public void getAndMergeHostConfigAttributes(Map<String, Map<String, Map<String, String>>> configurationAttributes,
                                     Map<String, Map<String, String>> configurationTags,
                                     Cluster cluster) {
    if (null != configurationTags && !configurationTags.isEmpty()) {
      Map<String, Map<String, Map<String, String>>> configAttributes =
          getEffectiveConfigAttributes(cluster, configurationTags);

      for (Map.Entry<String, Map<String, Map<String, String>>> attributesOccurrence : configAttributes.entrySet()) {
        String type = attributesOccurrence.getKey();
        Map<String, Map<String, String>> attributes = attributesOccurrence.getValue();

        if (configurationAttributes != null) {
          if (!configurationAttributes.containsKey(type)) {
            configurationAttributes.put(type,
                new TreeMap<>());
          }
          cloneAttributesMap(attributes,
              configurationAttributes.get(type));
        }
      }
    }
  }
Retrieves effective configuration attributes for specified cluster and tags and merge them with
present before in {@code configurationAttributes}
@param configurationAttributes configuration attributes will be merged with effective ones on the cluster
@param configurationTags  configuration tags for cluster's desired configs
@param cluster cluster to config attributes retrieving
ambari-server/src/main/java/org/apache/ambari/server/state/ConfigHelper.java