現象：

 kubectl get nodes執行報錯：

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")

問題：

/root/.kube/config證書認證錯誤，使用正確證書，可能是kubeadm reset證書未刪除

解決辦法

刪除原來的證書及緩存文件

#rm -rf  /root/.kube/*

拷貝master節點上證書到目錄即可