Nginx Proxy Upstream Server Docker Compose - 502 Bad Gateway Connection Refused

Question

I am trying to containerize all things related to my web app using Docker Compose, including Nginx & SSL Certificates. To do this I am using the Nginx Proxy image from JWilder and the LetsEncrypt Companion, but am having trouble getting the nginx proxy to work, result ends up being:

Nginx 502 Bad Gateway

[error] 31160#0: *35 connect() failed (111: Connection refused) while connecting to upstream, client: xx.xx.xx.xx, server: domain.com, request: "GET /dev/ HTTP/1.1", upstream: "webapp://127.0.0.1:8080", host: "domain.com"

This only happened when trying to set up the Nginx proxy and SSL certificates so I know it's a configuration issue for either or both of these containers. If anyone can spot where I am going wrong, I would be extremely grateful!

Here are the containers in question:

version: '3.1'

networks:
  mywebapp:

services:
  nginx-proxy:
    container_name: nginx-proxy
    build: ./env/nginx-proxy
    networks:
      - mywebapp
    ports:
      - 80:80
      - 443:443
    env_file:
      - ./env/nginx-proxy/.env
    depends_on:
      - webapp
    tty: true
    volumes:
      - ./src:/home/www/mywebapp/src
      - ./storage:/home/www/storage/mywebapp
      - ./data/nginx-proxy/logs:/var/log/nginx
      - ./env/nginx-proxy/webserver/nginx.conf:/etc/nginx/nginx.conf
      - ./env/nginx-proxy/webserver/conf.d:/etc/nginx/conf.d
      - ./env/nginx-proxy/webserver/vhost.d:/etc/nginx/vhost.d
      - ./env/nginx-proxy/webserver/defaults:/etc/nginx/defaults
      - ./env/nginx-proxy/webserver/global:/etc/nginx/global
      - ./env/nginx-proxy/ssl/certs:/etc/nginx/certs
      - ./env/nginx-proxy/share:/usr/share/nginx/html
      - /var/run/docker.sock:/tmp/docker.sock:ro
    labels:
      com.github.jrcs.letsencrypt_nginx_proxy_companion.nginx_proxy: "true"

  letsencrypt:
    restart: always
    container_name: letsencrypt
    image: jrcs/letsencrypt-nginx-proxy-companion
    env_file:
      - ./env/letsencrypt/.env
    volumes:
      - ./data/letsencrypt/logs:/var/log
      - ./env/nginx-proxy/webserver/nginx.conf:/etc/nginx/nginx.conf
      - ./env/nginx-proxy/webserver/conf.d:/etc/nginx/conf.d
      - ./env/nginx-proxy/webserver/vhost.d:/etc/nginx/vhost.d
      - ./env/nginx-proxy/webserver/defaults:/etc/nginx/defaults
      - ./env/nginx-proxy/webserver/global:/etc/nginx/global
      - ./env/nginx-proxy/ssl/certs:/etc/nginx/certs
      - ./env/nginx-proxy/share:/usr/share/nginx/html
      - /var/run/docker.sock:/var/run/docker.sock:ro
    depends_on:
      - nginx-proxy

  webapp:
    container_name: webapp
    build: ./env/webapp
    hostname: webapp
    networks:
      - mywebapp
    ports:
      - 9000:9000
      - 8080:8080
    volumes:
      - ./env/composer:/home/www/.composer
      - ./env/global/bashrc:/home/www/.bashrc
      - ./data/bash/.bash_history:/home/www/.bash_history
      - ~/.ssh:/home/www/.ssh:ro
      - ~/.gitconfig:/home/www/.gitconfig:ro
      - ./storage:/home/www/storage/mywebapp
      - ./src:/home/www/mywebapp/src

Key points being:

Webapp is the source of my web application which is running PHP, MySQL and Nginx webserver. The webapp webserver exposes and listens on port 8080 to serve the PHP files.
Nginx proxy exposes standard ports 443 and 80 and proxy passes to webapp on port 8080
LetsEncrypt Companion generates the certs and renews.

Nginx Proxy server configuration:

upstream webapp {
    server 127.0.0.1:8080;
}

server {

    listen 80;
    listen [::]:80;

    server_name webapp.localhost;

    location / {
        proxy_pass http://webapp;
    }
}

server {

    # SSL configuration
    listen 443 ssl http2;
    listen [::]:443 ssl http2;
    ssl_certificate certs/default.crt;
    ssl_certificate_key certs/default.key;

    include /etc/nginx/global/ssl-params.conf;

    server_name webapp.localhost;

    location / {
        proxy_pass http://webapp;
    }
}

Webapp webserver configuration:

server {
    listen 8080;
    listen [::]:8080;

    server_name webapp.localhost;

    root /home/www/webapp/src;
    index index.php;

    include /etc/nginx/defaults/php.conf;

    location / {
        try_files $uri $uri/ /index.php$is_args$args;
    }
}

When visiting http://webapp.localhost:8080 I can see the webapp webserver serves the page no trouble, so I suspect it's something wrong with my Nginx Proxy server configuration.

Thanks for reading.

Siyu Siyu · Accepted Answer · 2019-01-06T12:48:44

Since nginx and webapp are on two separate containers, nginx can't reach webapp on localhost(127.0.0.1) as you've configured for upstream:

upstream webapp {
    server 127.0.0.1:8080;
}

Change it to webapp:8080.

Nginx Proxy Upstream Server Docker Compose - 502 Bad Gateway Connection Refused

1 Answers