private boolean isExtensionEnabled() {
    Map<String, String> supportsMap = getModuleInfo().getAttributes().get(ConfigurationInfo.Supports.KEYWORD);
    if (supportsMap == null) {
      return true;
    }

    String val = supportsMap.get(ConfigurationInfo.Supports.DO_NOT_EXTEND.getPropertyName());
    return val == null || val.equals("false");
  }
Determine if the configuration should extend the parents configuration.

@return true if this configuration should extend the parents; false otherwise
ambari-server/src/main/java/org/apache/ambari/server/stack/ConfigurationModule.java