Mar 26 07:52:16 2024 GMT
Not After : Mar 26 07:52:16 2025 GMT备份原证书
# mkdir backup_certs
# cd backup_certs/
# cp /usr/bin/kube* .
# ll
total 211260
-rwxr-x--- 1 root root 45210392 Jun 13 15:15 kubeadm
-rwxr-x--- 1 root root 46592216 Jun 13 15:15 kubectl
-rwxr-x--- 1 root root 124521288 Jun 13 15:15 kubelet
# cp -r /etc/kubernetes/pki .
]# ll
total 211264
-rwxr-x--- 1 root root 45210392 Jun 13 15:15 kubeadm
-rwxr-x--- 1 root root 46592216 Jun 13 15:15 kubectl
-rwxr-x--- 1 root root 124521288 Jun 13 15:15 kubelet
drwxr-x--- 3 root root 4096 Jun 13 15:18 pki删除旧证书
# rm -rf /etc/kubernetes/pki/*生成新证书
# kubeadm certs renew -h
This command is not meant to be run on its own. See list of available subcommands.
Usage:
kubeadm certs renew [flags]
kubeadm certs renew [command]
Available Commands:
admin.conf Renew the certificate embedded in the kubeconfig file for the admin to use and for kubeadm itself
all Renew all available certificates
apiserver Renew the certificate for serving the Kubernetes API
apiserver-etcd-client Renew the certificate the apiserver uses to access etcd
apiserver-kubelet-client Renew the certificate for the API server to connect to kubelet
controller-manager.conf Renew the certificate embedded in the kubeconfig file for the controller manager to use
etcd-healthcheck-client Renew the certificate for liveness probes to healthcheck etcd
etcd-peer Renew the certificate for etcd nodes to communicate with each other
etcd-server Renew the certificate for serving etcd
front-proxy-client Renew the certificate for the front proxy client
scheduler.conf Renew the certificate embedded in the kubeconfig file for the scheduler manager to use
Flags:
-h, --help help for renew
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)
--one-output If true, only write logs to their native severity level (vs also writing to each lower severity level)
--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
Use "kubeadm certs renew [command] --help" for more information about a command.生成某个证书
升级哪个证书，就生成哪个组件的证书，保险，就生成所有证书
# kubeadm certs renew apiserver-kubelet-client
[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'
certificate for the API server to connect to kubelet renewed生成所有证书
# 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'
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.查看配置已经更新
# ll /etc/kubernetes/
total 32
-rwxrwxrwx 1 root root 5640 Jun 13 15:26 admin.conf
-rw------- 1 root root 5668 Jun 13 15:26 controller-manager.conf
-rw------- 1 root root 2004 Mar 26 16:52 kubelet.conf
drwxr-xr-x 2 root root 113 May 29 17:12 manifests
drwxr-x--- 3 root root 4096 Mar 26 16:52 pki
-rw------- 1 root root 5620 Jun 13 15:26 scheduler.conf生成新配置
查看帮助
# kubeadm init phase kubeconfig -h
This command is not meant to be run on its own. See list of available subcommands.
Usage:
kubeadm init phase kubeconfig [flags]
kubeadm init phase kubeconfig [command]
Available Commands:
admin Generate a kubeconfig file for the admin to use and for kubeadm itself
all Generate all kubeconfig files
controller-manager Generate a kubeconfig file for the controller manager to use
kubelet Generate a kubeconfig file for the kubelet to use *only* for cluster bootstrapping purposes
scheduler Generate a kubeconfig file for the scheduler to use
Flags:
-h, --help help for kubeconfig
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)
--one-output If true, only write logs to their native severity level (vs also writing to each lower severity level)
--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
Use "kubeadm init phase kubeconfig [command] --help" for more information about a command.生成某个配置
失败是正常，版本垮裤较大，而且也只更新证书有效期
# kubeadm init phase kubeconfig admin
I0613 15:31:07.518079 30859 version.go:255] remote version is much newer: v1.30.2; falling back to: stable-1.23
W0613 15:31:17.521449 30859 version.go:103] could not fetch a Kubernetes version from the internet: unable to get URL "https://dl.k8s.io/release/stable-1.23.txt": Get "https://cdn.dl.k8s.io/release/stable-1.23.txt": context deadline exceeded (Client.Timeout exceeded while awaiting headers)
W0613 15:31:17.521573 30859 version.go:104] falling back to the local client version: v1.23.4生成所有配置
# kubeadm init phase kubeconfig all
W0613 15:45:39.731181 7842 version.go:103] could not fetch a Kubernetes version from the internet: unable to get URL "https://dl.k8s.io/release/stable-1.txt": Get "https://cdn.dl.k8s.io/release/stable-1.txt": context deadline exceeded (Client.Timeout exceeded while awaiting headers)
W0613 15:45:39.731479 7842 version.go:104] falling back to the local client version: v1.23.4
[kubeconfig] Using kubeconfig folder "/etc/kubernetes"
[kubeconfig] Using existing kubeconfig file: "/etc/kubernetes/admin.conf"
[kubeconfig] Using existing kubeconfig file: "/etc/kubernetes/kubelet.conf"
[kubeconfig] Using existing kubeconfig file: "/etc/kubernetes/controller-manager.conf"
[kubeconfig] Using existing kubeconfig file: "/etc/kubernetes/scheduler.conf"重启kubelet
# systemctl status kubelet.service | grep Active
Active: active (running) since Tue 2024-03-26 16:52:52 CST; 2 months 18 days ago
# systemctl restart kubelet.service
# systemctl status kubelet.service | grep Active
Active: active (running) since Thu 2024-06-13 15:47:19 CST; 3s ago更新admin.conf文件
# cp /etc/kubernetes/admin.conf ~/.kube/config
cp: overwrite ‘/root/.kube/config’? y2.检查证书有效期
# 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'
CERTIFICATE EXPIRES RESIDUAL TIME CERTIFICATE AUTHORITY EXTERNALLY MANAGED
admin.conf Jun 13, 2025 07:26 UTC 364d ca no
apiserver Jun 13, 2025 07:26 UTC 364d ca no
apiserver-etcd-client Jun 13, 2025 07:26 UTC 364d etcd-ca no
apiserver-kubelet-client Jun 13, 2025 07:26 UTC 364d ca no
controller-manager.conf Jun 13, 2025 07:26 UTC 364d ca no
etcd-healthcheck-client Jun 13, 2025 07:26 UTC 364d etcd-ca no
etcd-peer Jun 13, 2025 07:26 UTC 364d etcd-ca no
etcd-server Jun 13, 2025 07:26 UTC 364d etcd-ca no
front-proxy-client Jun 13, 2025 07:26 UTC 364d front-proxy-ca no
scheduler.conf Jun 13, 2025 07:26 UTC 364d ca no
CERTIFICATE AUTHORITY EXPIRES RESIDUAL TIME EXTERNALLY MANAGED
ca Mar 24, 2034 08:52 UTC 9y no
etcd-ca Mar 24, 2034 08:52 UTC 9y no
front-proxy-ca Mar 24, 2034 08:52 UTC 9y no 查看各证书时间
# openssl x509 -in /etc/kubernetes/pki/apiserver.crt -noout -text
Not Before: Mar 26 08:52:10 2024 GMT
Not After : Jun 13 07:26:54 2025 GMT
# openssl x509 -in /etc/kubernetes/pki/apiserver-etcd-client.crt -noout -text
Not Before: Mar 26 08:52:11 2024 GMT
Not After : Jun 13 07:26:55 2025 GMT
# openssl x509 -in /etc/kubernetes/pki/apiserver-kubelet-client.crt -noout -text
Not Before: Mar 26 08:52:10 2024 GMT
Not After : Jun 13 07:26:55 2025 GMT
# openssl x509 -in /etc/kubernetes/pki/ca.crt -noout -text
Not Before: Mar 26 08:52:10 2024 GMT
Not After : Mar 24 08:52:10 2034 GMT
# openssl x509 -in /etc/kubernetes/pki/front-proxy-ca.crt -noout -text
Not Before: Mar 26 08:52:10 2024 GMT
Not After : Mar 24 08:52:10 2034 GMT
# openssl x509 -in /etc/kubernetes/pki/front-proxy-client.crt -noout -text
Not Before: Mar 26 08:52:10 2024 GMT
Not After : Jun 13 07:26:57 2025 GMT查看k8s环境
