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Show HN: Unregistry – “docker push” directly to servers without a registry

(github.com)
726 points psviderski | 3 comments | 18 Jun 25 23:17 UTC | HN request time: 0.463s | source

I got tired of the push-to-registry/pull-from-registry dance every time I needed to deploy a Docker image.

In certain cases, using a full-fledged external (or even local) registry is annoying overhead. And if you think about it, there's already a form of registry present on any of your Docker-enabled hosts — the Docker's own image storage.

So I built Unregistry [1] that exposes Docker's (containerd) image storage through a standard registry API. It adds a `docker pussh` command that pushes images directly to remote Docker daemons over SSH. It transfers only the missing layers, making it fast and efficient.

  docker pussh myapp:latest user@server
Under the hood, it starts a temporary unregistry container on the remote host, pushes to it through an SSH tunnel, and cleans up when done.

I've built it as a byproduct while working on Uncloud [2], a tool for deploying containers across a network of Docker hosts, and figured it'd be useful as a standalone project.

Would love to hear your thoughts and use cases!

[1]: https://github.com/psviderski/unregistry

[2]: https://github.com/psviderski/uncloud

1. yjftsjthsd-h ◴[19 Jun 25 00:48 UTC] No.44314496[source]▶
What is the container for / what does this do that `docker save some:img | ssh wherever docker load` doesn't? More efficient handling of layers or something?
replies(2): >>44314731 #>>44316100 #
2. psviderski ◴[19 Jun 25 01:44 UTC] No.44314731[source]▶
Yeah exactly, which is crucial for large images if you change only a few last layers.

The unregistry container provides a standard registry API you can pull images from as well. This could be useful in a cluster environment where you upload an image over ssh to one node and then pull it from there to other nodes.

This is what I’m planning to implement for Uncloud. Unregistry is so lightweight so we can embed it in every machine daemon. This will allow machines in the cluster to pull images from each other.

3. pragmatick ◴[19 Jun 25 06:44 UTC] No.44316100[source]▶
Relatively early on the page it says:

"docker save | ssh | docker load transfers the entire image, even if 90% already exists on the server"