What does CDH packaging do on install to facilitate Kerberos security setup?

A.
Automatically configure permissions for log files at $MAPPED_LOG_DIR/userlogs

B.
Creates and configures you kdc with default cluster values.

C.
Creates users for hdfs and mapreduce to facilitate role assignment.

D.
Creates a set of pre-configured Kerberos keytab files and their permissions.

E.
Creates directories for temp, hdfs, and mapreduce with correct permissions.

Explanation:
During CDH4 package installation of MRv1, the following Unix user accounts are
automatically created to support security:
This User, Runs These Hadoop Programs
hdfs HDFS: NameNode, DataNodes, Secondary NameNode, Standby NameNode (if you are
using HA)
mapredMRv1: JobTracker and TaskTrackers
Configuring Hadoop Security in CDH4