Gunicorn stuck on docker when run is executed with flask application

Question

I'm running a container app_container built, exposing port 8000 and with its entry point being ENTRYPOINT ["/usr/local/bin/gunicorn", "web_interface:app", "-w 4", "-t 90", "--log-level=info", "-b 127.0.0.1:8000", "--reload"].

My container stops if I try and run the app locally but  if I run it with docker run --link postgres_db_container --name foo app_container, the gunicorn command runs to the app.

Locally the container stops here:

[2017-06-19 16:01:16 +0000] [1] [INFO] Starting gunicorn 19.7.1
[2017-06-19 16:01:16 +0000] [1] [INFO] Listening at: http://127.0.0.1:8000
[2017-06-19 16:01:16 +0000] [1] [INFO] Using worker: sync
[2017-06-19 16:01:16 +0000] [8] [INFO] Booting worker with pid: 8
[2017-06-19 16:01:16 +0000] [10] [INFO] Booting worker with pid: 10
[2017-06-19 16:01:16 +0000] [11] [INFO] Booting worker with pid: 11
[2017-06-19 16:01:16 +0000] [13] [INFO] Booting worker with pid: 13

If I interrupt the process it shows a test print message

^C[2017-06-19 16:09:27 +0000] [1] [INFO] Handling signal: int
[2017-06-19 16:09:27 +0000] [10] [INFO] Worker exiting (pid: 10)
[2017-06-19 16:09:27 +0000] [11] [INFO] Worker exiting (pid: 11)
[2017-06-19 16:09:27 +0000] [8] [INFO] Worker exiting (pid: 8)
---- Generate Mapping ----
---- Preparing Databases ----

I think Gunicorn is stuck on some process.

Am I doing anything wrong here? There isn't even any error for me to troubleshoot them.

Comments

Hi,

Im facing the exact same issue. Were you able to resolve it?

Thanks.

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Did you try the below-given solution?

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Yes I did, but same issue. I dont think it is the port mapping issue.

When I run my docker container, its boots up and gets stuck at:

[2020-07-09 11:07:45 +0000] [1] [INFO] Starting gunicorn 19.10.0

[2020-07-09 11:07:45 +0000] [1] [INFO] Listening at: http://0.0.0.0:5002 (1)

[2020-07-09 11:07:45 +0000] [1] [INFO] Using worker: sync

[2020-07-09 11:07:45 +0000] [8] [INFO] Booting worker with pid: 8

This is the same even if I increase timeout.
But once I enter Ctrl+C to exit, it prints the output

^C[2020-07-09 11:08:51 +0000] [1] [INFO] Handling signal: int
checkpoint1
checkpoint2
checkpoint3
checkpoint4

Port mapping are also correct.
Why is this happening? I even tried with different versions of gunicorn and python. But still the same.My docker cmd:

CMD ["gunicorn","-w","1","--timeout","1200","-b","0.0.0.0:5002","api:app"]

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Try with detach mode and check with the docker ps command. Is it in a running state or not?

Answer 1

Here's something that you could try:

• Check your port is mapping to you localhost so that it can access the container

  docker run -p 8000:8000 (rest of the command)

• Also, change your listening port to "-b 127.0.0.1:8000" from "-b 0.0.0.0:8000". this is kinda requirement for docker to map ports. In docker ps you'll see 0.0.0.0:8000->8000

Now, check your localhost:8000 in your web browser to see if the app is working properly.