Hello, fellow developers and digital denizens! If you've ever felt like your computer is a buffet for hungry databases, munching on your memory like it's an all-you-can-eat, you're not alone. I've been in those shoes, and let me tell you, it's not a walk in the park.

The Eureka Moment: Docker to the Rescue!

One day, amidst my frustration, a light bulb went off. 💡 Why not use Docker to host all these databases? That way, I don't need to get into the nitty-gritty of configurations or let my PC run a marathon with databases on its back.

Getting Started: The Magic of Docker-Compose

First things first, let's set up our magical box. Create a folder, let's call it "DB," and inside, make a file named docker-compose.yaml. Here's the spell you need:

# docker-compose
version: '3.1'
services:

  # MySQL database
  mysql:
    image: mysql:8.0
    environment:
      MYSQL_ROOT_PASSWORD: somePassword
    ports:
      - "3306:3306"
    volumes:
      - ./mysql_data:/var/lib/mysql

  # PostgreSQL database
  postgres:
    image: postgres:13
    environment:
      POSTGRES_PASSWORD: "somePassword"
      POSTGRES_USER: "postgres"
      POSTGRES_DB: "postgres"
    ports:
      - "5432:5432"
    volumes:
      - ./postgres_data:/var/lib/postgresql/data
      - ./postgresql.conf:/etc/postgresql/postgresql.conf
      - ./pg_hba.conf:/etc/postgresql/pg_hba.conf

  # SQL Server
  mssql:
    image: mcr.microsoft.com/mssql/server
    environment:
      SA_PASSWORD: "SomePassword"
      ACCEPT_EULA: "Y"
    ports:
      - "1433:1433"
    volumes:
      - ./mssql_data:/var/opt/mssql

  # MongoDB
  mongo:
    image: mongo:latest
    environment:
      MONGO_INITDB_ROOT_USERNAME: root
      MONGO_INITDB_ROOT_PASSWORD: somePassword
    ports:
      - "27017:27017"
    volumes:
      - ./mongo_data:/data/db

  # Nginx
  nginx:
    image: nginx:latest
    ports:
      - "80:80"
    volumes:
      - ./nginx.conf:/etc/nginx/nginx.conf

volumes:
  mysql_data:
  postgres_data:
  mongo_data:

Almost There: Configuring Our Proxy

We're on the home stretch, folks! Now, it's time to set up our domain:

1. Grab your server's public IP, like '167.71.xxx.xx', and set up an A record in your domain's DNS settings.

2. I went fancy and created a subdomain like db.myDomain.com

🚫 Pro Tip: If you're using Cloudflare, keep the proxy off. We don't want extra magic interfering here.

Next, in our "DB" folder, create a nginx.conf file for our proxy settings:

# nginx.conf
events {}

http {
    server {
        listen 80;
        server_name <Your_DOMAIN>;

        # MySQL
        location /mysql/ {
            proxy_pass http://mysql:3306;
            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;
        }

        # PostgreSQL
        location /postgres/ {
            proxy_pass http://postgres:5432;
            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;
        }

        # SQL Server
        location /mssql/ {
            proxy_pass http://mssql:1433;
            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;
        }

        # MongoDB
        location /mongo/ {
            proxy_pass http://mongo:27017;
            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;
        }
    }
}

Remember to replace <Your_DOMAIN> with your domain. In my case, it's db.mydomainName.com.

The Final Touches: PostgreSQL Configuration

PostgreSQL can be a bit moody when connecting remotely. Let's soothe it with a pg_hba.conf and a postgresql.conf:

#pg_hba.conf
# IPv4 local connections:
host    all             all             0.0.0.0/0            md5
# IPv6 local connections:
host    all             all             ::/0                 md5

#postgresql.conf

listen_addresses = '*'

Ready, Set, Docker!

Finally, just run docker-compose up -d, and voila! Your databases are ready to serve you, not the other way around.

Local Setup?

If you're setting this up locally, just replace Your_Domain in nginx.conf with your system's IP.

And that's how I turned my database dilemma into a Docker delight! If you have any tips, tricks, or tales of your own, drop them in the comments. Let's learn from each other's epic IT adventures. Cheers and happy coding! 🚀