1. Set up a Hostmap Provider

Add tthe hostmap provider to the cluster topology descriptor and a parameter for each DataNode in the cluster, as follows:

Open the cluster topology descriptor file, $cluster-name.xml, in a text editor.
Add the Hostmap provider to topology/gateway using the following format:
```
<provider>
   <role>hostmap</role>
   <name>static</name>
   <enabled>true</enabled>
   <param>
     <name>$external-name</name>
     <value>$internal-dn-host</value>
   </param>
</provider>
```
where:
- $cluster-name.xml is the name of the topology descriptor file, located in /etc/knox/conf/topologies .
- $external-name is the value that the gateway uses to replace $internal_host host names in responses.
- $internal-dn-host is a comma separated list of host names that the gateway will replace when rewriting responses.
To the hostmap provider, add a param for each additional DataNode in your cluster:
```
<param>
   <name>$external-name2</name>
   <value>$internal-dn2-host</value>
</param>
```
Save the file.
The gateway creates a new WAR file with modified timestamp in /var/lib/knox/data/deployments .