<p>What does this error mean? I have a simple airflow setup where I ran the <a href="https://airflow.apache.org/docs/helm-chart/stable/index.html" rel="nofollow noreferrer">airflow helm chart</a> on a local kind/kubernetes cluster with the <code>CeleryKubernetesExecutor</code></p>
<pre><code>│ scheduler [2022-05-25 06:55:40,086] {dagrun.py:648} WARNING - Failed to get task '&lt;TaskInstance: tutorial.generated-task-13 manual__2022 │
│ scheduler [2022-05-25 06:55:40,086] {dagrun.py:648} WARNING - Failed to get task '&lt;TaskInstance: tutorial.generated-task-17 manual__2022 │
│ scheduler [2022-05-25 06:55:40,207] {scheduler_job.py:1347} WARNING - Failing (6) jobs without heartbeat after 2022-05-25 06:50:40.19719 │
│ scheduler [2022-05-25 06:55:40,207] {scheduler_job.py:1355} ERROR - Detected zombie job: {'full_filepath': '/opt/airflow/dags/repo/dags/ │
│ scheduler [2022-05-25 06:55:40,208] {scheduler_job.py:753} ERROR - Exception when executing SchedulerJob._run_scheduler_loop             │
│ scheduler Traceback (most recent call last):                                                                                             │
│ scheduler   File &quot;/home/airflow/.local/lib/python3.7/site-packages/airflow/jobs/scheduler_job.py&quot;, line 736, in _execute                 │
│ scheduler     self._run_scheduler_loop()                                                                                                 │
│ scheduler   File &quot;/home/airflow/.local/lib/python3.7/site-packages/airflow/jobs/scheduler_job.py&quot;, line 836, in _run_scheduler_loop      │
│ scheduler     next_event = timers.run(blocking=False)                                                                                    │
│ scheduler   File &quot;/usr/local/lib/python3.7/sched.py&quot;, line 151, in run                                                                   │
│ scheduler     action(*argument, **kwargs)                                                                                                │
│ scheduler   File &quot;/home/airflow/.local/lib/python3.7/site-packages/airflow/utils/event_scheduler.py&quot;, line 36, in repeat                 │
│ scheduler     action(*args, **kwargs)                                                                                                    │
│ scheduler   File &quot;/home/airflow/.local/lib/python3.7/site-packages/airflow/utils/session.py&quot;, line 71, in wrapper                        │
│ scheduler     return func(*args, session=session, **kwargs)                                                                              │
│ scheduler   File &quot;/home/airflow/.local/lib/python3.7/site-packages/airflow/jobs/scheduler_job.py&quot;, line 1356, in _find_zombies           │
│ scheduler     self.executor.send_callback(request)                                                                                       │
│ scheduler AttributeError: 'CeleryKubernetesExecutor' object has no attribute 'send_callback'                                             │
│ scheduler [2022-05-25 06:55:40,218] {kubernetes_executor.py:807} INFO - Shutting down Kubernetes executor                                │
│ scheduler [2022-05-25 06:55:41,237] {process_utils.py:129} INFO - Sending Signals.SIGTERM to group 64. PIDs of all processes in the grou │
│ scheduler [2022-05-25 06:55:41,237] {process_utils.py:80} INFO - Sending the signal Signals.SIGTERM to group 64                          │
│ scheduler [2022-05-25 06:55:41,409] {process_utils.py:75} INFO - Process psutil.Process(pid=64, status='terminated', exitcode=0, started │
│ scheduler [2022-05-25 06:55:41,410] {scheduler_job.py:765} INFO - Exited execute loop                                                    │
│ scheduler Traceback (most recent call last):                                                                                             │
│ scheduler   File &quot;/home/airflow/.local/bin/airflow&quot;, line 8, in &lt;module&gt;                                                                 │
│ scheduler     sys.exit(main())                                                                                                           │
│ scheduler   File &quot;/home/airflow/.local/lib/python3.7/site-packages/airflow/__main__.py&quot;, line 38, in main                                │
│ scheduler     args.func(args)                                                                                                            │
│ scheduler   File &quot;/home/airflow/.local/lib/python3.7/site-packages/airflow/cli/cli_parser.py&quot;, line 51, in command                       │
│ scheduler     return func(*args, **kwargs)                                                                                               │
│ scheduler   File &quot;/home/airflow/.local/lib/python3.7/site-packages/airflow/utils/cli.py&quot;, line 99, in wrapper                            │
│ scheduler     return f(*args, **kwargs)                                                                                                  │
│ scheduler   File &quot;/home/airflow/.local/lib/python3.7/site-packages/airflow/cli/commands/scheduler_command.py&quot;, line 75, in scheduler     │
│ scheduler     _run_scheduler_job(args=args)                                                                                              │
│ scheduler   File &quot;/home/airflow/.local/lib/python3.7/site-packages/airflow/cli/commands/scheduler_command.py&quot;, line 46, in _run_schedule │
│ scheduler     job.run()                                                                                                                  │
│ scheduler   File &quot;/home/airflow/.local/lib/python3.7/site-packages/airflow/jobs/base_job.py&quot;, line 244, in run                           │
│ scheduler     self._execute()                                                                                                            │
│ scheduler   File &quot;/home/airflow/.local/lib/python3.7/site-packages/airflow/jobs/scheduler_job.py&quot;, line 736, in _execute                 │
│ scheduler     self._run_scheduler_loop()                                                                                                 │
│ scheduler   File &quot;/home/airflow/.local/lib/python3.7/site-packages/airflow/jobs/scheduler_job.py&quot;, line 836, in _run_scheduler_loop      │
│ scheduler     next_event = timers.run(blocking=False)                                                                                    │
│ scheduler   File &quot;/usr/local/lib/python3.7/sched.py&quot;, line 151, in run                                                                   │
│ scheduler     action(*argument, **kwargs)                                                                                                │
│ scheduler   File &quot;/home/airflow/.local/lib/python3.7/site-packages/airflow/utils/event_scheduler.py&quot;, line 36, in repeat                 │
│ scheduler     action(*args, **kwargs)                                                                                                    │
│ scheduler   File &quot;/home/airflow/.local/lib/python3.7/site-packages/airflow/utils/session.py&quot;, line 71, in wrapper                        │
│ scheduler     return func(*args, session=session, **kwargs)                                                                              │
│ scheduler   File &quot;/home/airflow/.local/lib/python3.7/site-packages/airflow/jobs/scheduler_job.py&quot;, line 1356, in _find_zombies           │
│ scheduler     self.executor.send_callback(request)                                                                                       │
│ scheduler AttributeError: 'CeleryKubernetesExecutor' object has no attribute 'send_callback'                                             │
</code></pre>
<p>Isit erroring because I updated my dag definition and some tasks are now zombie/invalid? I suspect this is causing a crash tho &quot;<em><strong>AttributeError: 'CeleryKubernetesExecutor' object has no attribute 'send_callback'</strong></em>&quot;, but whats wrong?</p>

<p>Seem to be an airflow <a href="https://github.com/apache/airflow/issues/23610" rel="nofollow noreferrer">issue</a> in version 2.3.0</p>
<p>It is fixed in <a href="https://airflow.apache.org/docs/apache-airflow/2.3.1/release_notes.html#airflow-2-3-1-2022-05-25" rel="nofollow noreferrer">2.3.1</a></p>
