This is the documentation for CDH 4.7.0.
Documentation for other versions is available at Cloudera Documentation.

Step 6: Enable Hadoop Security

Cloudera recommends that all of the Hadoop configuration files throughout the cluster have the same contents.

To enable Hadoop security, add the following properties to the core-site.xml file on every machine in the cluster:

<property>
  <name>hadoop.security.authentication</name>
  <value>kerberos</value> <!-- A value of "simple" would disable security. -->
</property>

<property>
  <name>hadoop.security.authorization</name>
  <value>true</value>
</property>