更新kubeadm kubernets平台证书

证书过期失效：

Unable to connect to the server: x509: certificate has expired or is not yet valid

更新证书：

1、查看证书是否过期

cd /etc/kubernetes/pki
openssl x509 -in apiserver.crt -noout -text |grep ' Not '   # 查看是否过期
kubeadm alpha certs check-expiration   #检查k8s环境证书是否过期

2、更新证书

（1） 备份一下 /etc /kubernetes /pki 目录下的所有文件

（2）更新证书

kubeadm alpha certs renew all

（3）查看证书有效期是否更新

openssl x509 -in apiserver.crt -noout -text |grep ' Not '

3、在master节点上将/etc/kubernetes目录下的所有配置文件备份

4、更新用户配置

kubeadm alpha kubeconfig user --client-name=admin
kubeadm alpha kubeconfig user --org system:masters --client-name kubernetes-admin  > /etc/kubernetes/admin.conf
kubeadm alpha kubeconfig user --client-name system:kube-controller-manager > /etc/kubernetes/controller-manager.conf
kubeadm alpha kubeconfig user --org system:nodes --client-name system:node:$(hostname) > /etc/kubernetes/kubelet.conf
kubeadm alpha kubeconfig user --client-name system:kube-scheduler > /etc/kubernetes/scheduler.conf

5、用更新后的admin.conf替换/root/.kube/config文件

cp -i /etc/kubernetes/admin.conf $HOME/.kube/config

6、重启所有master节点上的apiserver和scheduler两个系统组件

docker ps |grep -E 'k8s_kube-apiserver|k8s_kube-scheduler'|xargs docker restart

7、更新jenkins服务器adminconfig.conf配置（如果有jenkins发布的话）

修改jenkins的helm配置文件adminconfig.conf

环境变量

export KUBECONFIG=/opt/helm/kubeconfig/adminconfig.conf