Using Compose in Production

Using Compose in production

When you define your app with Compose in development, you can use this definition to run your application in different environments such as CI, staging, and production.

The easiest way to deploy an application is to run it on a single server, similar to how you would run your development environment. If you want to scale up your application, you can run Compose apps on a Swarm cluster.

Modify your Compose file for production

You’ll almost certainly want to make changes to your app configuration that are more appropriate to a live environment. These changes may include:

• Removing any volume bindings for application code, so that code stays inside the container and can’t be changed from outside
• Binding to different ports on the host
• Setting environment variables differently (e.g., to decrease the verbosity of logging, or to enable email sending)
• Specifying a restart policy (e.g., restart: always) to avoid downtime
• Adding extra services (e.g., a log aggregator)

For this reason, you’ll probably want to define an additional Compose file, say production.yml, which specifies production-appropriate configuration. This configuration file only needs to include the changes you’d like to make from the original Compose file. The additional Compose file can be applied over the original docker-compose.yml to create a new configuration.

Once you’ve got a second configuration file, tell Compose to use it with the -f option:

$ docker-compose -f docker-compose.yml -f production.yml up -d

See Using multiple compose files for a more complete example.

Deploying changes

When you make changes to your app code, you’ll need to rebuild your image and recreate your app’s containers. To redeploy a service called web, you would use:

$ docker-compose build web
$ docker-compose up --no-deps -d web

This will first rebuild the image for web and then stop, destroy, and recreate just the web service. The --no-deps flag prevents Compose from also recreating any services which web depends on.

Running Compose on a single server

You can use Compose to deploy an app to a remote Docker host by setting the DOCKER_HOST, DOCKER_TLS_VERIFY, and DOCKER_CERT_PATH environment variables appropriately. For tasks like this, Docker Machine makes managing local and remote Docker hosts very easy, and is recommended even if you’re not deploying remotely.

Once you’ve set up your environment variables, all the normal docker-compose commands will work with no further configuration.

Running Compose on a Swarm cluster

Docker Swarm, a Docker-native clustering system, exposes the same API as a single Docker host, which means you can use Compose against a Swarm instance and run your apps across multiple hosts.

Read more about the Compose/Swarm integration in the integration guide.

Compose documentation

• Installing Compose
• Command line reference
• Compose file reference