public String getCommandParameterValue(String propertyName) {
      Map<String, String> commandParameters = params;
      return (commandParameters == null) ? null : commandParameters.get(propertyName);
    }
Retrieve the current set of properties for the requested config type for the relevant cluster.

@return a Map of property names to property values for the requested config type; or null if no data is found
@throws AmbariException if an error occurs retrieving the relevant cluster details
ambari-server/src/main/java/org/apache/ambari/server/serveraction/kerberos/KerberosServerAction.java