Which two features does Kerberos security add to a Hadoop cluster?

A.
Authentication for user access to the cluster against a central server

B.
Encryption for data on disk (“at rest”)

C.
Encryption on all remote procedure calls (RPCs)

D.
User authentication on all remote procedure calls (RPcs)

E.
Root access to the cluster for users hdfs and mapred but non-root acess clients

Explanation:
C (not B): It should be noted that CDH3 does not support data encryption. RPC data
may be encrypted on the wire, but actual user data is not encrypted and there is no built-in support
foron-disk encryption. For most current Hadoop users, this lack of data encryption is acceptable
because of the assumptions stated above.
D: The Hadoop daemons leverage Kerberos to perform user authentication on all remote
procedure calls (RPCs).
Reference:
Documentation CDH3 Documentation CDH3 Security Guide, Introduction to Hadoop
Security