How do I connect the PhpMyAdmin container to MariaDB on the host?

Docker Engine Compose
1

Hello,
The compose file looks like this:

phpmyadmin:
    image: phpmyadmin:latest
    container_name: phpmyadmin
    restart: unless-stopped
#    network_mode: host
    environment:
      PMA_HOST: host.docker.internal
      MYSQL_ROOT_PASSWORD: 123456
    ports:
      - "127.0.0.1:8080:80"
    extra_hosts:
      - "host.docker.internal:host-gateway"

The Nginx configuration is as follows:

...
location /phpmyadmin/ {
        proxy_pass http://127.0.0.1:8080/;  # Matches your compose port binding
        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-Proto $scheme;
        proxy_set_header X-Script-Name /phpmyadmin;  # Critical for path handling
        
        # WebSocket support
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "upgrade";
        
        # Buffer settings
        proxy_buffer_size 128k;
        proxy_buffers 4 256k;
        proxy_busy_buffers_size 256k;
        
        # Security headers
        add_header X-Frame-Options "SAMEORIGIN";
        add_header X-Content-Type-Options "nosniff";
        add_header X-XSS-Protection "1; mode=block";
    }

    # Redirect /phpmyadmin to /phpmyadmin/
    location = /phpmyadmin {
        return 301 /phpmyadmin/;
    }

MariaDB is also running on the host as follows:

# netstat -tulnp | grep 3306
tcp        0      0 0.0.0.0:3306            0.0.0.0:*               LISTEN      3248362/mariadbd

When I enter my username and password in PhpMyAdmin, I get the following error:

mysqli::real_connect(): (HY000/2002): No route to host

Thank you.

2

I edited the compose file as below:

  phpmyadmin:
    image: phpmyadmin:latest
    container_name: phpmyadmin
    restart: unless-stopped
    environment:
      PMA_SOCKET: /run/mysqld/mysqld.sock
      PMA_HOST: 172.20.2.58
      MYSQL_ROOT_PASSWORD: 123456
    ports:
      - "127.0.0.1:8080:80"
    volumes:
      - /var/run/mysqld/mysqld.sock:/var/run/mysqld/mysqld.sock

The new Nginx configuration is as follows:

location /phpmyadmin/ {
        proxy_pass http://127.0.0.1:8080/;
        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-Proto $scheme;
        proxy_set_header X-Script-Name /phpmyadmin;

        # Add these critical headers:
        proxy_set_header X-Forwarded-Host $host;
        proxy_set_header X-Forwarded-Port $server_port;
        proxy_set_header X-Forwarded-Server $host;

        # Cookie path rewrite
        proxy_cookie_path / /phpmyadmin/;

        # Rest of your existing config...
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "upgrade";

        # Buffer settings
        proxy_buffer_size 128k;
        proxy_buffers 4 256k;
        proxy_busy_buffers_size 256k;

        # Security headers
        add_header X-Frame-Options "SAMEORIGIN";
        add_header X-Content-Type-Options "nosniff";
        add_header X-XSS-Protection "1; mode=block";
    }

    # Redirect /phpmyadmin to /phpmyadmin/
    location = /phpmyadmin {
        return 301 /phpmyadmin/;
    }

And the problem is solved.