I need to know if there is a way to create a hdfs/hadoop or hive user via Ranger, not via shell. I can provide or deny access to hdfs folders or files, hive tables or columns, but to the users that already exists.
Ranger does not have any facility to create hadoop users in the nodes. If there are hadoop users which you want to authorize you can use Ranger Usersync to bring those into Ranger or in Ranger Admin UI you can create that user ( Settings-->Users/Groups-->Add new user) like kvarakantham had mentioned in the previous post. This enables you to create policy against those users.
My Ranger is already configured with Usersync, I can see that users that were created and give them permissions. My biggest question is if the user that i create on Ranger are only internal to Ranger or they can access hdfs, hive, etc...
That is correct, I guess I wasn't clear. Adding the user in Hue will take care of generating the user home in HDFS, but you will still need to drop to the shell to create the local user in linux. This will become cumbersome for larger clusters and is only realistic for small test clusters.
Ideally you will want to use ldap to manage your users. Whether that means using an enterprise LDAP/AD or using a tool like freeIPA and its web UI combined with Kerberos. Together these will provide you with very secure authentication while also providing a GUI to create users which can be sync'd to Ranger.