k8s提示certificate signed by unknown authority (possibly because of "crypto/rsa: verification error" while trying to verify candidate authority certificate "kubernetes")

原因：这是在重新创建集群之前，原来集群的rm -rf $HOME/.kube文件没有删除，所以导致了认证失去作用。

解决方法1：

1、删除这个路径下的文件

rm -rf $HOME/.kube

2、重新执行命令

mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config

3、重新查看节点

[root@master1 ~]# kubectl get nodes 
NAME      STATUS   ROLES                  AGE   VERSION
master1   Ready    control-plane,master   28m   v1.20.0
master2   Ready    control-plane,master   24m   v1.20.0
master3   Ready    control-plane,master   23m   v1.20.0
node1     Ready    <none>                 23m   v1.20.0

解决方法2：

echo export KUBECONFIG=/etc/kubernetes/kubelet.conf >> ~/.bashrc
source ~/.bashrc