mindthegap

README

Mind The Gap

mindthegap provides utilities to manage air-gapped image bundles, both creating image bundles and seeding images from a bundle into an existing image registry.

Usage

Creating an image bundle

mindthegap create image-bundle --images-file <path/to/images.yaml> \
  --platform <platform> [--platform <platform> ...] \
  --output-file <path/to/output.tar>

See the example images.yaml for the structure of the images config file.

Platform can be specified multiple times. Supported platforms:

linux/amd64
linux/arm64
windows/amd64
windows/arm64

All images in the images config file must support all the requested platforms.

The output file will be a tarball that can be seeded into a registry, or that can be untarred and used as the storage directory for a Docker registry served via registry:2.

Pushing an image bundle

mindthegap push image-bundle --image-bundle <path/to/images.tar> \
  --to-registry <registry.address> \
  [--to-registry-insecure-skip-tls-verify]

All images in the image bundle tar file will be pushed to the target docker registry.

Serving an image bundle

mindthegap serve image-bundle --image-bundle <path/to/images.tar> \
  [--listen-address <listen.address>] \
  [--listen-port <listen.port>]

Start a Docker registry serving the contents of the image bundle. Note that he Docker registry will be in read-only mode to reflect the source of the data being a static tarball so pushes to this registry will fail.

How does it work?

mindthegap starts up a Docker registry and then uses skopeo to copy the specified images for all specified platforms into the running registry. The resulting registry storage is then tarred up, resulting in a tarball of the specified images.

The resulting tarball can be loaded into a running Docker registry, or be used as the initial storage for running your own registry from via Docker or in a Kubernetes cluster.

Building

Prerequisite: set up git lfs

mindthegap embeds a static build of skopeo. In order to make keep the repo clean, the static builds of skopeo are added via git lfs. If you haven't previously set up git lfs on your machine (don't worry, it's just a case of install git-lfs and running git lfs install), then follow the instructions on the git lfs site.

Building the CLI

Build the CLI using make build-snapshot that will output binary into dist/mindthegap_$(GOOS)_$(GOARCH)/mindthegap and put it in $PATH.