k8s集群报错：The connection to the server localhost:8080 was refused

root@k8s-master:~# kubectl get node
The connection to the server localhost:8080 was refused - did you specify the right host or port?

原因：使用kubeadm安装的k8s集群的/etc/kubernetes/admin.conf 为设置环境变量

解决方法设置环境变量并设置系统启动生效，并设置立即生效：

root@k8s-master:~# echo "export KUBECONFIG=/etc/kubernetes/admin.conf" >> ~/.bash_profile
root@k8s-master:~# source ~/.bash_profile