503 connect() failed (111: Connection refused) while connecting to upstream

Questions

I set up flask + jwilder with basic auth and got success code… Then i set up gunicorn + jwilder, but got error,

My error :

[error] 52#52: *1 connect() failed (111: Connection refused) while connecting to upstream, client: 172.20.0.1, server: my.local, request: "GET / HTTP/1.1", upstream: "http://172.20.0.2:8000/", host: "my.local"

My working code :

• Docker-compose.py

version: '3.7'
services:

  web:
    build: ./myapp
    restart: always
    networks:
      - proxynet
    environment:
      - VIRTUAL_HOST=my.local
      - VIRTUAL_PORT=5000
    expose:
      - 5000

  nginx-proxy:
    container_name: nginx-proxy
    restart: always
    image: jwilder/nginx-proxy:alpine
    ports:
      - "80:80"
      - "443:443"
    volumes:
      - ./nginx-proxy/secrets/htpasswd:/etc/nginx/htpasswd
      - ./nginx-proxy/conf.d:/etc/nginx/conf.d
      - ./nginx-proxy/vhost.d:/etc/nginx/vhost.d
      - ./nginx-proxy/html:/usr/share/nginx/html
      - ./nginx-proxy/certs:/etc/nginx/certs
      - /var/run/docker.sock:/tmp/docker.sock:ro
    networks: 
      - proxynet

networks:
  proxynet:
    external: true

• Dockerfile.py

FROM python:3.4-alpine
ADD . /code
WORKDIR /code
RUN pip install -r requirements
CMD ["python", "app.py"]

My app.py

from flask import Flask
app = Flask(__name__)

@app.route('/')
def hello_world():
    return 'Hello world!'

if __name__ == '__main__':
    app.run(host='0.0.0.0')

Ok this upper code is run, and somehow works… but my question is, when i’am using gunicorn, i got 503/502…

My error code :

Docker-compose.py

version: '3.7'
services:

  app:
    build: 
      context: .
      dockerfile: ./app/Dockerfile
    environment: 
      - VIRTUAL_HOST=my.local
      - VIRTUAL_PORT=8000
    expose:
      - 8000
    networks: 
      - proxynet

  nginx-proxy:
    container_name: nginx-proxy
    restart: always
    image: jwilder/nginx-proxy:alpine
    ports:
      - "80:80"
      - "443:443"
    volumes:
      - ./nginx-proxy/secrets/htpasswd:/etc/nginx/htpasswd
      - ./nginx-proxy/conf.d:/etc/nginx/conf.d
      - ./nginx-proxy/vhost.d:/etc/nginx/vhost.d
      - ./nginx-proxy/html:/usr/share/nginx/html
      - ./nginx-proxy/certs:/etc/nginx/certs
      - /var/run/docker.sock:/tmp/docker.sock:ro
    networks: 
      - proxynet

networks:
  proxynet:
    external: true

Dockerfile.py

FROM python:latest
ADD ./app /root
WORKDIR /root
RUN pip install -r requirements.txt
CMD ["/usr/local/bin/gunicorn", "manage"]

requirements.txt

Flask==1.0.2
gunicorn==19.9.0

manage.py

import os
from flask import Flask 
application = Flask(__name__)

@application.route("/")
def hello():
    return "<h1 style='color:blue'>Hello There!</h1>"

if __name__ == "__main__":
    application.run(host='0.0.0.0')

This last code result error :

[error] 52#52: *1 connect() failed (111: Connection refused) while connecting to upstream, client: 172.20.0.1, server:blabla.. 

Thanks for help… Budi

[wilcool]

Is solved?

[algertgjoka]

Had the same problem with docker 19 on CentOS 8, once I downgraded to 18 everything seems to magically work again.