How Compose works

With Docker Compose you use a YAML configuration file, known as the Compose file, to configure your application’s services, and then you create and start all the services from your configuration with the Compose CLI.

The Compose file, or compose.yaml file, follows the rules provided by the Compose Specification in how to define multi-container applications. This is the Docker Compose implementation of the formal Compose Specification.

The Compose application model#

Computing components of an application are defined as services. A service is an abstract concept implemented on platforms by running the same container image, and configuration, one or more times.

Services communicate with each other through networks. In the Compose Specification, a network is a platform capability abstraction to establish an IP route between containers within services connected together.

Services store and share persistent data into volumes. The Specification describes such a persistent data as a high-level filesystem mount with global options.

The Compose file#

The default path for a Compose file is compose.yaml (preferred) or compose.yml that is placed in the working directory. Compose also supports docker-compose.yaml and docker-compose.yml for backwards compatibility of earlier versions. If both files exist, Compose prefers the canonical compose.yaml.

CLI#

The Docker CLI lets you interact with your Docker Compose applications through the docker compose command and its subcommands. If you're using Docker Desktop, the Docker Compose CLI is included by default.

Using the CLI, you can manage the lifecycle of your multi-container applications defined in the compose.yaml file. The CLI commands enable you to start, stop, and configure your applications effortlessly.

Key commands#

To start all the services defined in your compose.yaml file:

$ docker compose up

To stop and remove the running services:

$ docker compose down 

If you want to monitor the output of your running containers and debug issues, you can view the logs with:

$ docker compose logs

To list all the services along with their current status:

$ docker compose ps