Error saving changes: MapR client needs to be configured with the resource-manager address

Problem

When configuring Datameer to connect to a MapR cluster, the following error is displayed in the GUI when a user tries to save the new connection: 

Error saving changes: MapR client needs to be configured with the resource-manager address! (Expecting yarn.resourcemanager.hostname in /opt/mapr/hadoop/hadoop-2.5.1/etc/hadoop/yarn-site.xml)

Cause

The MapR client is not configured properly. As of MapR 4, YARN must be configured for Datameer to connect to it.

Solution

To resolve this issue, please update the referenced yarn-site.xml file from the error message. Be sure that the yarn.resourcemanager.hostname property is present and points to the appropriate hostname for the YARN Resource Manager.