Unable to connect to the server: x509: certificate signed by unknown authority

错误描述：

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1 2	[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：

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1	[root@k8s-master ~]# kubeadm reset

 

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1	[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：

 

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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：

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1	[root@k8s-master ~]# export KUBECONFIG=/etc/kubernetes/admin.conf

　　

如果当时是非root用户，执行如下：

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[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:

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[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！