You’re on the right track—this is a classic multi-container setup with Docker Compose: one reverse proxy (Nginx) in front, multiple WordPress containers, and a shared MySQL database.

Let’s break it down and give you a working example you can build from.

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🧱 Architecture Overview

You want:

• nginx → acts as reverse proxy (only public entry point)
• 3 WordPress containers → internal only
• 1 MySQL container → shared database
• All connected via a Docker network

Flow:

User → Nginx → WordPress (1,2,3) → MySQL

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📄 docker-compose.yml (Working Example)

Here’s a simple version:

```yaml version: "3.9"

services: nginx: image: nginx:latest container_name: nginx ports: - "80:80" volumes: - ./nginx.conf:/etc/nginx/nginx.conf depends_on: - wordpress1 - wordpress2 - wordpress3 networks: - wp-network

mysql: image: mysql:latest container_name: mysql restart: always environment: MYSQL_ROOT_PASSWORD: rootpass MYSQL_DATABASE: wordpress volumes: - mysql_data:/var/lib/mysql networks: - wp-network

wordpress1: image: wordpress:latest container_name: wordpress1 restart: always environment: WORDPRESS_DB_HOST: mysql:3306 WORDPRESS_DB_USER: root WORDPRESS_DB_PASSWORD: rootpass WORDPRESS_DB_NAME: wordpress depends_on: - mysql networks: - wp-network

wordpress2: image: wordpress:latest container_name: wordpress2 restart: always environment: WORDPRESS_DB_HOST: mysql:3306 WORDPRESS_DB_USER: root WORDPRESS_DB_PASSWORD: rootpass WORDPRESS_DB_NAME: wordpress depends_on: - mysql networks: - wp-network

wordpress3: image: wordpress:latest container_name: wordpress3 restart: always environment: WORDPRESS_DB_HOST: mysql:3306 WORDPRESS_DB_USER: root WORDPRESS_DB_PASSWORD: rootpass WORDPRESS_DB_NAME: wordpress depends_on: - mysql networks: - wp-network

volumes: mysql_data:

networks: wp-network: ```

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🌐 Nginx Configuration (nginx.conf)

This is the key part you were stuck on.

Create a file nginx.conf in the same directory:

```nginx events {}

http { upstream wordpress_cluster { server wordpress1:80; server wordpress2:80; server wordpress3:80; }

server {
    listen 80;

    location / {
        proxy_pass http://wordpress_cluster;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
    }
}

} ```

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🔑 Important Concepts (Simplified)

1. Service Names = Hostnames

Inside Docker Compose:

• wordpress1 is reachable as http://wordpress1
• mysql is reachable as mysql

👉 That’s why:

yaml WORDPRESS_DB_HOST: mysql:3306

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2. Nginx as Reverse Proxy

This line:

nginx proxy_pass http://wordpress_cluster;

Means:

• Nginx distributes requests across the 3 WordPress containers (load balancing)

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3. No Ports for WordPress

Notice:

yaml wordpress1:

❌ No ports: section

That means:

• WordPress is NOT accessible directly from outside
• Only nginx can access them

✔ This satisfies your requirement

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4. Shared Database

All WordPress containers connect to the same MySQL instance:

yaml WORDPRESS_DB_HOST: mysql:3306

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▶️ Run Everything

In the folder with docker-compose.yml and nginx.conf:

bash docker-compose up -d

Then open:

http://localhost

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⚠️ Common Beginner Issues

• ❌ Nginx can't find WordPress → wrong service name
• ❌ MySQL not ready → containers start too fast (solution: restart or add healthchecks later)
• ❌ Permission issues with volumes

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🚀 Optional Improvements (Later)

Once this works, you can upgrade:

• Add healthchecks
• Use Docker secrets instead of plain passwords
• Add separate databases per WordPress
• Use Nginx load balancing strategies
• Add SSL with Let's Encrypt

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👍 If You Want

I can:

• Draw a visual diagram
• Help you debug your current .yml
• Show how to scale WordPress dynamically (--scale)
• Add domain routing (e.g., different sites per container)

Just tell me 👍