How can I fix this 502 Bad Gateway?

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Bugs or Features

I am trying to run a WordPress site inside of a docker container on Ubuntu VPS using Nginx-Proxy.

I created the following docker-compose.yml file

version: '3.4'
services:
    nginx-proxy:
        image: jwilder/nginx-proxy
        ports:
            - 80:80
            - 443:443
        restart: always
        networks:
            - external
        volumes:
            - wordpress:/var/www/html
        ports:
            - 5500:5500
    wordpress_app:
        image: wordpress
        restart: always
        environment:
            - VIRTUAL_HOST=sub.domain.com
            - VIRTUAL_PORT=5500
            - WORDPRESS_DB_HOST=db
            - WORDPRESS_DB_USER=db_username
            - WORDPRESS_DB_PASSWORD=db_password
            - WORDPRESS_DB_NAME=db_name
        depends_on:
            - nginx-proxy
            - db
        networks:
            - internal
            - external
        volumes:
            - wordpress:/var/www/html
        ports:
            - 5500:5500
    db:
        image: mysql:latest
        restart: always
        hostname: mysql
        environment:
            - VIRTUAL_PORT=3306
            - MYSQL_DATABASE=db_name
            - MYSQL_USER=db_username
            - MYSQL_PASSWORD=db_password
            - MYSQL_ROOT_PASSWORD=root_password
        networks:
            - internal
        volumes:
            - db:/var/lib/mysql
        ports:
            - 3306:3306
volumes:
    wordpress:
    db:

networks:
    internal:
    external:

Now, executing docker-compose up prints the following

Attaching to root_db_1, root_nginx-proxy_1, root_wordpress_app_1
db_1                 | 2020-10-12 16:34:17+00:00 [Note] [Entrypoint]: Entrypoint script for MySQL Server 8.0.21-1debian10 started.
db_1                 | 2020-10-12 16:34:18+00:00 [Note] [Entrypoint]: Switching to dedicated user 'mysql'
db_1                 | 2020-10-12 16:34:18+00:00 [Note] [Entrypoint]: Entrypoint script for MySQL Server 8.0.21-1debian10 started.
db_1                 | 2020-10-12T16:34:19.127860Z 0 [System] [MY-010116] [Server] /usr/sbin/mysqld (mysqld 8.0.21) starting as process 1
db_1                 | 2020-10-12T16:34:19.146953Z 1 [System] [MY-013576] [InnoDB] InnoDB initialization has started.
db_1                 | 2020-10-12T16:34:20.318195Z 1 [System] [MY-013577] [InnoDB] InnoDB initialization has ended.
nginx-proxy_1        | WARNING: /etc/nginx/dhparam/dhparam.pem was not found. A pre-generated dhparam.pem will be used for now while a new one
nginx-proxy_1        | is being generated in the background.    Once the new dhparam.pem is in place, nginx will be reloaded.
nginx-proxy_1        | forego         | starting dockergen.1 on port 5000
nginx-proxy_1        | forego         | starting nginx.1 on port 5100
nginx-proxy_1        | dockergen.1 | 2020/10/12 16:34:18 Generated '/etc/nginx/conf.d/default.conf' from 2 containers
nginx-proxy_1        | dockergen.1 | 2020/10/12 16:34:18 Watching docker events
nginx-proxy_1        | dockergen.1 | 2020/10/12 16:34:20 Generated '/etc/nginx/conf.d/default.conf' from 3 containers
nginx-proxy_1        | dockergen.1 | 2020/10/12 16:34:20 Received event start for container a6b94da9d7a7
nginx-proxy_1        | dockergen.1 | 2020/10/12 16:34:20 Contents of /etc/nginx/conf.d/default.conf did not change. Skipping notification 'nginx -s reload'
db_1                 | 2020-10-12T16:34:20.960375Z 0 [System] [MY-011323] [Server] X Plugin ready for connections. Bind-address: '::' port: 33060, socket: /var/run/mysqld/mysqlx.sock
db_1                 | 2020-10-12T16:34:21.394031Z 0 [Warning] [MY-010068] [Server] CA certificate ca.pem is self signed.
db_1                 | 2020-10-12T16:34:21.394509Z 0 [System] [MY-013602] [Server] Channel mysql_main configured to support TLS. Encrypted connections are now supported for this channel.
db_1                 | 2020-10-12T16:34:21.425181Z 0 [Warning] [MY-011810] [Server] Insecure configuration for --pid-file: Location '/var/run/mysqld' in the path is accessible to all OS users. Consider choosing a different directory.
db_1                 | 2020-10-12T16:34:21.566194Z 0 [System] [MY-010931] [Server] /usr/sbin/mysqld: ready for connections. Version: '8.0.21'    socket: '/var/run/mysqld/mysqld.sock'    port: 3306    MySQL Community Server - GPL.
wordpress_app_1      | AH00558: apache2: Could not reliably determine the server's fully qualified domain name, using 172.25.0.3. Set the 'ServerName' directive globally to suppress this message
wordpress_app_1      | AH00558: apache2: Could not reliably determine the server's fully qualified domain name, using 172.25.0.3. Set the 'ServerName' directive globally to suppress this message
wordpress_app_1      | [Mon Oct 12 16:34:22.661957 2020] [mpm_prefork:notice] [pid 1] AH00163: Apache/2.4.38 (Debian) PHP/7.4.11 configured -- resuming normal operations
wordpress_app_1      | [Mon Oct 12 16:34:22.662180 2020] [core:notice] [pid 1] AH00094: Command line: 'apache2 -D FOREGROUND'
nginx-proxy_1        | 2020/10/12 16:34:23 [notice] 49#49: signal process started
nginx-proxy_1        | Generating DH parameters, 2048 bit long safe prime, generator 2
nginx-proxy_1        | This is going to take a long time
nginx-proxy_1        | dhparam generation complete, reloading nginx

Then when I make a request to http://sub.domain.com I get the 502 error but I also get this in the server’s log

nginx-proxy_1        | nginx.1        | 2020/10/12 16:35:07 [error] 51#51: *1 connect() failed (111: Connection refused) while connecting to upstream, client: MY_PERSOANL_IP_ADDRESS, server: sub.domain.com, request: "GET / HTTP/1.1", upstream: "http://172.25.0.3:5500/", host: "sub.domain.com"
nginx-proxy_1        | nginx.1        | sub.domain.com MY_PERSOANL_IP_ADDRESS - - [12/Oct/2020:16:35:07 +0000] "GET / HTTP/1.1" 502 157 "-" "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:81.0) Gecko/20100101 Firefox/81.0"
nginx-proxy_1        | nginx.1        | sub.domain.com MY_PERSOANL_IP_ADDRESS - - [12/Oct/2020:16:35:08 +0000] "GET /favicon.ico HTTP/1.1" 502 157 "http://sub.domain.com/" "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:81.0) Gecko/20100101 Firefox/81.0"
nginx-proxy_1        | nginx.1        | 2020/10/12 16:35:08 [error] 51#51: *1 no live upstreams while connecting to upstream, client: MY_PERSOANL_IP_ADDRESS, server: sub.domain.com, request: "GET /favicon.ico HTTP/1.1", upstream: "http://sub.domain.com/favicon.ico", host: "sub.domain.com", referrer: "http://sub.domain.com/"

Potential Issue

The logs states

2020/10/12 16:34:20 Generated ‘/etc/nginx/conf.d/default.conf’ from 3 containers

However, while docker containers are running, I execute cd /etc/nginx/conf.d but I get -bash: cd: /etc/nginx/conf.d/: No such file or directory. Should the file /etc/nginx/conf.d/default.conf actually exists?

What can be causing this issue? How can I fix it?

[jaywork2020]

@tkw1536 Thank you for you assistance. I have improved the docker-compose.yml file to the following

version: "3"
services:
    nginx-proxy:
        image: jwilder/nginx-proxy
        container_name: nginx-proxy
        ports:
            - "80:80"
            - "443:443"
        restart: always
        volumes:
            - /var/run/docker.sock:/tmp/docker.sock:ro
            - /etc/certificates:/etc/nginx/certs

    wordpress_app:
        image: wordpress:latest
        restart: always
        container_name: wordpress_app
        environment:
            VIRTUAL_HOST: usa.doamin.com
            WORDPRESS_DB_HOST: mysql_server:3306
            WORDPRESS_DB_USER: db_username
            WORDPRESS_DB_PASSWORD: db_password
            WORDPRESS_DB_NAME: wordpress_app
        depends_on:
            - nginx-proxy
            - mysql_server
        volumes:
            - wordpress_app_public_html:/var/www/html
        expose:
            - 80

    phpmyadmin:
        image: phpmyadmin
        container_name: phpmyadmin
        restart: always
        environment:
            VIRTUAL_HOST: adminusa.domain.com
            PMP_HOST: mysql_server:3306
            MYSQL_USERNAME: root
            MYSQL_ROOT_PASSWORD: db_root_password
        depends_on:
            - nginx-proxy
            - mysql_server
        expose:
            - 80
    mysql_server:
        image: mysql:latest
        restart: always
        container_name: mysql_server
        environment:
            MYSQL_DATABASE: wordpress_app
            MYSQL_USER: db_username
            MYSQL_PASSWORD: db_password
            MYSQL_ROOT_PASSWORD: db_root_password
        volumes:
            - mysql_server_data:/var/lib/mysql

volumes:
    wordpress_app_public_html:
    mysql_server_data:

networks:
    default:
       external:
           name: nginx-proxy

Additionally, in the /etc/certificates path, I have the following 4 files for the https certificate

• adminusa.domain.com.crt
• adminusa.domain.com.key
• usa.domain.com.crt
• usa.domain.com.key

When browsing http://usa.domain.com I get the “503 Service Temporarily Unavailable” error. At the same time, when browsing https://usa.domain.com I get a white page.

Any idea on what could be causing the 503 error now?

[dequeues]

Is this a dup of #490?

I’m hitting this too. I have another container that works perfectly, so I’m not sure what the difference is. Been trying all day to no avail. The container works perfectly when I drop the environment variables (VIRTUAL_HOST and VIRTUAL_PORT) that trigger nginx-proxy and access it directly by IP, but as soon as I add the environment variables, I get the errors about no live upstreams while connecting to upstream and connect() failed (111: Connection refused) while connecting to upstream

Edit: I see, I thought we had to expose the published port, rather than the internal host. Publishing ports is not necessary at all, so I fixed it by updating the port the service within my container listens to. I ended up hitting the same problem again, but it turned out to be because I forgot to add the correct network to the container, which I was able to see by following the debugging steps in the README.

Could you share your config? I’m having this exact same issue in #2049