nginx not working when deployed to Azure App Service

Question

I have a program consisting of Fast API, Celery, Flower and nginx written in Python. I use docker compose to build the images and deploy them to Azure App Service as a multi-container app.

My issue is that I cannot access Flower when deployed to Azure App Service. Locally, it works fine.

My docker-compose-build.yml which is used to build the images which are then pushed to ACR:

version: '3.4'

services:

  fast_api:
    container_name: fast_api
    build:
      context: .
      dockerfile: ./Dockerfile
    volumes:
      - .:/app
    ports:
      - 8080:8080
    depends_on:
      - redis

  celery_worker:
    container_name: celery_worker
    build: .
    command: celery -A app.celery.worker worker --loglevel=warning --pool=eventlet --concurrency=1000 -O fair 
    volumes:
      - .:/app
    environment:
      - CELERY_BROKER_URL=redis://redis:6379/0
      - CELERY_RESULT_BACKEND=redis://redis:6379/0
    depends_on:
      - fast_api
      - redis

  redis:
    container_name: redis
    image: redis:6-alpine 
    ports: 
      - 6379:6379

  flower:
    container_name: flower
    build: .
    command: celery -A app.celery.worker flower --port=5555 --url_prefix=flower
    ports:
      - 5555:5555
    environment:
      - CELERY_BROKER_URL=redis://redis:6379/0
      - CELERY_RESULT_BACKEND=redis://redis:6379/0
    depends_on:
      - fast_api
      - redis
      - celery_worker

  nginx:
    container_name: nginx
    build:
      context: .
      dockerfile: ./Dockerfile.nginx
    ports:
      - 80:80
    depends_on:
      - flower
      - fast_api

My docker-compose.yml which is used by Azure App Service:

version: '3.4'

services:
  fast_api:
    container_name: fast_api
    image: name.azurecr.io/name_fast_api:latest
    volumes:
      - ${WEBAPP_STORAGE_HOME}/app
    ports:
      - 8080:8080
    depends_on:
      - redis

  celery_worker:
    container_name: celery_worker
    image: name.azurecr.io/name_celery_worker:latest
    command: celery -A app.celery.worker worker --loglevel=warning --pool=eventlet --concurrency=1000 -O fair 
    volumes:
      - ${WEBAPP_STORAGE_HOME}/app
    environment:
      - CELERY_BROKER_URL=redis://redis:6379/0
      - CELERY_RESULT_BACKEND=redis://redis:6379/0
    depends_on:
      - fast_api
      - redis

  redis:
    container_name: redis
    image: name.azurecr.io/redis:6-alpine 
    ports: 
      - 6379:6379

  flower:
    container_name: flower
    image: name.azurecr.io/name_flower:latest
    command: celery -A app.celery.worker flower --port=5555 --url_prefix=flower
    ports:
      - 5555:5555
    environment:
      - CELERY_BROKER_URL=redis://redis:6379/0
      - CELERY_RESULT_BACKEND=redis://redis:6379/0
    depends_on:
      - fast_api
      - redis
      - celery_worker

  nginx:
    container_name: nginx
    image: name.azurecr.io/name_nginx:latest
    # volumes:
    #   - ${WEBAPP_STORAGE_HOME}/etc/nginx/nginx.conf #   Storage:/etc/nginx/nginx.conf #/etc/nginx/ #/usr/share/nginx/html ##/etc/nginx/nginx.conf
    ports:
      - 80:80
    depends_on:
      - flower
      - fast_api

Initially, in the docker-compose.yml, I pulled the image directly from Docker Hub, and then stored the nginx.conf file in Azure File Share which I mounted to the App Service. I had a suspicion that the nginx.conf file was not used by nginx. Therefore, I build a custom nginx image by creating Dockerfile.nginx where I copy in the nginx.conf file.

FROM nginx:stable
COPY nginx.conf /etc/nginx/nginx.conf

My nginx.conf file:

events {
  worker_connections  4096;  ## Default: 1024
}

http {

server {
    listen 80 default_server;
    #listen [::]:80;
    server_name _; #app-name.azurewebsites.net;

    location / {
        proxy_pass http://fast_api:8080/;
        proxy_set_header Host $host;
        proxy_redirect off;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "upgrade";
    }
        location /test {
        proxy_pass http://fast_api:8080/;
        proxy_set_header Host $host;
        proxy_redirect off;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "upgrade";
    }
    location /flower {
        proxy_pass http://flower:5555/flower;
        proxy_set_header Host $host;
        proxy_redirect off;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "upgrade";
    }
}
}

When I then go to https://app-name.azurewebsites.net/flower I get:

{ "detail": "Not Found" }

I can without problem access https://app-name.azurewebsites.net/docs and the API works perfectly.

Does anyone have an idea why I cannot access Flower when deployed to Azure?

Any help and ideas is appreciated as I have run out of things to try!

Answer 1

The issue has been solved. The issue was that all the docker services' ports were exposed externally, and that port 8080 was used by the fast_api service which might have conflicting with the fact that App Service is listening to port 8080 or 80 (https://docs.microsoft.com/en-us/azure/app-service/configure-custom-container?pivots=container-linux#configure-port-number) The solution was to only expose the nginx service's ports with the port parameter, and all other services should only by exposed internally with the expose parameter.