Storing and Configuring Data with Hadoop, YARN, and ZooKeeper - Big Data Made Easy: A Working Guide to the Complete Hadoop Toolset - page 41

Use the ls command to view the configuration files that need to be altered:
[root@hc1nn conf]# cd /etc/hadoop/conf
[root@hc1nn conf]# ls -l *-site.xml
-rw-r--r--. 1 root root 904 Feb 26 23:17 core-site.xml
-rw-r--r--. 1 root root 1023 Feb 26 23:17 hdfs-site.xml
-rw-r--r--. 1 root root 904 Feb 26 23:17 mapred-site.xml
-rw-r--r--. 1 root root 2262 Feb 26 23:17 yarn-site.xml
On each node, set up the core-site.xml as follows:
<configuration>
<property>
<name>fs.defaultFS</name>
<value>hdfs://hc1nn/</value>
</property>
</configuration>
You need hdfs-site.xml on each node, as well. To set it up, use the form:
<configuration>
<property>
<name>dfs.namenode.name.dir</name>
<value>/var/lib/hadoop-hdfs/cache/hdfs/dfs/name</value>
<description> Can be a comma separated list of values </description>
</property>
<property>
<name>dfs.permissions.superusergroup</name>
<value>hadoop</value>
</property>
<property>
<name>dfs.replication</name>
<value>2</value>
</property>
</configuration>
Remember, however, to define dfs.namenode.name.dir on the name node and dfs.datanode.data.dir on the data
node. So, the entry for the data nodes would be as follows:
<property>
<name>dfs.datanode.name.dir</name>
<value>/var/lib/hadoop-hdfs/cache/hdfs/dfs/name</value>
<description> Can be a comma separated list of values </description>
</property>