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726 points psviderski | 1 comments | | HN request time: 0.201s | 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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modeless ◴[] No.44314955[source]
It's very silly that Docker didn't work this way to start with. Thank you, it looks cool!
replies(1): >>44315047 #
TheRoque ◴[] No.44315047[source]
You can already achieve the same thing by making your image into an archive, pushing it to your server, and then running it from the archive on your server.

Saving as archive looks like this: `docker save -o may-app.tar my-app:latest`

And loading it looks like this: `docker load -i /path/to/my-app.tar`

Using a tool like ansible, you can achieve easily what "Unregistry" is doing automatically. According to the github repo, save/load has the drawback of tranfering the whole image over the network, which could be an issue that's true. And managing the images instead of archive files seems more convenient.

replies(3): >>44315094 #>>44316773 #>>44324210 #
1. authorfly ◴[] No.44316773[source]
Good advice and beware the difference between docker export (which will fail if you lack enough storage, since it saves volumes) and docker save. Running the wrong command might knock out your only running docker server into an unrecoverable state...