@Override
  public FaultDomainManager getFaultDomainManager(Config config, MetricsRegistry metricsRegistry) {
    return new SingleFaultDomainManager();
  }
Produces a simple placeholder {@link FaultDomainManager}. See {@link SingleFaultDomainManager}.
samza-core/src/main/java/org/apache/samza/clustermanager/SingleFaultDomainManagerFactory.java