无法将 Ngxin 反向代理连接到 Django 容器（Docker）上的 Gunicorn

Question

I've being trying to make a stack with a Nginx container receiving requests as a reverse proxy to my Django container with Gunicorn (not worrying about static files or DB for now), but I keep getting a 502 Bad Gateway error on Nginx.

Nginx logs:

2017/04/28 12:10:10 [notice] 1#1: using the "epoll" event method
2017/04/28 12:10:10 [notice] 1#1: nginx/1.12.0
2017/04/28 12:10:10 [notice] 1#1: built by gcc 6.3.0 20170205 (Debian 6.3.0-6) 
2017/04/28 12:10:10 [notice] 1#1: OS: Linux 4.4.0-63-generic
2017/04/28 12:10:10 [notice] 1#1: getrlimit(RLIMIT_NOFILE): 1048576:1048576
2017/04/28 12:10:10 [notice] 1#1: start worker processes
2017/04/28 12:10:10 [notice] 1#1: start worker process 7
2017/04/28 12:10:10 [notice] 1#1: start worker process 8
2017/04/28 12:10:10 [notice] 1#1: start worker process 9
172.19.0.1 - - [28/Apr/2017:12:10:17 +0000] "GET / HTTP/1.1" 502 575 "-" "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/56.0.2924.87 Safari/537.36"
2017/04/28 12:10:17 [error] 7#7: *2 connect() failed (111: Connection refused) while connecting to upstream, client: 172.19.0.1, server: , request: "GET / HTTP/1.1", upstream: "http://127.0.53.53:8000/", host: "localhost"
2017/04/28 12:10:28 [info] 7#7: *1 client closed connection while waiting for request, client: 172.19.0.1, server: 0.0.0.0:80
2017/04/28 12:10:28 [info] 7#7: *4 client closed connection while waiting for request, client: 172.19.0.1, server: 0.0.0.0:80
2017/04/28 12:10:28 [info] 7#7: *3 client closed connection while waiting for request, client: 172.19.0.1, server: 0.0.0.0:80

Gunicorn:

[2017-04-28 12:09:02 +0000] [1] [INFO] Starting gunicorn 19.7.1
[2017-04-28 12:09:02 +0000] [1] [INFO] Listening at: http://0.0.0.0:8000 (1)
[2017-04-28 12:09:02 +0000] [1] [INFO] Using worker: sync
[2017-04-28 12:09:02 +0000] [9] [INFO] Booting worker with pid: 9
[2017-04-28 12:09:02 +0000] [11] [INFO] Booting worker with pid: 11
[2017-04-28 12:09:02 +0000] [13] [INFO] Booting worker with pid: 13

Dockerfile for nginx:

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

nginx.conf file:

worker_processes 3;

events { 
    worker_connections 1024; 
}

error_log /var/log/nginx/error.log debug;

http {
    sendfile on;

    upstream app_servers {
        server app:8000;
    }

    server {
        listen 80;

        location / {
            proxy_pass         http://app_servers;
            proxy_redirect     off;
            proxy_set_header   Host $host;
            proxy_set_header   X-Real-IP $remote_addr;
            proxy_set_header   X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_set_header   X-Forwarded-Host $server_name;
        }
    }
}

Dockerfile for django:

FROM python:3.5-slim

ENV PYTHONUNBUFFERED 1
RUN mkdir /code

WORKDIR /code

ADD . /code

EXPOSE 8000

RUN pip install -r requirements.txt
RUN python manage.py collectstatic --noinput

CMD ["gunicorn", "marcos.wsgi:application", "--bind", "0.0.0.0:8000", "--workers", "3"]

I've tried to create a network manually and placing both containers in it running the following commands.

docker run --network marcos_net -h app marcos
docker run --network marcos_net -h nginx -p 80:80 nginx

And with a docker-compose.yml file:

version: '3'  
services:  
  app:
    image: myrepo/app
  nginx:
    image: myrepo/nginx
    ports:
      - "80:80"
    depends_on:
      - app

I've also tried to access the containers to ping one another like it says in the docs ( https://docs.docker.com/engine/tutorials/networkingcontainers/ ) and they are in fact in the same network. Also checked with the docker network inspect command.

Both ways log the same error printed above.

I've seen some similar questions, but they are from different docker-compose file versions, and they didn't solve the problem for me, so I don't think it is the same problem.

Answer 1

Looks like your nginx isn't connected to gunicorn properly. Try putting port parameter in your docker compose file.

services:  
  app:
    image: myrepo/app
    ports:
      - "8000:8000"

Also, here is an example of how you may set it up.

https://github.com/wiamsuri/django-gunicorn-nginx-docker