To install Docker on Debian: apt-get install docker.io (note it's NOT just "docker", that's an entirely unrelated package)
For other docker images, like infrastructure images, we manage them differently, see: Kubernetes/Images#Image_building
To just test building a random image a http server without state is a good candidate.
Updating an image
Updating CI docker images
When updating CI images followind the documentation on MediaWiki. However the basic process is
- update the changelog of the appropriate image to force a docker image rebuild. You can use docker-pkg (see MediaWiki page above)
- update the image version in the CI job specification
Deleting an image (from registry)
To delete one or more Docker image tags from the WMF docker registry, you may use the tool
docker-registryctl on the current build host. It will do it's best to remove the tags/image from the registry, despite the circumstances.