ppenelon opened a new pull request, #40677:
URL: https://github.com/apache/airflow/pull/40677
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Hi,
I recently had a huge pain point with Airflow running on ECS via the
official airflow Docker image (`apache/airflow:2.9.2`).
For the configuration I have a scheduler (4 vCPU, 8 Gib), some workers (4
vCPU, 8 Gib) and a webserver (2 vCPU, 4 Gib).
Every containers are sharing the same environment variables to apply the
same configuration anywhere.
The problem was that at some point, the scheduler were non-stop crashing
with the following error:
```
File
""/home/airflow/.local/lib/python3.12/site-packages/airflow/jobs/scheduler_job_runner.py"",
line 1738, in _find_zombies
self.job.executor.send_callback(request)
File
""/home/airflow/.local/lib/python3.12/site-packages/airflow/executors/base_executor.py"",
line 499, in send_callback
self.callback_sink.send(request)
File
""/home/airflow/.local/lib/python3.12/site-packages/airflow/callbacks/pipe_callback_sink.py"",
line 47, in send
self._get_sink_pipe().send(callback)
File ""/usr/local/lib/python3.12/multiprocessing/connection.py"", line 206,
in send
self._send_bytes(_ForkingPickler.dumps(obj))
File ""/usr/local/lib/python3.12/multiprocessing/connection.py"", line 427,
in _send_bytes
self._send(header + buf)
File ""/usr/local/lib/python3.12/multiprocessing/connection.py"", line 384,
in _send
n = write(self._handle, buf)
^^^^^^^^^^^^^^^^^^^^^^^^
BlockingIOError: [Errno 11] Resource temporarily unavailable
```
The first attempt was to increase the maximum file descriptor for the
`airflow` user from 1000 (default) to 65535 (root limit) which works some time
but after some days the problem came back.
After many (many) unsuccessful attempts, I saw an article speaking about the
gevent patching when using gevent on the webserver (which was my case).
As the `_AIRFLOW_PATCH_GEVENT` environment variable was set on every
container which means that the gevent patching was applied on the webserver but
**also on the scheduler**.
I'm not a Python expert but the conclusion was that the gevent patching was
affecting the `multiprocessing` module via the duplex sockets.
As it was a painful problem to solve I'm proposing this documentation
upgrade to warn anyone to apply this setup.
I'm not sure if it's the right way to do it but feel free to
take/modify/close this merge request the way you want, as it can already serve
anyone searching for this error via Google.
Thanks
---
**^ Add meaningful description above**
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