CRITICAL WORKER TIMEOUT when running Flask app #1801
Comments
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The error is not expected, but there is nothing from your example that shows why it happens. Tell us more about your environment.
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I've just reproduced the problem on a completely fresh setup, here are the steps: mkdir gunicorn
cd gunicorn/
pipenv --python 3.6
pipenv install flask
pipenv install gunicorn
vim hello.py
pipenv shell
gunicorn -b 0.0.0.0:5000 --log-level=debug helloThe |
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@bigunyak I think it's because of the default timeout, your worker has been silent for 30s. http://docs.gunicorn.org/en/stable/settings.html#timeout From your log, |
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I'm seeing the same thing: workers are timing out even when serving no requests, with sync worker. Try use Gevent worker could solve this. |
Exactly, that was my original question: if it's an expected behavior why critical error then? |
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I'm thinking info level might be a little bit better. |
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I had the same with MSYS2 on Win10 but finally could solved. in notify() of ...\gunicorn\workers\workertmp.py, os.fchmod is used originally. But it does not work in MSYS. Instead of os.fchmod, I used os.utime. The code is followed. I think it could work for all platform. |
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@berkerpeksag I wouldn't expect that the worker exit because no requests happen. This error should only happen if the worker has been kept busy for a time > to the timeout. So the error is critical. Imo we should improve the documentation to provide more use cases and responses to such errors. If the error still happen when the worker is not kept busy then there is something else happening and we have probably a bug. |
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[EDIT]
We're going to try gunicorn gevent to see if we'are able to get our app back online. |
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Using gunicorn with gevent didn't fixed the bug. |
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any update on this issue ? |
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It looks like @neocolor identified a real bug under MSYS. It might deserve a separate issue. @bigunyak what platform are you running under? I have tried to reproduce with the simple example and I cannot do it following exactly the steps outlined above. This agrees with my experience running multiple applications in production on multiple frameworks. The worker notification system has not changed recently, to my knowledge. My platform is Python 3.7 on MacOS 10.13.6, but I run Gunicorn in production with sync workers for several applications on Python 2.7 and 3.6.5 and only see worker timeouts when there are legitimately long requests that block the workers. For @Tberdy: what happens if you try to set |
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See also #1388 for Docker related tmpfs issues. |
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i have this issue to. |
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I have this issue too, gunicorn sync was working perfectly well until yesternight, ut started reporting, workers timeout [CRITICAL] using gevent seems to solve my issue, but I'd really want to know why this happened . |
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@timoj58 @cjmash can you provides more detail about the issue ? How are you running gunicorn (in a vm?, options ...), which fileystem, OS? ANthing that could help to reproduce would be very helpful :) |
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@benoitc I am running gunicorn to start my Django project on kubernetes my gunicorn arguments are --bind=$port --workers=7 --timeout=1200 --log-level=debug --access-logfile - error-logfile -" the errors i get from the logs |
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I struggled a bit to reproduce the problem this time but it's still there in the latest gunicorn version 19.9.0. As before to test it I was just hitting http://0.0.0.0:5000/ in Chromium.
{
"_meta": {
"hash": {
"sha256": "81cb5d5f0b11719d8d9c5ec9cc683fdcf959c652fda256d5552a82d0f459a99c"
},
"pipfile-spec": 6,
"requires": {
"python_version": "3.6"
},
"sources": [
{
"name": "pypi",
"url": "https://pypi.org/simple",
"verify_ssl": true
}
]
},
"default": {
"click": {
"hashes": [
"sha256:29f99fc6125fbc931b758dc053b3114e55c77a6e4c6c3a2674a2dc986016381d",
"sha256:f15516df478d5a56180fbf80e68f206010e6d160fc39fa508b65e035fd75130b"
],
"version": "==6.7"
},
"flask": {
"hashes": [
"sha256:2271c0070dbcb5275fad4a82e29f23ab92682dc45f9dfbc22c02ba9b9322ce48",
"sha256:a080b744b7e345ccfcbc77954861cb05b3c63786e93f2b3875e0913d44b43f05"
],
"index": "pypi",
"version": "==1.0.2"
},
"gunicorn": {
"hashes": [
"sha256:aa8e0b40b4157b36a5df5e599f45c9c76d6af43845ba3b3b0efe2c70473c2471",
"sha256:fa2662097c66f920f53f70621c6c58ca4a3c4d3434205e608e121b5b3b71f4f3"
],
"index": "pypi",
"version": "==19.9.0"
},
"itsdangerous": {
"hashes": [
"sha256:cbb3fcf8d3e33df861709ecaf89d9e6629cff0a217bc2848f1b41cd30d360519"
],
"version": "==0.24"
},
"jinja2": {
"hashes": [
"sha256:74c935a1b8bb9a3947c50a54766a969d4846290e1e788ea44c1392163723c3bd",
"sha256:f84be1bb0040caca4cea721fcbbbbd61f9be9464ca236387158b0feea01914a4"
],
"version": "==2.10"
},
"markupsafe": {
"hashes": [
"sha256:a6be69091dac236ea9c6bc7d012beab42010fa914c459791d627dad4910eb665"
],
"version": "==1.0"
},
"werkzeug": {
"hashes": [
"sha256:c3fd7a7d41976d9f44db327260e263132466836cef6f91512889ed60ad26557c",
"sha256:d5da73735293558eb1651ee2fddc4d0dedcfa06538b8813a2e20011583c9e49b"
],
"version": "==0.14.1"
}
},
"develop": {}
} |
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Just FYI, I'm also seeing this failure very regularly with:
I just have a wsgi.py that has Let me know if there is anything you want me to try/experiment or if there are specifics in the logs you want me to check. I'm running flask on a GCP VM. |
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sorry for late reply. I am running it as gunicorn --log-file=/home/ubuntu/log/gunicorn.log predictor_api:app -b localhost:5000 & i did use the gevent setting etc, but i have changed my design of what i required this for in order to work around issue, hence the basic setting above (which also failed but this is to be expected given no gevent) Python version 3.6 flask version 1.0.2 I did change the nginx timeouts as well incase this may have caused it. |
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Facing the same problem with gunicorn server gunicorn ApplicationServer:app -b 0.0.0.0:6001 -w 8 --threads 4 --backlog 2048 \--timeout 120 --graceful-timeout 60 --access-logfile logs/access.log \--error-logfile logs/error.log --log-level=infoFlask==0.12.1 when i start server with above command, my system got freezing for some time and worker pids are keeping on booting , though i kept timeout 120 sec, and the server is not accepting single request. |
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Any update on this issue ? I have same issue
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Wondering whether anyone has successfully reproduced this in a Docker image? |
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Also seeing this when trying to implement datadog's ddtrace-run worker on an existing application starting with gunicorn -k gevent --threads 4. Funny trace of a SystemExit I've never seen before too... |
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I am able to resolve this issue by matching the number of workers and number of threads. I had set Once I changed This is how it looks now |
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I encountered this issue running Django with a single Docker container on AWS Elastic Beanstalk. I resolved the issue by fixing my security groups to ensure my EC2 instance could talk to my RDS instance. I recognize this may not be the solution for 99% of folks on this issue, but I'm leaving this note to help others avoid wasting hours falling down this rabbit hole. |
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I had a similar issue to this. Turns out I had an error in my entrypoint to the application. From debugging it seemed that I was essentially launching a flask app from gunicorn, who's workers subsequently enter an infinite connection loop which times out every 30s. I'm sure that this doesn't affect all users above, but may well affect some. In my Whereas I should've had - Essentially, you don't want to call I couldn't find a reference to this in the gunicorn docs, but could imagine it being a common error case, so maybe some warning is necessary. |
Increased Gunicorn workers as per critical timeout issue: benoitc/gunicorn#1801
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This is still occuring. Adding |
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Is this bug still not fixed? I am observing this exact behavior. Gunicorn starts like this in systemd: Worker process constantly times out and restarts: app.py is a trival Flask app. Is this issue closed as Don't Fix? |
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I was also having the same issue But after Debugging Im able to find that while gunicorn starts Django App one of the dependency was taking longer than the expected time , ( In my case external DB connection ) which make the When I resolved the connection issue , timeout issue also resolved ... |
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This would not my case. I tested with “Hello, World” type of app, with no dependencies. So I am still puzzled by this, but it seems it’s not possible to have Gunicorn with long running thread. Worker process restarts and therefore kill the long running thread.
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@leonbrag |
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Is there a reference architecture/design that shows a proper way to set up Gunicorn flask app with long (permanent) worker thread ?
If this is not a bug, then it’s seems an artifact or a limitation of the Gunicorn architecture/design.
Why would not sync worker run forever and accept clients connections. Such worker would close socket as needed, yet continue to run without exIting (and therefor worker thread continue to run).
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@leonbrag The problem discussed in this thread happens in dev environment and the easiest solution is either to add more sync workers or use threaded workers. If you want to avoid this issue in production setup, you can use gevent workers, or you can put an nginx infront of gunicorn. This is a good reading. |
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you can check the design page from the documentation. Async workers is one
way to run long tasks.
On Sat 8 Aug 2020 at 18:00 leonbrag ***@***.***> wrote:
Is there a reference architecture/design that shows a proper way to set up
Gunicorn flask app with long (permanent) worker thread ?
If this is not a bug, then it’s seems an artifact or a limitation of the
Gunicorn architecture/design.
Why would not sync worker run forever and accept clients connections. Such
worker would close socket as needed, yet continue to run without exIting
(and therefor worker thread continue to run).
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web: gunicorn --workers=3 app:app --timeout 200 --log-file - I fixed my problem by incresing the --timeout |
Oh, thanks a lot Randall, I forgot to add BTW will 64 Mb be enough for gunicorn cache? |
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gunicorn app:app --timeout 1000 Worked for me... I prefer timeout one. |
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Strange, I added To make sure
The params are next: PS: I am using PyPy @attajutt timeout is nice but you are risking that gunicorn master process will detect hangup in your worker process only after 1000 seconds, and you will miss a lot of requests. Also it will be hard to detect it if only one of several workers will hangup. I would not do 1000 at least. |
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@ivictbor thanks for lmk. 1000 is for reference. Nevertheless, I got the app rolling once Its loaded It is running perfectly fine. |
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I got this error problem too and after several times, I found that the problem is probably caused :
If you deploy your app in cloud like GAE, that will not surface anything hint error. If raised 502 bad gateway;
complete sulotion explained in here : https://www.datadoghq.com/blog/nginx-502-bad-gateway-errors-gunicorn/ hope that can fix anyone got error in [CRITICAL] WORKER TIMEOUT |
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Adding another possibility for those who find this thread... This can also be caused by having docker imposed resource constrains that are too low for you web application. For example I had the following constraints: and these were evidently too low for |
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For gunicorn this resources are perfectly fine. But you indeed need to
plane for the number of workers and the resources needed for your
application. 128M and 0.25cpu seems really low for a web application
written in Python.... generally speaking you need at least 1 core /vcpu and
512MB of RAM as a bare minimum.
On Fri 26 Mar 2021 at 02:14, Colton Hicks ***@***.***> wrote:
Adding another possibility for those who find this thread...
This can also be caused by having docker imposed resource constrains that
are too low for you web application. For example I had the following
constraints:
services:
web_app:
image: blah-blah
deploy:
resources:
limits:
cpus: "0.25"
memory: 128M
and these were evidently too low for gunicorn so I constantly got the [CRITICAL]
WORKER TIMEOUT error until I removed the constraints.
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--timeout=1000 worked form me. Issue was a low-cpu resourced GCP machine. It worked fine on my local machine with the default timeout. |
You're great. It was for me the solution. Thanks very much. |
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gunicorn app:app --timeout 3000 Worked for me ✌️ |
and others
It seems there have been already several reports related to
[CRITICAL] WORKER TIMEOUTerror but it just keeps popping up. Here is my issue.I'm running this Flask hello world application.
The gunicorn command is this one:
And this is the console output:
Can you please clearly explain why do I get the error and if it's expected in this example? How do I fix it or if it's an expected behavior why critical error then?
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