this.joinThreadControl = new JoinThreadControl(threadPool);
transportService.registerHandler(DISCOVERY_REJOIN_ACTION_NAME, new RejoinClusterRequestHandler());
dynamicSettings.addDynamicSetting(ElectMasterService.DISCOVERY_ZEN_MINIMUM_MASTER_NODES, new Validator() {
@Override
public String validate(String setting, String value) {
int intValue;
try {
intValue = Integer.parseInt(value);