Build Multi-Arch Images with buildx
Use docker buildx with linux/amd64 and linux/arm64 platforms so the image runs on both Intel nodes and Graviton instances.
Task
Configure docker buildx build --platform linux/amd64,linux/arm64 -t app:multi --push . so the cluster enforces the policy at admission time instead of relying on manual review.
When to use this
A developer deploys a pod without docker buildx build --platform linux/amd64,linux/arm64 -t app:multi --push . and it disrupts a node, causing evictions on a production cluster.
Prerequisites
- A Kubernetes cluster with kubectl access
- Cluster admin or namespace edit RBAC
Steps
1. Configure docker buildx build --platform linux/amd64,linux/arm64 -t app:multi --push . in the project configuration file with the recommended defaults.
docker buildx build --platform linux/amd64,linux/arm64 -t app:multi --push .
Expected output: The configuration is accepted and docker buildx build --platform linux/amd64,linux/arm64 -t app:multi --push . runs without errors on the first invocation.
2. Run the check locally to verify docker buildx build --platform linux/amd64,linux/arm64 -t app:multi --push . produces the expected result before pushing.
pnpm test
Expected output: Local run matches CI behavior; no surprises after push.
3. Add the gate to the CI pipeline so docker buildx build --platform linux/amd64,linux/arm64 -t app:multi --push . blocks merge on failure.
- name: Run add multi arch image build
run: pnpm test
Expected output: Pull requests with failing docker buildx build --platform linux/amd64,linux/arm64 -t app:multi --push . are blocked from merging.
Troubleshooting
Problem
The check passes locally but fails in CI
Solution
Pin dependency versions and the runtime to match CI exactly; reproduce with the same Docker image or act.
Problem
Configuration is rejected with a schema error
Solution
Check the tool version matches the config schema; older versions may not support newer fields.
Limitations
- The gate only runs on events that trigger the workflow; locally pushed commits bypass it.
- Configuration drift is possible if someone edits settings outside version control.
Enforce at admission
Start by measuring the problem. Use docker buildx with linux/amd64 and linux/arm64 platforms so the image runs on both Intel nodes and Graviton instances. The most common mistake is adding the gate without first confirming it catches the issue you care about. Run docker buildx build –platform linux/amd64,linux/arm64 -t app:multi –push . against the current codebase and inspect the output before wiring it into CI.
docker buildx build --platform linux/amd64,linux/arm64 -t app:multi --push .Verify the policy
Once the gate is in place, make failures actionable. A failing docker buildx build –platform linux/amd64,linux/arm64 -t app:multi –push . should point to the exact file and line, not a generic error. Pin the tool version in the lockfile so a upstream release does not silently change behavior. Review the gate output in every pull request just like a test result.