fix(backend): enable multi-arch (amd64, arm64) builds for KFP images. Fixes #12705

[ShreyasN707]

This PR enables multi-architecture (linux/amd64 + linux/arm64) support for Kubeflow Pipelines (KFP) container images so they can run correctly on ARM64 clusters (e.g., Apple Silicon, AWS Graviton, Ampere) without exec format error.

What was changed

1. CI: Enable multi-arch image builds

   Updated ```.github/workflows/build-and-push.yml ```to:

   Add docker/setup-qemu-action@v3 to enable cross-architecture emulation

   Use docker/setup-buildx-action and docker/build-push-action@v6

   Build and push images with:

   platforms:``` linux/amd64,linux/arm64```

This publishes each kfp-* image as a multi-arch manifest list so Kubernetes automatically pulls the correct image for the node architecture.

2. Fix architecture-specific binaries in Dockerfiles

Some KFP images download prebuilt binaries that were hardcoded to amd64. These were updated to be architecture-aware using TARGETARCH.

• proxy/Dockerfile

kubectl is now downloaded from:

linux/${TARGETARCH}/kubectl

• backend/Dockerfile.visualization

• Google Cloud SDK tarball is selected based on:

• amd64 → x86_64

• arm64 → arm

Go-based images (e.g., persistenceagent, scheduledworkflow, etc.) already build cleanly on multi-arch base images and did not require changes.

How to verify :

After CI runs, the images should be published as multi-arch OCI manifests.
This can be verified with:

docker buildx imagetools inspect ghcr.io/kubeflow/kfp-api-server:<tag>

Expected output should list:

Platform: linux/amd64
Platform: linux/arm64

This allows Kubeflow Pipelines to run successfully on ARM64 Kubernetes clusters without exec format error.

Fixes #12705.

[google-oss-prow]

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Details

Needs approval from an approver in each of these files:

• .github/OWNERS
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[google-oss-prow]

Hi @ShreyasN707. Thanks for your PR.

I'm waiting for a kubeflow member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

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[github-actions]

🎉 Welcome to the Kubeflow Pipelines repo! 🎉

Thanks for opening your first PR! We're excited to have you onboard 🚀

Next steps:

• Check out the Contributing Guide for repo-specific guidelines and the Kubeflow Contributor Guide for general community standards
• Join our #kubeflow-pipelines Slack channel
• Attend the Kubeflow Pipelines WG meetings

Feel free to ask questions in the comments.