have podman env or similar command to output setup that makes other docker clients work

[maxandersen]

Is this a BUG REPORT or FEATURE REQUEST? (leave only one on its own line)

/kind feature

Description

I'm coming to podman to have a way to run containers but still use it with the larger ecosystem
that know how to connect to docker demon (i.e. test containers etc.)

They don't "just work" thus I assume there is some environment I need to setup - should/could podman provide a command like podman env that would print out out the necessary config ?

Describe the results you received:

podman env 
DOCKER_HOST=abc
DOCKER_...
## use this in your shell `source <(podman env)`

or similar.

Just some hint/setup to enable docker ce migrations.

[afbjorklund]

It's possible to view the current sockets, using podman system connection ls

Ultimately this needs to be paired with the other feature, to create a ssh tunnel.

But one could add a generic feature. to print both DOCKER_HOST and CONTAINER_HOST ?

At the moment, it outputs JSON: (podman system connection ls --format=json)

[
    {
        "Name": "podman-machine-default*",
        "URI": "ssh://core@localhost:33475/run/user/1000/podman/podman.sock",
        "Identity": "/home/anders/.ssh/podman-machine-default"
    },
    {
        "Name": "podman-machine-default-root",
        "URI": "ssh://root@localhost:33475/run/podman/podman.sock",
        "Identity": "/home/anders/.ssh/podman-machine-default"
    }
]

---

Currently there is no way to provide the ssh key or even the socket path to Docker, though...

stderr=root@localhost: Permission denied (publickey,gssapi-keyex,gssapi-with-mic)

ssh host connection is not valid: extra path after the host: "/run/podman/podman.sock"

So one has to work around it, using ssh-add and using symlinks. Not needed for Podman.

[n1hility]

FYI I have a WIP proposal that introduces this and ssh tunneling here:
#11643

[afbjorklund]

@n1hility : does your PR add another "connection" for the temporary unix socket, or only the env vars ?

I don't have anything against just using the environment variables myself, but they were "replaced" earlier.

I suppose if you only use Docker, you are stuck with DOCKER_HOST (and workarounds for the SSH key)

Then something like docker-machine env work work just fine (for eval), see also minikube docker-env

[github-actions]

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

[rhatdan]

@n1hility @afbjorklund What is going on with this?

[n1hility]

@rhatdan This should be addressed soon as part of the work on #11462

[github-actions]

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

[maxandersen]

Still relevant

[github-actions]

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

[baude]

I'm a little turned around on this one @maxandersen ... what exactly are you asking for? are you wanting to use a podman frontend and a docker backend?

[n1hility]

after chatting with @maxandersen, he would like to also have an additional docker-env command like minikube or the old docker machine in case the output of podman machine start was ran in the background or left running and later forgotten.

[n1hility]

ill do a follow-up PR for that for a later release

[afbjorklund]

Both docker and podman seem to be switching to magic config files, instead of using environment variables.

DOCKER_HOST vs. docker context ls

CONTAINER_HOST vs. podman system connection list

Currently docker does list the environment context, but podman does not list the environment connection.

$ docker context ls
NAME        DESCRIPTION                               DOCKER ENDPOINT                                     KUBERNETES ENDPOINT   ORCHESTRATOR
default *   Current DOCKER_HOST based configuration   unix:///var/run/docker.sock                                               swarm
lima                                                  unix:///home/anders/.lima/docker/sock/docker.sock                         

$ podman system connection list
Name        URI                                                Identity    Default
lima        unix:///home/anders/.lima/podman/sock/podman.sock              false

[afbjorklund]

The help text seems to have a typo/syntax error in it, missing the // in the scheme.

podman --remote --help

--url string URL to access Podman service (CONTAINER_HOST) (default "unix:/run/user/1000/podman/podman.sock")

But it's a valid configuration (for Podman), so it's just not an URL. Probably not important.

[maxandersen]

But magic context files is more for global config, right ?

It doesn't let you isolate / reset configuration for just one shell ?

[afbjorklund]

Right, that is why I don't like them myself...

But podman machine sets it up by default:

Name                         URI                                                          Identity                                  Default
podman-machine-default       ssh://core@localhost:42465/run/user/1000/podman/podman.sock  /home/anders/.ssh/podman-machine-default  true
podman-machine-default-root  ssh://root@localhost:42465/run/podman/podman.sock            /home/anders/.ssh/podman-machine-default  false

No environment variables needed to set.

The default socket changed, everywhere.

podman --remote --help

--url string URL to access Podman service (CONTAINER_HOST) (default "ssh://core@localhost:42465/run/user/1000/podman/podman.sock")

[rhatdan]

We have talked about adding a podman context command to match the Docker one for certain types of scripts. Perhaps hidden from users.

podman machine env would probably be acceptable Perhaps with a --docker option or maybe just print out the DOCKER_HOST=/PATH