Use buildkit with Bitbucket Pipelines runners

[#1]

‘Support buildkit’ has been one of the most requested features in Bitbucket Pipelines for quite some time now (refer to this ticket from our public open issues). With Bitbucket Pipelines runners now released, you can specify your step to use a custom ‘dind’, which allows you to use the supported feature like ‘buildkit’ with Bitbucket Pipelines. Here’s how it works:

Define a custom ‘dind’

First, define a docker service with docker in the docker image (dind). Since the current docker:dind is already enabled in buildkit by default, you can just use it (as shown below):

definitions:
  services:
    docker:
      image: docker:dind

Then in your Pipeline step, there are couple different ways to use buildkit:

Enable buildkit with DOCKER_BUILDKIT env var

pipelines:
  default:
  - step:
      name: Step 1
      runs-on: self.hosted
      script:
        - export DOCKER_BUILDKIT=1
        - docker build .
      services:
        - docker

definitions:
  services:
    docker:
      image: docker:dind

Here is the output:

Interact with BuildKit through docker buildx commands

Unfortunately, Bitbucket Pipelines default build image doesn’t have the buildx plugin installed. So this process is a bit more involved:

Setup custom build image

Install buildx in the build image:

FROM atlassian/default-image:2

COPY --from=docker/buildx-bin /buildx /usr/libexec/docker/cli-plugins/docker-buildx

Then push it to a docker host so runners can use it.

Config Step to use custom build image

pipelines:
  default:
  - step:
      name: Step 1
      image: dockerhub-user-name/test-build-image
      runs-on: self.hosted
      script:
        - docker
        - docker buildx version
        - docker buildx build .
      services:
        - docker
definitions:
  services:
    docker:
      image: docker:dind

Here is the output: