I enable the Ranger plugin for HDFS, but a Policy does not show up in Ranger. Are there any logs that I can look at to see why this is happening or is it a known issue?
There's no known issue that I'm aware of. When you install the plugin, you'll likely need to restart any affected services and then also it is a good idea to refresh the Ranger UI (sometimes just logging out/in isn't good enough, try the CTL+SHIFT+R browser refresh).
That is odd, the only time i've seen it is a browser refresh issue like I mentioned. As far as logs go, on the Ranger Admin server you can check /var/log/ranger/admin/xa_portal.log and see if any errors are in there.