Docker Compose

Docker Compose is a tool for defining and running multi-container Docker applications. Key features:

• Uses YAML files to configure application services
• Allows defining multiple containers in a single file
• Simplifies complex application deployment
• Manages container networking and volume mounting
• Enables easy scaling and environment-specific configurations

Example use case: A web application with separate containers for frontend, backend, and database, all defined and orchestrated through a single docker-compose.yml file.

Typical workflow involves creating a configuration file and running docker-compose up to start the entire application stack.

Articles/Talks

• Using YAML Anchors and X Properties in Docker Compose
• Compose Bridge - Compose Bridge supplies an out-of-the box transformation for your Compose configuration file in Kubernetes files.

Examples

• Example for create a good docker-compose.yaml.

version: '3.8'
services:
 
  postgres:
    image: postgres:14.4
    container_name: postgres
    restart: on-failure:2
    ports:
      - "5432:5432"
    volumes:
      - pgdata:/var/lib/postgresql/data
    environment:
      - POSTGRES_USER=admin
      - POSTGRES_PASSWORD=password
      - POSTGRES_MULTIPLE_DATABASES=keycloak
    networks:
      - example
    healthcheck:
      test: [ "CMD", "pg_isready" ]
      interval: 30s
      timeout: 20s
      retries: 3
 
  keycloak:
    image: jboss/keycloak:16.1.1
    container_name: keycloak
    restart: on-failure:2
    ports:
      - "8070:8080"
    depends_on:
      - postgres
    environment:
      - KEYCLOAK_USER=admin
      - KEYCLOAK_PASSWORD=admin
      - DB_VENDOR=postgres
      - DB_ADDR=postgres
      - DB_DATABASE=keycloak
      - DB_USER=keycloak
      - DB_PASSWORD=keycloak
    networks:
      - example
 
networks:
  example:
 
volumes:
  pgdata:

• Build with and env file.

docker-compose build --build-args $(cat envfile)