server_def.set_task_index(0);
  std::unique_ptr<tensorflow::ServerInterface> w0;
  ASSERT_TRUE(
      factory->NewServer(server_def, ServerFactory::Options(), &w0).ok());
  ASSERT_TRUE(w0->Start().ok());
  server_def.set_task_index(1);
  std::unique_ptr<tensorflow::ServerInterface> w1;
  ASSERT_TRUE(
      factory->NewServer(server_def, ServerFactory::Options(), &w1).ok());
  ASSERT_TRUE(w1->Start().ok());