Deploying Docker Container Registry on Azure App Service Issue

Question

I am unable to rum Docker Container Registry on the Azure App service. I have a flask app and the following is the Dockerfile of it:-

FROM python:3.8-slim-buster
WORKDIR /usr/src/app
COPY requirements.txt .
RUN pip install --no-cache-dir -r requirements.txt

# copy project
WORKDIR /usr/src/app
COPY . /usr/src/app/

# expose port 80
EXPOSE 80
CMD ["gunicorn", "-w", "4", "-b", "0.0.0.0:80", "app:app"]

I have deployed the docker image on the Container Registry. I have also set WEBSITES_PORT to 80 under App Service -> Application Settings. Even after doing that, I get the following error:-

  ERROR - Container XYZ didn't respond to HTTP pings on port: 80, failing site start.

I have tried running it locally and it works fine. But, it just does not seem to work on the Azure App service. Any help is highly appreciated.

Answer 1

I don't see an issue in the code you posted but to verify, here is a configuration for a Flask app with a Gunicorn server that works on a containerized Azure App Service:

app.py

from flask import Flask
    
app = Flask(__name__)
    
@app.route("/")
def hello_world():
    return "<p>Hello World!</p>"

Dockerfile

FROM python:3.8-slim-buster
ADD app.py app.py
ADD requirements.txt requirements.txt
RUN pip install --upgrade pip
RUN python3 -m pip install -r requirements.txt

EXPOSE 80

CMD ["gunicorn", "--bind=0.0.0.0:80", "app:app"]

requirements.txt

flask
gunicorn

I assume you selected "Docker Container" when you created the Azure App Service?

And then simply chose your image?