public void putResource(ResourceKey key, Resource resource) {
      clusterSet.add(key.getClusterName());
      hostSet.add(key.getHostName());
      Set<Resource> resourceSet = resources.get(key);
      if (resourceSet == null) {
        resourceSet = new HashSet<>();
        resources.put(key, resourceSet);
      }
      resourceSet.add(resource);
    }
The information required to make a single RRD request.
ambari-server/src/main/java/org/apache/ambari/server/controller/metrics/ganglia/GangliaPropertyProvider.java