executor.submit(new Callable<Void>() {
@Override
public Void call() throws Exception {
ServerSet schedulerService = new ServerSetImpl(zkClient, SERVERSET_PATH);
final CountDownLatch schedulerReady = new CountDownLatch(1);
schedulerService.watch(new HostChangeMonitor<ServiceInstance>() {
@Override
public void onChange(ImmutableSet<ServiceInstance> hostSet) {
if (!hostSet.isEmpty()) {
schedulerReady.countDown();
}