How to publish docker multi-arch images with Pipeline runtime v3

[Antoine]

Hello,

I was very excited about the Pipeline runtime v3 release and wanted to use it for publishing multi-arch docker images using it.

I followed your documentation, to build images for platforms linux/amd64 and linux/arm64. They are built correctly. However, I'm not able to list them with `docker image ls --tree` nor publishing them in a separate step.

I followed your instructions by first creating an image with docker-cli, compose and buildx preinstalled and then defining a pipeline custom trigger to build the docker multi-arch image as described in 'Multi -arch Build' section.

The build produces this warning message:

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

Is there a way with bitbucket pipeline runtime v3 to list and publish multi-arch docker images after the build step?

Thank you very much for your help!

[Mark C]

Hi @Antoine

Welcome to the community.

Could you please share your YAML config for us to check? Please mask any sensitive information before sharing it

Regards,
Mark C

[Antoine]

Hello @Mark C 

Thank you for your support.

I used the config given in the documentation

options:
  runtime:
    cloud:
      version: "3"
pipelines:
  custom:
    multi-arch-build:
      - step:
          image: "<my-image-with-docker-cli-and-buildx>"
          services:
            - docker
          script
            - docker buildx create --name multiarch-builder --driver docker-container --use
            - docker buildx inspect --bootstrap
            - docker run --rm --privileged tonistiigi/binfmt --install all
            - docker buildx build -t test:local --platform=linux/amd64,linux/arm64 .
            - docker image ls --tree # won't return any image
            - docker image push test:local # fails

I added some comments with problematic steps

[Antoine]

Hello @Mark C 

Were you able to look into the issue? 

Thank you for your help!

Best regards,

Antoine

[Ben]

Hi @Antoine 

Apologies for the delay - I have taken a look into this in Marks absence.

When using docker buildx build with the docker-container driver, the built image is not automatically loaded into the local Docker image store. Instead, it stays in the BuildKit cache unless you specify an output option - hence why you receive the error:

• --push to push the image directly to a registry.

• --load to load the image into the local Docker daemon (only works for single-platform builds).

Docker image ls shows nothing as the image is not available locally because it was never loaded (--load) or pushed (--push). That's why docker image ls --tree returns nothing, and docker image push test:local fails—there's no local image to push

Please modify your YAML config to the following and let me know if it's successful:

script:
   - docker login -u $DOCKER_USER -p $DOCKER_PASS <your-registry>
   - docker buildx create --name multiarch-builder --driver docker-container --use
   - docker buildx inspect --bootstrap
   - docker run --rm --privileged tonistiigi/binfmt --install all
   - docker buildx build -t <your-registry>/<your-image>:<tag> --platform=linux/amd64,linux/arm64 --push .

If you're still encountering issues - please raise a ticket directly with our support team using your paid workspace URL to ensure you receive timely responses according to our SLA. Raising a formal ticket will allow us to gain access to your workspace to check your YAML config/build logs in detail:

• https://support.atlassian.com/

If you have issues raising a ticket - please let me know your timezone and I will raise one on your behalf with the relevant team in your region.

Cheers!

- Ben (Bitbucket Cloud Support)

[Antoine]

Hello @Ben 

Thanks a lot for your support and all the explanations!

Thing is we have internal tooling I would like to reuse for multi-arch builds. This imposes to push images in a separate step and not during the build step. 

From what I understand from docker doc it would help having access to containerd which is able to store multi-arch images. Do you know if that's possible with the new pipeline runtime v3?

Thank you!

Antoine

[Mark C]

Hi @Antoine

Apologies for the late response here.

What you can do is to use --load flag in the buildx command if you'd like to access the built container within the same step.

Regards,
Mark C