--src-daemon-host does not work with SSH based docker daemon

[abdennour]

Docker supports 3 ways to connect to its damon:

1. Famous: /var/run/docker.sock
2. TCP thru env var DOCKER_HOST
3. SSH thru docker contexts & DOCKER_CONTEXT env var.

The current skoepo supports (1) and (2).. However no way to let it work with (3).

My docker context ls shows something like the following:

NAME          DESCRIPTION                               DOCKER ENDPOINT               KUBERNETES ENDPOINT                    ORCHESTRATOR
default       Current DOCKER_HOST  unix:///var/run/docker.sock                                               (default)   swarm
dev *                                                      ssh://[email protected]

As demonstrated, the current context is the one which had * .. in my example, it's dev.

Now trying to use skopeo with that context:

skopeo copy --src-daemon-host=ssh://[email protected]  ....

But unfortunately, skopeo consider it as https :(

FATA[0000] Error initializing source docker-daemon:testdebug-mini_app:latest: 
Error loading image from docker engine: error during connect: 
Get  https://user%4010.x.y.z/v1.22/images/get?names=testdebug-mini_app%3Alatest"

Any solution ? any workaround to let it work ?

[mtrmac]

Thanks for your report.

It seems that this is a feature specific to the Docker CLI, not to the provided client libraries (in https://github.com/docker/cli/blob/ab794859fe792cc4b6d1632b919b775613bc17fc/cli/connhelper/connhelper.go#L43 ); so that would not be available in Skopeo right now.

From a quick look it doesn’t seem trivially possible to emulate that (the ssh command could be run manually, but the docker-daemon: client expects to connect to a socket, so there would need to be a local socket server). Maybe some combination of nc and ssh could work, I didn’t look in to this further right now.

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[swarren]

Presumably this could be emulated via ssh -R or ssh -L; this is exactly what I'm doing manually in issue 2017.

[github-actions]

A friendly reminder that this issue had no activity for 30 days.