====== Docker Compose =====

Define and run multi-container applications with a single YAML file.

> //Docker Compose simplifies managing multiple containers that work together.//

===== Overview =====

Docker Compose allows you to define and run multi-container applications using a single YAML file. Instead of running each container separately, you define all services in one place and start them all with a single command.

===== Basic Structure =====

```yaml
services:
  web:
    image: nginx:latest
    ports:
      - "8080:80"
    networks:
      - app-network

  db:
    image: postgres:16
    environment:
      POSTGRES_PASSWORD: example
    volumes:
      - postgres-data:/var/lib/postgresql/data
    networks:
      - app-network

networks:
  app-network:

volumes:
  postgres-data:
```

===== Docker Compose Commands =====

```bash
docker compose up -d          # Start services in background
docker compose down           # Stop and remove containers
docker compose logs           # View logs
docker compose ps             # List containers
docker compose restart        # Restart services
docker compose up -d --build  # Rebuild and start
```

===== Service Discovery =====

Containers on the same network can reach each other using service names. In the example above, the web container can reach the database at `db:5432`.

===== Key Concepts =====

**Services:**
  * Define each container as a service
  * Specify image, ports, volumes, networks
  * Service name becomes hostname for other containers

**Networks:**
  * Enable communication between containers
  * Default network created automatically
  * Custom networks for isolation

**Volumes:**
  * Persist data across container restarts
  * Named volumes managed by Docker
  * Bind mounts link host directories

===== References =====

  * [[https://docs.docker.com/get-started/workshop/08_using_compose/|Use Docker Compose]]
  * [[https://docs.docker.com/get-started/docker-concepts/the-basics/what-is-docker-compose/|What is Docker Compose?]]
  * [[https://linuxize.com/post/docker-compose/|Docker Compose: Define and Run Multi-Container Apps]]
  * [[https://docs.docker.com/reference/compose-file/services/|Define services in Docker Compose]]

===== See Also =====

  * [[hosting:docker:start|Docker Overview]]
  * [[hosting:docker:concepts|Basic Docker Concepts]]

Last updated: 2026-06-19
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