include file ,exclude file permission clarification

[#1]

Hello All 

I am new to hadoop . 

using Hadoop 2.3.0-cdh5.0.0 

In the process of  adding and decommission of datanode in multi node cluster .

Read about the steps in the book. 

I really got stuck in the middle as to what permission(user:group) should be set for include and exclude file which should reside on the local system of the namenode running .

Also it will be much helpful if anyone can give me a example as to how include and exclude file will look. 

I assume we just need to add the Network address of the datanode cluster in each of the file.

Correct me if I am wrong.

Thanks

[#2]

Only read access for 'hdfs' and 'yarn' system users are needed. Default permissions are root:hadoop owner, 0644 mode.

Of course you need also dfs.hosts, yarn.resourcemanager.nodes.include-path properties (default values are empty, which means permit every host to be a worker node). And dfs.hosts.exclude, yarn.resourcemanager.nodes.exclude-path for the excludes.

The content can be hostnames or the network addresses.