Distribution: Registries & Air Gaps

The Registry Is the Deployment Contract

CI produces images; environments consume them. The registry between them is the single source of truth - run your own in one command when needed:

$ docker run -d --name registry -p 5000:5000 registry:2
$ docker tag app:1.4 localhost:5000/app:1.4
$ docker push localhost:5000/app:1.4
$ curl http://localhost:5000/v2/_catalog        # the registry HTTP API

(Production registries add TLS + auth: Harbor, ECR, GHCR, Artifactory…)

No network? Images still move. save/load turns an image into a portable tarball - the delivery mechanism for air-gapped sites, ships, factory floors:

$ docker save -o sensor-agent.tar sensor-agent:3.2     # sending side
$ docker load -i sensor-agent.tar                      # receiving side

	`save`/`load`	`export`/`import`
Operates on	images (all layers, tags, history)	a container's flattened filesystem
Use for	moving images between daemons	snapshotting a container as a new base

Goal: Both halves are labs: Private Registry (run, tag, push, verify via the API) and Air-Gap Transfer (save → remove → load, proving the round trip).