Airflow DAG 직렬화 : TypeError : 'V1Pod'유형의 개체가 JSON 직렬화 가능하지 않습니다.

"KubernetesExecutor를 사용할 때 Airflow는 작업별로 시스템 기본값을 재정의하는 기능을 제공합니다.이 기능을 활용하기 위해 Kubernetes V1pod개체를 만들고 원하는 재정의를 채울 수 있습니다."

다음 연산자로 DAG를 트리거하려고합니다 (공식 핵심 문서의 예).

...
volume_task = PythonOperator(
            task_id="task_with_volume",
            python_callable=test_volume_mount,
            executor_config={
                "pod_override": k8s.V1Pod(
                    spec=k8s.V1PodSpec(
                        containers=[
                            k8s.V1Container(
                                name="base",
                                volume_mounts=[
                                    k8s.V1VolumeMount(
                                        mount_path="/foo/", name="example-kubernetes-test-volume"
                                    )
                                ],
                            )
                        ],
                        volumes=[
                            k8s.V1Volume(
                                name="example-kubernetes-test-volume",
                                host_path=k8s.V1HostPathVolumeSource(path="/tmp/"),
                            )
                        ],
                    )
                ),
            },
        )
...

UI에서 내 DAG를 클릭하면 다음 오류가 발생합니다.

                          ____/ (  (    )   )  \___
                         /( (  (  )   _    ))  )   )\
                       ((     (   )(    )  )   (   )  )
                     ((/  ( _(   )   (   _) ) (  () )  )
                    ( (  ( (_)   ((    (   )  .((_ ) .  )_
                   ( (  )    (      (  )    )   ) . ) (   )
                  (  (   (  (   ) (  _  ( _) ).  ) . ) ) ( )
                  ( (  (   ) (  )   (  ))     ) _)(   )  )  )
                 ( (  ( \ ) (    (_  ( ) ( )  )   ) )  )) ( )
                  (  (   (  (   (_ ( ) ( _    )  ) (  )  )   )
                 ( (  ( (  (  )     (_  )  ) )  _)   ) _( ( )
                  ((  (   )(    (     _    )   _) _(_ (  (_ )
                   (_((__(_(__(( ( ( |  ) ) ) )_))__))_)___)
                   ((__)        \\||lll|l||///          \_))
                            (   /(/ (  )  ) )\   )
                          (    ( ( ( | | ) ) )\   )
                           (   /(| / ( )) ) ) )) )
                         (     ( ((((_(|)_)))))     )
                          (      ||\(|(|)|/||     )
                        (        |(||(||)||||        )
                          (     //|/l|||)|\\ \     )
                        (/ / //  /|//||||\\  \ \  \ _)
-------------------------------------------------------------------------------
Node: 9c9de21b5ea0
-------------------------------------------------------------------------------
Traceback (most recent call last):
  File "/opt/python3.6/lib/python3.6/site-packages/flask/app.py", line 2447, in wsgi_app
    response = self.full_dispatch_request()
  File "/opt/python3.6/lib/python3.6/site-packages/flask/app.py", line 1952, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/opt/python3.6/lib/python3.6/site-packages/flask/app.py", line 1821, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/opt/python3.6/lib/python3.6/site-packages/flask/_compat.py", line 39, in reraise
    raise value
  File "/opt/python3.6/lib/python3.6/site-packages/flask/app.py", line 1950, in full_dispatch_request
    rv = self.dispatch_request()
  File "/opt/python3.6/lib/python3.6/site-packages/flask/app.py", line 1936, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/opt/python3.6/lib/python3.6/site-packages/flask_admin/base.py", line 69, in inner
    return self._run_view(f, *args, **kwargs)
  File "/opt/python3.6/lib/python3.6/site-packages/flask_admin/base.py", line 368, in _run_view
    return fn(self, *args, **kwargs)
  File "/opt/python3.6/lib/python3.6/site-packages/flask_login/utils.py", line 258, in decorated_view
    return func(*args, **kwargs)
  File "/usr/local/lib/airflow/airflow/www/utils.py", line 386, in view_func
    return f(*args, **kwargs)
  File "/usr/local/lib/airflow/airflow/www/utils.py", line 292, in wrapper
    return f(*args, **kwargs)
  File "/usr/local/lib/airflow/airflow/utils/db.py", line 74, in wrapper
    return func(*args, **kwargs)
  File "/usr/local/lib/airflow/airflow/www/views.py", line 1706, in tree
    show_external_logs=bool(external_logs))
  File "/usr/local/lib/airflow/airflow/www/views.py", line 425, in render
    return super(AirflowViewMixin, self).render(template, **kwargs)
  File "/opt/python3.6/lib/python3.6/site-packages/flask_admin/base.py", line 308, in render
    return render_template(template, **kwargs)
  File "/opt/python3.6/lib/python3.6/site-packages/flask/templating.py", line 140, in render_template
    ctx.app,
  File "/opt/python3.6/lib/python3.6/site-packages/flask/templating.py", line 120, in _render
    rv = template.render(context)
  File "/opt/python3.6/lib/python3.6/site-packages/jinja2/environment.py", line 1090, in render
    self.environment.handle_exception()
  File "/opt/python3.6/lib/python3.6/site-packages/jinja2/environment.py", line 832, in handle_exception
    reraise(*rewrite_traceback_stack(source=source))
  File "/opt/python3.6/lib/python3.6/site-packages/jinja2/_compat.py", line 28, in reraise
    raise value.with_traceback(tb)
  File "/usr/local/lib/airflow/airflow/www/templates/airflow/tree.html", line 20, in top-level template code
    {% extends "airflow/dag.html" %}
  File "/usr/local/lib/airflow/airflow/www/templates/airflow/dag.html", line 21, in top-level template code
    {% import 'admin/lib.html' as lib with context %}
  File "/usr/local/lib/airflow/airflow/www/templates/airflow/master.html", line 20, in top-level template code
    {% extends "admin/master.html" %}
  File "/usr/local/lib/airflow/airflow/www/templates/admin/master.html", line 20, in top-level template code
    {% extends 'admin/base.html' %}
  File "/opt/python3.6/lib/python3.6/site-packages/flask_admin/templates/bootstrap3/admin/base.html", line 95, in top-level template code
    {% block tail %}
  File "/usr/local/lib/airflow/airflow/www/templates/airflow/tree.html", line 85, in block "tail"
    var data = {{ data|tojson }};
  File "/opt/python3.6/lib/python3.6/site-packages/flask/json/__init__.py", line 376, in tojson_filter
    return Markup(htmlsafe_dumps(obj, **kwargs))
  File "/opt/python3.6/lib/python3.6/site-packages/flask/json/__init__.py", line 290, in htmlsafe_dumps
    dumps(obj, **kwargs)
  File "/opt/python3.6/lib/python3.6/site-packages/flask/json/__init__.py", line 211, in dumps
    rv = _json.dumps(obj, **kwargs)
  File "/opt/python3.6/lib/python3.6/json/__init__.py", line 238, in dumps
    **kw).encode(obj)
  File "/opt/python3.6/lib/python3.6/json/encoder.py", line 199, in encode
    chunks = self.iterencode(o, _one_shot=True)
  File "/opt/python3.6/lib/python3.6/json/encoder.py", line 257, in iterencode
    return _iterencode(o, 0)
  File "/opt/python3.6/lib/python3.6/site-packages/flask/json/__init__.py", line 100, in default
    return _json.JSONEncoder.default(self, o)
  File "/opt/python3.6/lib/python3.6/json/encoder.py", line 180, in default
    o.__class__.__name__)
TypeError: Object of type 'V1Pod' is not JSON serializable

무슨 일이 일어나고 있는지 그리고 어떻게 문제를 해결할 수 있는지 알려 주실 수 있습니까? 감사