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

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726 points psviderski | 1 comments | 18 Jun 25 23:17 UTC | HN request time: 0.206s | 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

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czhu12 ◴[19 Jun 25 04:13 UTC] No.44315367[source]▶
Does this work with Kubernetes image pulls?
replies(1): >>44315770 #
1. psviderski ◴[19 Jun 25 05:36 UTC] No.44315770[source]▶
I guess you're asking about the registry part (not 'pussh' command). It exposes the containerd image store as standard registry API so you can use any tools that work with regular registry to pull/push images to it.

You should be able to run unregistry as a standalone service on one of the nodes. Kubernetes uses containerd for storing images on nodes. So unregistry will expose the node's images as a registry. Then you should be able to run k8s deployments using 'unregistry.NAMESPACE:5000/image-name:tag' image. kubelets on other nodes will be pulling the image from unregistry.

You may want to take a look at https://spegel.dev/ which works similarly but was created specifically for Kubernetes.