kubectl 命令执行报错：(Unable to connect to the server: x509: certificate signed by unknown authority )

现象：
kubectl get nodes执行报错：

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")

问题：
/root/.kube/config证书认证错误，使用正确证书，可能是kubeadm reset证书未删除
解决办法
删除原来的证书及缓存文件
#rm -rf /root/.kube/*

拷贝master节点上证书到目录即可

kubectl 命令执行报错：(Unable to connect to the server: x509: certificate signed by unknown authority )最先出现在Python成神之路。