ccah-500 第11题What does CDH packaging do on install to facilitate Kerberos security setup

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

A. Automatically configures permissions for log files at & MAPRED_LOG_DIR/userlogs

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

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

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

E. Creates and configures your kdc with default cluster values

Answer: B

reference：

选项D：

Cloudera Manager can automatically create and deploy a keytab file for the hdfs user and a keytab file for the mapred user on every host in your cluster, as well as keytab files for the oozie and hue users on select hosts。

 

选项B：

During CDH 5 package installation of MapReduce 2.0 (YARN), the following Unix user accounts are automatically created to support security:

This User	Runs These Hadoop Programs
hdfs	HDFS: NameNode, DataNodes, Standby NameNode (if you are using HA)
yarn	YARN: ResourceManager, NodeManager
mapred	YARN: MapReduce Job History Server

Important: The HDFS and YARN daemons must run as different Unix users; for example, hdfs and yarn.
The MapReduce Job History server must run as user mapred. Having all of these users share a common Unix group is recommended; for example,hadoop.

http://www.cloudera.com/documentation/enterprise/5-3-x/topics/cdh_sg_users_groups_verify.html