kubectl exec 遇到Error from server forbidden问题

问题：

[[email protected] yaml_all]# kubectl get po
NAME                     READY   STATUS    RESTARTS   AGE
Nginx-648b5cc477-7b5pt   1/1     Running   0          3h41m
Nginx-648b5cc477-mplmg   1/1     Running   0          3h41m
Nginx-648b5cc477-zw8jq   1/1     Running   0          3h41m

执行下面这条后报错了

[[email protected] yaml_all]# kubectl exec -it Nginx-648b5cc477-7b5pt bash
error: unable to upgrade connection: Forbidden (user=system:anonymous,verb=create,resource=nodes,subresource=proxy)

临时解决方法：
绑定一个cluster-admin的权限

[[email protected] yaml_all]# kubectl create clusterrolebinding system:anonymous --clusterrole=cluster-admin --user=system:anonymous
clusterrolebinding.rbac.authorization.k8s.io/system:anonymous created

[[email protected] yaml_all]# kubectl exec -it Nginx-648b5cc477-7b5pt -- bash 
[email protected]:/# ls
bin  boot  dev  etc  home  lib  lib64  media  mnt  opt  proc  root  run  sbin  srv  sys  tmp  usr  var
[email protected]:/# exit
exit