Auth in HDFS.
If Hadoop is configured with all of its defaults, Hadoop doesn’t do any authentication of users.
See also: Permission
In hdfs, a user or group are just strings of characters. The below command will always work.
hadoop fs -chown badUser:badGroup /test
No one will be able to access that file except the adminusers
User identity mechanism is specified by the configuration property: hadoop.security.authentication
The user is the Linux user. The below command will be processed with the user userName
sudo -u userName hadoop fs ls /
Kerberos is an authentication protocol which uses tickets to allow nodes to identify themselves.
In a secure Hadoop configuration, all of the Hadoop daemons use Kerberos to perform mutual authentication
hdfs getconf -confKey hadoop.security.authentication
simple