private void addConfigTypePropVal(HashMap<String, Map<String, String>> configurations, String configType, String prop, String val) {
    Map<String, String> configTypePropsVal = configurations.get(configType);
    if (configTypePropsVal == null) {
      configTypePropsVal = new HashMap<>();
      configurations.put(configType, configTypePropsVal);
    }
    configTypePropsVal.put(prop, val);
    actionLog.writeStdOut(String.format("Setting property %s/%s: %s", configType, prop, (val == null) ? "<null>" : val));
  }
Adds a property to properties of a given service config type

@param configurations a map of configurations
@param configType     service config type
@param prop           property to be added
@param val            value for the property
ambari-server/src/main/java/org/apache/ambari/server/serveraction/kerberos/UpdateKerberosConfigsServerAction.java