Connecting A Dockerized Laravel App To Internal Mysql Service

Running Laravel inside Docker is a modern approach to building and deploying apps consistently across various environments. If you're containerizing your Laravel app and want to connect it to a MySQL database without installing MySQL on your server, Docker Compose makes this process smooth and efficient.

In this guide, we’ll walk through how to spin up a Laravel container and link it to a MySQL container using Docker Compose. However, if you prefer using an external MySQL service rather than a containerized one, I have written a quick guide How To Connect A Dockerized Laravel App To A Host Mysql Server On A Linux Vps

Prerequisites

Make sure the following are ready:

• A pre-built Docker image for your Laravel app (e.g., published on Docker Hub)
• Docker and Docker Compose are installed on your VPS

Step 1: Create Docker Compose File

Create a docker-compose.yml file in your preferred directory on your VPS.

Here is a sample content:

services:
 app:
   image: <username>/<your-image-name>
   container_name: laravel-app
   ports:
     - "8090:80"
     - "5173:5173"
   environment:
     DB_HOST: ${DB_HOST} 
     DB_PORT: ${DB_PORT}
     DB_DATABASE: ${DB_DATABASE}
     DB_USERNAME: ${DB_USERNAME}
     DB_PASSWORD: ${DB_PASSWORD}
   env_file:
     - .env
   volumes:
     - ./.env.production:/var/www/html/.env:ro
   networks:
     - laravel-app-network
   depends_on:
     - db
   healthcheck:
     test: ["CMD-SHELL", "curl -f http://localhost || exit 1"]
     interval: 30s
     timeout: 10s
     retries: 5
 db:
   image: mysql:8.0
   container_name: laravel-app-db
   restart: always
   environment:
     MYSQL_ROOT_PASSWORD: ${MYSQL_ROOT_PASSWORD}
     MYSQL_DATABASE: ${DB_DATABASE}
     MYSQL_USER: ${DB_USERNAME}
     MYSQL_PASSWORD: ${DB_PASSWORD}
   ports:
     - "3307:3306"
   volumes:
     - db_data:/var/lib/mysql
   networks:
     - laravel-app-network
volumes:
 db_data:
networks:
 laravel-app-network:
   driver: bridge

Note: We expose MySQL to the host on port 3307 to avoid conflicts, but internally it runs on 3306.

Step 2: Create the .env File

In the same directory as your docker-compose.yml, create a .env file with the following content:

DB_CONNECTION=mysql
DB_HOST=db
DB_PORT=3306
DB_DATABASE=laravel_db
DB_USERNAME=laravel_user
DB_PASSWORD=laravel_pass
MYSQL_ROOT_PASSWORD=secret_root_pass

Also, create .env.production if your Laravel image expects it to be mounted at /var/www/html/.env.

💡 Why DB_HOST=db?
In Docker Compose, services can reach each other by their service names.
Since our MySQL container is named db, Laravel uses DB_HOST=db to connect to it internally — not localhost.

Step 3: Start Everything Up

From the directory containing your docker-compose.yml, run:

docker-compose up -d

Step 4: Verify MySQL Connection

Access the app container through:

docker exec -it laravel-app bash

Install MySQL client (optional, for manual testing):
apt update && apt install -y default-mysql-client
mysql -h db -u laravel_user -p

When prompted, enter laravel_pass. You should land in the MySQL prompt, implying you are connected.

Assumption

This guide assumes:

• Laravel app image is pulled from Docker Hub (e.g., username/your-image-name).
• The MySQL service runs as a container, not on the host system.