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Using Compose in production
While Compose is not yet considered production-ready, if you'd like to experiment and learn more about using it in production deployments, this guide can help. The project is actively working towards becoming production-ready; to learn more about the progress being made, check out the roadmap for details on how it's coming along and what still needs to be done.
When deploying to 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 a separate Compose file, say
production.yml, which specifies production-appropriate configuration.
Note: The extends keyword is useful for maintaining multiple Compose files which re-use common services without having to manually copy and paste.
Once you've got an alternate configuration file, make Compose use it
by setting the COMPOSE_FILE environment variable:
$ COMPOSE_FILE=production.yml
$ docker-compose up -d
Note: You can also use the file for a one-off command without setting an environment variable. You do this by passing the
-fflag, e.g.,docker-compose -f production.yml up -d.
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.
Compose/Swarm integration is still in the experimental stage, and Swarm is still in beta, but if you'd like to explore and experiment, check out the integration guide.