confFileObj.setMapredMapTasks(numMapTasks);
confFileObj.setMapredReduceTasks(numReduceTasks);
File confFile = new File(pathExecDir + FILENAME_CONF);
try {
FileWriter writer = new FileWriter(confFile);
writer.write(confFileObj.toXml());
writer.close();
} catch (IOException e) {
return new Failure("Failure writing conf file: " + e.getMessage());
}