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Docker Compose Commands

Introduction​

Docker Compose is a powerful tool that allows you to define and manage multi-container Docker applications. Instead of using multiple Docker commands to create, start, and connect containers, Docker Compose enables you to use a single YAML file to configure your application's services and execute a single command to create and start all the services.

This guide covers the essential Docker Compose commands you'll need to work with multi-container applications effectively. By the end, you'll be comfortable creating, running, and managing complex Docker environments.

Getting Started with Docker Compose​

Before diving into the commands, make sure you have Docker and Docker Compose installed on your system. You can check your installations with:

bash
docker --version
docker-compose --version

A Docker Compose file (typically named docker-compose.yml) defines the services, networks, and volumes for your application. Here's a simple example:

yaml
version: '3'
services:
  web:
    image: nginx:latest
    ports:
      - "8080:80"
  database:
    image: mysql:5.7
    environment:
      MYSQL_ROOT_PASSWORD: example

This file defines two services: a web server using the Nginx image and a database using MySQL.

Essential Docker Compose Commands​

1. Creating and Starting Containers​

docker-compose up​

This command builds, creates, and starts all services defined in your docker-compose.yml file.

bash
# Start all services
docker-compose up

# Start in detached mode (background)
docker-compose up -d

# Build images before starting containers
docker-compose up --build

Output example:

Creating network "myapp_default" with the default driver
Creating myapp_database_1 ... done
Creating myapp_web_1      ... done
Attaching to myapp_database_1, myapp_web_1
database_1  | 2023-04-10T10:15:23.334Z [Note] [Entrypoint]: Entrypoint script for MySQL Server started.
web_1       | /docker-entrypoint.sh: /docker-entrypoint.d/ is not empty, will attempt to perform configuration

2. Stopping Containers​

docker-compose down​

This command stops and removes all containers, networks, and volumes defined in the Docker Compose file.

bash
# Stop and remove containers, networks
docker-compose down

# Additionally remove volumes
docker-compose down --volumes

# Additionally remove images
docker-compose down --rmi all

docker-compose stop​

This command stops running containers without removing them.

bash
# Stop all services
docker-compose stop

# Stop specific service
docker-compose stop web

3. Viewing Container Status​

docker-compose ps​

This command lists all containers related to the services defined in your Docker Compose file and their status.

bash
docker-compose ps

Output example:

       Name                     Command               State           Ports
----------------------------------------------------------------------------------
myapp_database_1    docker-entrypoint.sh mysqld      Up      3306/tcp, 33060/tcp
myapp_web_1         /docker-entrypoint.sh ngin ...   Up      0.0.0.0:8080->80/tcp

4. Viewing Logs​

docker-compose logs​

This command displays log outputs from services.

bash
# View logs of all services
docker-compose logs

# View logs of a specific service
docker-compose logs web

# Follow log output
docker-compose logs -f

# Show last 10 lines
docker-compose logs --tail=10

5. Executing Commands in Containers​

docker-compose exec​

This command executes a command in a running container.

bash
# Open a shell in the web service container
docker-compose exec web bash

# Run a specific command
docker-compose exec database mysql -u root -p

6. Building Images​

docker-compose build​

This command builds or rebuilds services defined in the Docker Compose file.

bash
# Build all services
docker-compose build

# Build a specific service
docker-compose build web

# Build with no cache
docker-compose build --no-cache

7. Pulling Images​

docker-compose pull​

This command pulls the latest images for services defined in the Docker Compose file.

bash
# Pull all images
docker-compose pull

# Pull a specific service's image
docker-compose pull database

8. Creating Service Configuration​

docker-compose config​

This command validates and displays the composition file after processing.

bash
# Check if docker-compose.yml is valid
docker-compose config

# Check a specific file
docker-compose -f custom-compose.yml config

9. Scaling Services​

docker-compose up --scale​

This command scales a service to a specified number of instances.

bash
# Scale the web service to 3 instances
docker-compose up -d --scale web=3

Output example:

Creating myapp_web_1 ... done
Creating myapp_web_2 ... done
Creating myapp_web_3 ... done

Practical Examples​

Example 1: Setting Up a Web Application with Database​

Let's create a simple web application with a front-end, backend API, and database:

yaml
version: '3'
services:
  frontend:
    image: node:14
    working_dir: /app
    volumes:
      - ./frontend:/app
    command: npm start
    ports:
      - "3000:3000"
    depends_on:
      - api

  api:
    image: node:14
    working_dir: /app
    volumes:
      - ./api:/app
    command: npm start
    ports:
      - "4000:4000"
    depends_on:
      - db
    environment:
      - DB_HOST=db
      - DB_USER=root
      - DB_PASSWORD=example
      - DB_NAME=myapp

  db:
    image: mysql:5.7
    ports:
      - "3306:3306"
    environment:
      - MYSQL_ROOT_PASSWORD=example
      - MYSQL_DATABASE=myapp
    volumes:
      - db-data:/var/lib/mysql

volumes:
  db-data:

To set up and run this application:

bash
# Start all services in detached mode
docker-compose up -d

# Check status
docker-compose ps

# View API logs
docker-compose logs api

# Execute MySQL command
docker-compose exec db mysql -u root -p -e "SHOW DATABASES;"

Example 2: Development vs. Production Configuration​

You can use multiple compose files for different environments:

docker-compose.yml (base configuration):

yaml
version: '3'
services:
  app:
    build: .
    ports:
      - "8000:8000"
  db:
    image: postgres:13
    volumes:
      - db-data:/var/lib/postgresql/data

volumes:
  db-data:

docker-compose.override.yml (development overrides, applied automatically):

yaml
version: '3'
services:
  app:
    volumes:
      - ./app:/app
    environment:
      - DEBUG=true
  db:
    ports:
      - "5432:5432"

docker-compose.prod.yml (production overrides):

yaml
version: '3'
services:
  app:
    environment:
      - DEBUG=false
    restart: always
  db:
    restart: always

To use these configurations:

bash
# For development (uses docker-compose.yml + docker-compose.override.yml automatically)
docker-compose up -d

# For production (specify both files)
docker-compose -f docker-compose.yml -f docker-compose.prod.yml up -d

Docker Compose Command Flow​

Here's a typical workflow with Docker Compose:

Summary​

Docker Compose provides a streamlined way to manage multi-container applications through a single YAML file and simple commands. The key commands we've covered are:

  • docker-compose up: Create and start containers
  • docker-compose down: Stop and remove containers
  • docker-compose ps: View container status
  • docker-compose logs: View logs
  • docker-compose exec: Execute commands in containers
  • docker-compose build: Build or rebuild services
  • docker-compose pull: Pull service images
  • docker-compose config: Validate configuration
  • docker-compose up --scale: Scale services

By mastering these commands, you'll be able to efficiently develop, test, and deploy complex applications using Docker Compose.

Additional Resources​

Exercises​

  1. Create a docker-compose.yml file that runs a WordPress site with a MySQL database.
  2. Modify an existing Docker Compose file to scale a service to multiple instances.
  3. Create separate development and production Docker Compose configurations for an application.
  4. Set up a multi-container application with proper dependency order and networking.
  5. Use Docker Compose to set up a local development environment for a web application with frontend, backend, and database components.

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