错误描述：
[root@k8s-master ~]# kubectl get nodes Unable to connect to the server: x509: certificate signed by unknown authority (possibly because of "crypto/rsa: verification error" while trying to verify candidate authority certificate "kubernetes")
一般是：k8s master 初始化操作不完整导致，完整过程如下：
[root@k8s-master ~]# kubeadm reset
[root@k8s-master ~]# kubeadm init --apiserver-advertise-address=192.168.58.138 --kubernetes-version v1.23.5 --pod-network-cidr=192.168.0.0/16
看到如下提示信息后要继续执行：
Your Kubernetes control-plane has initialized successfully! To start using your cluster, you need to run the following as a regular user: mkdir -p $HOME/.kube sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config sudo chown $(id -u):$(id -g) $HOME/.kube/config Alternatively, if you are the root user, you can run: export KUBECONFIG=/etc/kubernetes/admin.conf You should now deploy a pod network to the cluster. Run "kubectl apply -f [podnetwork].yaml" with one of the options listed at: https://kubernetes.io/docs/concepts/cluster-administration/addons/ Then you can join any number of worker nodes by running the following on each as root: kubeadm join 192.168.58.138:6443 --token ngpadd.js4es78t13mi9cjd \ --discovery-token-ca-cert-hash sha256:a72b70060492ad11c2034db603c6d58b069d18a7aa44cd8903ccb383ffdb342a
如果当前是 root 用户，执行如下：
[root@k8s-master ~]# export KUBECONFIG=/etc/kubernetes/admin.conf
如果当时是非root用户，执行如下：
[root@k8s-master ~]#mkdir -p $HOME/.kube [root@k8s-master ~]#sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config [root@k8s-master ~]#sudo chown $(id -u):$(id -g) $HOME/.kube/config
再次执行:
[root@k8s-master ~]# kubectl get nodes NAME STATUS ROLES AGE VERSION k8s-master Ready control-plane,master 106m v1.23.5 k8s-node1 Ready <none> 97m v1.23.5
问题解决，希望能帮到您！
