a6b602d086
When using the 'up' command, only services listed as arguments are attached to, which can be very different to the 'no argument' case if a service has many and deep dependencies: - It's not clear when dependencies have failed to start. Have to run 'compose ps' separately to find out. - It's not clear when dependencies are erroring. Have to run 'compose logs' separately to find out. With a simple setup, it's possible to work around theses issue by using the 'up' command without arguments. But when there are lots of 'top-level' services, with common dependencies, in a single config, using 'up' without arguments isn't practical due to resource limits and the sheer volume of output from other services. This introduces a new '--attach-dependencies' flag to optionally attach dependent containers as part of the 'up' command. This makes their logs visible in the output, alongside the listed services. It also means we benefit from the '--abort-on-container-exit' behaviour when dependencies fail to start, giving more visibility of the failure. Signed-off-by: Ben Thorner <ben.thorner@digital.cabinet-office.gov.uk>
Docker Compose
❗ The docker-compose project announces that as Python 2 reaches it's EOL, versions 1.25.x will be the last to support it. For more information, please refer to this issue.
Compose is a tool for defining and running multi-container Docker applications. With Compose, you use a Compose file to configure your application's services. Then, using a single command, you create and start all the services from your configuration. To learn more about all the features of Compose see the list of features.
Compose is great for development, testing, and staging environments, as well as CI workflows. You can learn more about each case in Common Use Cases.
Using Compose is basically a three-step process.
- Define your app's environment with a
Dockerfileso it can be reproduced anywhere. - Define the services that make up your app in
docker-compose.ymlso they can be run together in an isolated environment. - Lastly, run
docker-compose upand Compose will start and run your entire app.
A docker-compose.yml looks like this:
version: '2'
services:
web:
build: .
ports:
- "5000:5000"
volumes:
- .:/code
redis:
image: redis
For more information about the Compose file, see the Compose file reference.
Compose has commands for managing the whole lifecycle of your application:
- Start, stop and rebuild services
- View the status of running services
- Stream the log output of running services
- Run a one-off command on a service
Installation and documentation
- Full documentation is available on Docker's website.
- Code repository for Compose is on GitHub.
- If you find any problems please fill out an issue. Thank you!
Contributing
Want to help build Compose? Check out our contributing documentation.
Releasing
Releases are built by maintainers, following an outline of the release process.