The connection to the server localhost:8080 was refused - did you specify the right host or port?

kubectl get pod
The connection to the server localhost:8080 was refused - did you specify the right host or port?
出现这个问题的原因是kubectl命令需要使用kubernetes-admin来运行，解决方法如下，将主节点中 /etc/kubernetes/admin.conf 文件拷贝到从节点相同目录下，然后配置环境变量：
echo "export KUBECONFIG=/etc/kubernetes/admin.conf" >> ~/.bash_profile
source ~/.bash_profile