@Override
  public Set<Resource> getResources(Request request, Predicate predicate)
      throws SystemException, UnsupportedPropertyException,
    NoSuchResourceException, NoSuchParentResourceException {

    final Set<StackServiceRequest> requests = new HashSet<>();

    if (predicate == null) {
      requests.add(getRequest(Collections.emptyMap()));
    } else {
      for (Map<String, Object> propertyMap : getPropertyMaps(predicate)) {
        requests.add(getRequest(propertyMap));
      }
    }

    Set<String> requestedIds = getRequestPropertyIds(request, predicate);

    Set<StackServiceResponse> responses = getResources(new Command<Set<StackServiceResponse>>() {
      @Override
      public Set<StackServiceResponse> invoke() throws AmbariException {
        return getManagementController().getStackServices(requests);
      }
    });

    Set<Resource> resources = new HashSet<>();

    for (StackServiceResponse response : responses) {
      Resource resource = createResource(response, requestedIds);

      resources.add(resource);
    }

    return resources;
  }
KerberosServiceDescriptorFactory used to create KerberosServiceDescriptor instances
ambari-server/src/main/java/org/apache/ambari/server/controller/internal/StackServiceResourceProvider.java