{"id":135623,"date":"2025-10-21T07:50:24","date_gmt":"2025-10-21T07:50:24","guid":{"rendered":"\/tutorials\/?p=135623"},"modified":"2026-06-11T03:46:40","modified_gmt":"2026-06-11T03:46:40","slug":"what-is-docker-compose","status":"publish","type":"post","link":"\/ca\/tutorials\/what-is-docker-compose\/","title":{"rendered":"What is Docker Compose, and how to use it"},"content":{"rendered":"

Docker Compose<\/strong> is a tool designed for defining and running multi-container projects. Developers use it to simplify the management of interconnected services, such as combining a front-end application and a database server, allowing them to administer the entire application stack easily.<\/p>

By using a single YAML file<\/strong>, Docker Compose enables developers to specify the necessary infrastructure for building an application, including the image to use, the internal network setup, and the persistent volume to mount. Then, you can build all the containers based on the configuration by running the docker compose up<\/strong> command.<\/p>

Throughout the project lifecycle, you can manage containers using other Compose commands. For example, docker compose down<\/strong> tears down all the services, while docker compose ps<\/strong> lists currently running containers specified within the YAML file.<\/p>

To use Docker Compose, you must have Docker Engine and Docker CLI installed. Then, configure it by downloading the plugin using your system’s package manager or Homebrew. If you use Docker Desktop, this orchestration tool is pre-packaged out of the box.<\/p>

Dive deeper to learn more about what Docker Compose is and how to use it to manage multi-container applications.<\/p>

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What is Docker Compose?<\/strong><\/h2>

Docker Compose is a tool that enables developers to easily define and run multi-container Docker applications. Its primary purpose is to simplify, centralize, and unify the management of multiple services.<\/p>

Docker Compose relies on a single YAML file where you define everything about the containers in your application: which image each service should use, how they communicate, and where they store persistent data. This configuration enables you to build and manage these containers.<\/p>

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\n Learn about Docker image vs container 🐳 <\/p>\n <\/div>\n

Docker Compose ties closely with other important Docker concepts, such as images and containers. If you are unfamiliar with these, we recommend checking out our tutorial to learn more about the difference between a Docker image and a container<\/a>.<\/p>\n <\/div>\n \n\n\n\n<\/p>

How does Docker Compose work?<\/strong><\/h2>

Docker Compose works by defining three core components of multi-container applications in the YAML file: services<\/strong>, networks<\/strong>, and volumes<\/strong>.<\/p>

When you deploy an app from the YAML file, Docker Compose will pull or build the image to create that service<\/strong>, also known as a container.<\/p>

Docker Compose then creates an internal network to enable services to communicate with one another and initializes volumes to store persistent data that the containers can share. It also sets up the environment variables for each service to pass data without directly hardcoding them into its image.<\/p>

All configurations – including which image to use, how to set up the network, where to mount the persistent volumes, and which environment variables to include – are defined in the YAML file. This means you can build and manage all containers of your application from this file.<\/p>

Example of a Docker Compose YAML file<\/strong><\/h3>

Here’s an example of an actual Docker Compose YAML file defining a project comprising two interconnected services: a simple web application and a Redis cache instance.<\/p>

To help you understand the configuration, check the comments to see what each line does. <\/p>

services:\n\n  web: # Service for the web application\n\n    build: . # Builds the image from the Dockerfile in the current directory\n\n    ports:\n\n      - \"8000:5000\" # Maps host port 8000 to container port 5000\n\n    depends_on:\n\n      - redis # Ensures 'redis' starts before 'web' \n\n    volumes:\n\n      - .\/:\/app # Mounts the current directory into the container at \/app (bind mount)\n\n    environment:\n\n      REDIS_HOST: ${REDIS_HOST:-redis} # Sets REDIS_HOST from env or defaults to 'redis'\n\n  redis: # Service for the Redis cache\n\n    image: redis:6 # Uses the official Redis image (version 6)\n\n    expose:\n\n      - \"6379\" # Exposes port 6379 to other services within the Docker network\n\n    volumes:\n\n      - redis_data:\/data # Persists Redis data in a named volume\n\nvolumes:\n\n  redis_data: {} # Declares the named volume for Redis data persistence<\/pre>
Note that depending on your application, services, and configuration, the exact content of the YAML file varies.<\/p>
How to install Docker Compose<\/strong><\/h2>
The steps to install Docker Compose will vary depending on the type of Docker application and your operating system.<\/p>
If you use Docker Desktop<\/strong>, Compose is already pre-configured. For Docker CLI, you can set up the Compose plugin either from the official repository or by downloading it manually. We’ll explain how to do it from the official repository, as this will simplify future updates.<\/p>
Before proceeding, ensure that you’ve configured Docker Engine and Docker CLI. If you haven’t, check out our guide to installing Docker on Ubuntu<\/a> to learn more about the steps.<\/p>
Once you have Engine and CLI set up, install Compose based on your operating system. In Linux, you can do this using your system’s package manager. For example, here are the commands for doing it on Debian-based distributions:<\/p>
sudo apt update<\/pre>
sudo apt install docker-compose-plugin<\/pre>
If you use non-Debian operating systems, simply replace ap<\/strong>t<\/strong> with the corresponding package manager. For instance, use dnf<\/strong> if you run RHEL-based distros.<\/p>
For macOS users, install Docker Compose via Homebrew using this command:<\/p>
brew install docker-compose<\/pre>
On both Linux and macOS, you can check if Docker Compose is successfully installed by running the following command:<\/p>
docker compose version<\/pre>
If Docker Compose is properly configured, you will see its version number on your terminal.<\/p>
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