K8s更新apiserver，允许域名方式访问

导出当前集群的配置文件

kubectl -n kube-system get configmap kubeadm-config -o jsonpath='{.data.ClusterConfiguration}' > kubeadm.yaml

将导出的集群配置文件备份

cp kubeadm.yaml kubeadm.yaml.bak

修改集群配置文件

修改kubeadm.yaml为如下配置

apiServer:
  certSANs:
   - "192.168.0.184"  # 添加需要签名的域名
   - "www.k8s.cn"
  extraArgs:
    authorization-mode: Node,RBAC
  timeoutForControlPlane: 4m0s
apiVersion: kubeadm.k8s.io/v1beta3
certificatesDir: /etc/kubernetes/pki
clusterName: kubernetes
controllerManager: {}
dns: {}
etcd:
  local:
    dataDir: /var/lib/etcd
imageRepository: registry.aliyuncs.com/google_containers
kind: ClusterConfiguration
kubernetesVersion: v1.28.0
networking:
  dnsDomain: cluster.local
  podSubnet: 10.244.0.0/16
  serviceSubnet: 10.96.0.0/12
scheduler: {}

将原来的apiserver证书配置文件备份

mkdir -p /etc/kubernetes/pki/backup
mv /etc/kubernetes/pki/apiserver.{crt,key} /etc/kubernetes/pki/backup/

生成新的apiserver 证书文件

[root@node1 ~]# kubeadm init phase certs apiserver --config kubeadm.yaml
[certs] Generating "apiserver" certificate and key
[certs] apiserver serving cert is signed for DNS names [kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local node1 www.k8s.cn] and IPs [10.96.0.1 192.168.0.184]

更新~/.kube/config文件

将新生成的/etc/kubernetes/admin.conf拷贝到$HOME/.kube/config

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

代码测试

提前修改测试主机的hosts文件，将www.k8s.cn指向k8s apiserver的地址，然后执行如下go代码

package main

import (
    "context"
    "fmt"
    metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
    "k8s.io/client-go/kubernetes"
    "k8s.io/client-go/tools/clientcmd"
    "os"
)

func main() {
    projectDir, _ := os.Getwd()
    config, err := clientcmd.BuildConfigFromFlags("https://www.k8s.cn:6443", projectDir+"/kubeconfig")
    if err != nil {
       panic(err)
    }

    clientset, err := kubernetes.NewForConfig(config)

    if err != nil {
       panic(err)
    }

    result, err := clientset.CoreV1().Pods("default").List(context.TODO(), metav1.ListOptions{Limit: 500})

    if err != nil {
       panic(err)
    }

    for _, item := range result.Items {
       fmt.Printf("namespace: %v\t name: %v\t status: %+v\n", item.Namespace, item.Name, item.Status.Phase)
    }

}

参考文档

• blog.csdn.net/lwlfox/arti…