How to restrict nodes that talk to namenode

Question

I want to restrict the nodes that talk to the namenode. I want to set an include file, so that no other nodes can talk to the namenode, other than the nodes that are mentioned in the include file. How can I do this?

Comments

Is this restricted only to Hadoop platform? Is a similar file present in other tools also? Like if i'm dealing with puppet agents and Docker nodes...

Answer 1

Step 1: Create includes file in /home/hadoop directory.

Step 2: Update Hdfs-site.xml add the following property

<property>
<name>dfs.hosts</name>
<value>/home/hadoop/includes</value>
<final>true</final>
</property>

Step 3: Update mapred-site.xml 

<property>
<name>mapred.hosts</name>
<value>/home/hadoop/includes</value>
<final>true</final>
</property>

Step 4:  Run below command to refresh the nodes

hadoop dfsadmin -refreshNodes

Step 5: Run report command to see the list of nodes

hadoop dfsadmin -report