DEV Community

SOVANNARO
SOVANNARO

Posted on

3 Microservices, 1 YAML File, 1 Command: The Power of Docker Compose

#docker

🛠️ Problem: Too Many docker run Commands

Right now, you have Docker images for three microservices:

  • accounts
  • loans
  • cards

To run each one, you’d normally do:

docker run -p <port>:<port> <image-name>
Enter fullscreen mode Exit fullscreen mode

But imagine doing that for 100 microservices or even just multiple instances.
💡 Manually running each with docker run becomes slow and painful.

✅ Solution: Use Docker Compose

What is Docker Compose?

Docker Compose is a tool that lets you:

  • Define all microservices in one YAML file.
  • Start or stop all services with just one command.

👉 Instead of typing docker run multiple times, you write everything once in a file called docker-compose.yml.

⚙️ What Can Docker Compose Do?

  • Start all microservices with docker compose up
  • Stop everything with docker compose down
  • Set memory limits
  • Link services together with a shared network
  • View logs, restart services, and more

Docker Compose is installed automatically with Docker Desktop

📄 Let's Create a docker-compose.yml

Put the file anywhere you want (e.g., in your accounts project folder).

Step-by-step Structure: 

services: accounts: image: "your-username/accounts:s4" container_name: accounts-ms ports: - "8080:8080" deploy: resources: limits: memory: 700m networks: - easybank loans: image: "your-username/loans:s4" container_name: loans-ms ports: - "8090:8090" deploy: resources: limits: memory: 700m networks: - easybank cards: image: "your-username/cards:s4" container_name: cards-ms ports: - "9000:9000" deploy: resources: limits: memory: 700m networks: - easybank networks: easybank: driver: bridge
Enter fullscreen mode Exit fullscreen mode

🔍 Explanation:

Key Meaning
services: Section where you define each microservice
image: The Docker image to use (add your Docker Hub username)
container_name: Give your container a readable name
ports: Map internal ports to your machine
deploy > resources > limits: Restrict memory usage
networks: Allow microservices to talk to each other
easybank (at bottom): Creates a shared network all services use

🤝 Why Use networks:?

Without a shared network, microservices can’t talk to each other.
Adding them to the same network (like easybank) enables communication.

✅ Final Steps

To check if Docker Compose is installed:

docker compose version
Enter fullscreen mode Exit fullscreen mode

If not, visit the Docker Compose install page and follow the steps for your OS.

🎯 What’s Next?

Now that your docker-compose.yml is ready, you can:

Start all services with: 

docker compose up
Enter fullscreen mode Exit fullscreen mode

Stop all services with: 

docker compose down
Enter fullscreen mode Exit fullscreen mode

🧠 Summary

  • docker-compose.yml lets you manage all services in one file.
  • You define images, ports, memory limits, and networks.
  • Use docker compose up to launch everything with one command.
  • It saves time and avoids manual repetition.

Top comments (0)