Support docker-env with cri-o runtime by afbjorklund · Pull Request #22547 · kubernetes/minikube

afbjorklund · 2026-01-25T19:33:18Z

It is very similar to containerd, but with podman for cri-o instead of nerdctl for containerd. Both using ssh sockets.

Deprecate "podman-env", in favor of using "docker-env" with cri-o #15461

There are plenty of refactoring opportunities (this is just copy/paste), for merging the nerdctl and podman support.

make "docker-env" on containerd stable #22509

This will use BuildKit in a podman container, by default:

WARNING: No output specified with docker-container driver. Build result will only remain in the build cache. To push result image into registry use --push or to load image into docker use --load
...
 => => pulling image moby/buildkit:buildx-stable-1
 => => creating container buildx_buildkit_default

To switch to the legacy buildah, use DOCKER_BUILDKIT=0:

DEPRECATED: The legacy builder is deprecated and will be removed in a future release.
            BuildKit is currently disabled; enable it by removing the DOCKER_BUILDKIT=0
            environment-variable.
....

k8s-ci-robot · 2026-01-25T19:33:24Z

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Pull request overview

This PR adds support for using docker-env command with the cri-o runtime, mirroring the existing experimental support for containerd. The implementation uses podman (via podman.socket) for cri-o, similar to how nerdctl is used for containerd, both utilizing SSH sockets for communication.

Changes:

Added startPodmand function to enable podman.socket and configure DOCKER_HOST for cri-o runtime
Extended docker-env command to support cri-o runtime with experimental warning
Removed overly restrictive runtime validation that prevented non-docker/containerd runtimes

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 6 comments.

File	Description
cmd/minikube/cmd/start.go	Added startPodmand function to start podman.socket and configure environment for cri-o runtime support
cmd/minikube/cmd/docker-env.go	Extended runtime support to include cri-o, added conditional logic to call startPodmand for cri-o, and removed restrictive validation

Comments suppressed due to low confidence (1)

cmd/minikube/cmd/docker-env.go:685

The removal of runtime validation for docker and containerd needs to be replaced with appropriate validation. While the function now checks for containerd with Docker driver compatibility at line 682-683, there's no equivalent driver validation for CRIO runtime. According to the PR description and the similar containerd implementation, CRIO should also only be supported with the Docker driver. Consider adding a similar check for CRIO.

func dockerEnvSupported(containerRuntime, driverName string) error {
	// we only support containerd-env on the Docker driver
	if containerRuntime == constants.Containerd && driverName != driver.Docker {
		return fmt.Errorf("the docker-env command only supports the containerd runtime with the docker driver")
	}
	return nil

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afbjorklund · 2026-01-26T20:12:07Z

The test is failing, because the old host key has been stored in the image unfortunately.

TestDockerEnvCrio

error during connect: Get "http://docker.example.com/v1.51/version": command [ssh -l docker -p 32773 -o ConnectTimeout=30 -T -- 127.0.0.1 docker system dial-stdio] has exited with exit status 255, make sure the URL is valid, and Docker 18.09 or later is installed on the remote host: stderr=Host key verification failed.

EDIT: No idea why it didn't fail for containerd already? Looks the test is missing, for docker-containerd

TestDockerEnvContainerd

afbjorklund · 2026-01-26T21:12:58Z

Aargh, yet another runtime-specific hack:

                        // TODO: refactor to work with docker, temp fix to resolve regression
                        if cr == constants.Containerd {
                                // eventually, run something similar to ssh --append-known
                                appendKnownHelper(nodeName, true)
                        }

It is very similar to containerd, but with podman for cri-o instead of nerdctl for containerd. Both using ssh sockets.

k8s-ci-robot · 2026-01-26T22:40:23Z

@afbjorklund: The following tests failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

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bhavyaBeliever · 2026-01-29T11:29:34Z

+
+	// set up environment variable on remote machine. docker client uses 'non-login & non-interactive shell' therefore the only way is to modify .bashrc file of user 'docker'
+	// insert this at 4th line
+	envSetupCommand := exec.Command("/bin/bash", "-c", "sed -i '4i export DOCKER_HOST=unix:///run/podman/podman.sock' .bashrc")


@afbjorklund This line always adds export DOCKER_HOST=unix:///run/podman/podman.sock in the .bashrc file everytime when minikube docker-env gets executed. Can we check by first by echo $DOCKER_HOST

in the PR #22577 for the function startNerdctld we have implemented the above suggestion.
Link for the implementation: link

Yeah. as I mentioned it was just copied. Probably would be a good thing to refactor these helpers

k8s-ci-robot requested review from ComradeProgrammer and medyagh January 25, 2026 19:33

k8s-ci-robot added size/M Denotes a PR that changes 30-99 lines, ignoring generated files. cncf-cla: yes Indicates the PR's author has signed the CNCF CLA. labels Jan 25, 2026

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medyagh added the ok-to-extra-test test extra environments label Jan 25, 2026

This was referenced Jan 25, 2026

Allow nerdctld on any driver #22549

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make "docker-env" on containerd stable #22509

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Deprecate podman-env, use docker-env instead #22552

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medyagh reviewed Jan 25, 2026

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Comment thread cmd/minikube/cmd/docker-env.go

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afbjorklund force-pushed the docker-env-podman-crio branch 2 times, most recently from 124dcfd to cebcabb Compare January 26, 2026 16:45

k8s-ci-robot added size/L Denotes a PR that changes 100-499 lines, ignoring generated files. and removed size/M Denotes a PR that changes 30-99 lines, ignoring generated files. labels Jan 26, 2026

afbjorklund requested a review from medyagh January 26, 2026 16:45

afbjorklund force-pushed the docker-env-podman-crio branch from cebcabb to 84f0cc1 Compare January 26, 2026 17:29

afbjorklund force-pushed the docker-env-podman-crio branch from 84f0cc1 to 0248b15 Compare January 26, 2026 21:15

Support docker-env with cri-o runtime

c3edc50

It is very similar to containerd, but with podman for cri-o instead of nerdctl for containerd. Both using ssh sockets.

afbjorklund force-pushed the docker-env-podman-crio branch from 0248b15 to c3edc50 Compare January 26, 2026 21:39

bhavyaBeliever reviewed Jan 29, 2026

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bhavyaBeliever mentioned this pull request Feb 20, 2026

docker-env: change --ssh-host login as root #22577

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Support docker-env with cri-o runtime#22547

Support docker-env with cri-o runtime#22547
afbjorklund wants to merge 1 commit intokubernetes:masterfrom
afbjorklund:docker-env-podman-crio

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