Docker Compose Overview

Docker compose files are used to define and run multi-container applications in one configuration file.
The standard name for this file is docker-compose.yml.

Here is an example of a docker-compose.yml file with the official Hello World image:

docker-compose.yml


version: '3.8'
services:
  hello-world:
    image: hello-world
    container_name: hello-world
    restart: unless-stopped

Overview


version: '3.9'
 
# General Docker Compose Example
 
# Project or stack name
name: MyProject
 
services:
 
  # Web server service (e.g., NGINX)
  web:
    image: nginx:latest                 # Use latest official NGINX image
    container_name: web-server          # Custom container name
    restart: always                     # Always restart container on failure
    ports:
      - "8080:80"                       # Map host port 8080 to container port 80
    volumes:
      - ./nginx/conf:/etc/nginx/conf.d:ro  # Mount local config folder as read-only
    networks:
      - my-network                      # Attach to custom network
 
  # Backend API service (Node.js example)
  api:
    build:
      context: ./api                     # Directory with Dockerfile
      dockerfile: Dockerfile
    container_name: api-service          # Custom container name
    working_dir: /app                    # Set working directory
    command: node server.js              # Command to start the service
    restart: always
    expose:
      - 3000                             # Expose internal port to other containers
    volumes:
      - ./api:/app                        # Mount local code for live updates
    networks:
      - my-network
    # depends_on:
    #   - db                               # Optional dependency on database, db has to be running first to start the service
 
  # Database service (e.g., PostgreSQL)
  db:
    image: postgres:15                    # Official PostgreSQL image
    container_name: postgres-db
    restart: always
    environment:
      POSTGRES_USER: user
      POSTGRES_PASSWORD: password
      POSTGRES_DB: mydb
    ports:
      - "5432:5432"
    volumes:
      - db-data:/var/lib/postgresql/data
    networks:
      - my-network
 
# Define custom network
networks:
  my-network:
 
# Define named volumes
volumes:
  db-data:

Start commands

Start all services defined in docker-compose.yml

Terminal


docker-compose up -d

Stop commands

Stop all running services

Terminal


docker-compose stop

Stop and remove all containers, networks, and volumes defined in the Compose file

Terminal


docker-compose down

Rebuild images and restart all services

Terminal


docker-compose up -d --build

Log commands

View logs for all services

Terminal


docker-compose logs -f

View logs for a specific service

Terminal


docker-compose logs -f api

Restart a specific service

Terminal


docker-compose restart api

Include a .env file

Sometimes you may want to include a .env file in your project to store secrets like in the db-service.
This can be done by adding a .env file to the root directory of your project.

To start the docker-compose.yml with your .env file use this command:

Terminal


docker compose --env-file .env up -d