NGINX reverse proxy - Docker Swarm - proxy_pass not working

Question

Today I recur to your expertise I'm a novice with some trouble that is killing my head.

I'm working with a TileServerGL server providing OpenStreet.org map in a docker container within a swarm. This server is working fine, if port 80 is exposed and redirected to, lets say 8080, I can reach its content at [IP Docker Swarm]:8080.

Now I need to add a reverse proxy in front of this container to add some security (but not yet, first I need to make the reverse proxy to work), so I add a Nginx container to the docker-compose.yml file and I'm trying to configure correctly the simplier version of a nginx reverse proxy, without much success.

I have tried:

• Running it locally with docker-compose up –build
• Running inside a swarm in my local machine with: docker stack deploy -c docker-compose.yml lab
• Running inside Vbox machines with: docker stack deploy -c docker-compose.yml lab

The domain resolution is working fine:

• my swam IP is: 192.168.1.105
• at etc/hosts I have: 192.168.1.105 app.io

When I open http://app.io at the browser I get the default Nginx welcome page. So far so good. But when I hit http://maps.app.io I still getting the same default welcome page.

The Nginx server log:

10.255.0.2 - - [01/Dec/2018:00:55:59 +0000] "GET / HTTP/1.1" 304 0 "-" "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.110 Safari/537.36" "-"

I would not appeal to your help with out before reading every post, article , tutorial that I've found on the internet. As I see it the “nginx.conf” file is correct, but the reality show me that I'm undoubtedly wrong and blind to my mistake. I'll really appreciate your help.

I'm running:

• linux Mint 19 Tara
• Docker version: Docker version 18.09.0, build 4d60db4
• Docker machine version: docker-machine version 0.16.0, build 702c267f

The docker-compose.yml file:

version: "3.5"

networks:
  nginx-net:
    driver: overlay

services:
  maps:
    image: xxxx/xxxx:mapstiles
    volumes:
      - ./server_mapstiles/app/data:/data
    networks:
      - nginx-net
    deploy:
      restart_policy:
        condition: on-failure
      replicas: 1

  nginx:
    image: nginx:1.15.7
    container_name: nginx
    ports:
      - "80:80"
    networks:
      - nginx-net
    volumes:
     - ./server_nginx/nginx.conf:/etc/nginx/proxy.conf:ro
    deploy:
      restart_policy:
        condition: on-failure
      replicas: 1
    depends_on:
     - maps

The nginx conf file is:

server {
        listen          80;
        server_name     maps.app.io;

        location / {
                proxy_pass  http://:maps:80;
                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;
                resolver        127.0.0.11;
        }
}

Answer 1

You have some nasty invalid syntax there for your proxy_pass directive.

proxy_pass http://:maps:80; isn't a valid proxy pass destination, http://:maps:80 wil fail because of that first colon after the // .

Try proxy_pass http://maps:80; but keep in mind the NGINX configuration pitfall of using a hostname to define a location/proxy pass destination/etc.