Sample readonly role setting not working for ES 7.7

[ensean]

Following the guide here I create a readonly user on a ES 7.7 cluster, but when I logged in with a new internal user with the readonly role, I can not view the indices created by the master user(internal user)

BTW, the guide for readonly role setting up seems not to be matched with ES 7.7...

Is it possible to setting up a readonly user/role in ES 7.7 ？