How do you enable experimental features for Docker on Bitbucket Pipelines?

[Keith Ward]

I want to squash my docker image so that I can remove intermediate containers that contain secrets.  Docker allows you to do this with the squash flag:

 docker build -t $IMAGE_NAME --build-arg SECRET_KEY=$SECRET_KEY --squash .

 The problem is pipelines doesn't have experimental features enabled:

"--squash" is only supported on a Docker daemon with experimental features enabled

 Is there a way to enable these features for Docker in Bitbucket Pipelines?

[Philip Hodder]

Hi Keith,

Currently we do not support having Docker run in experimental mode. You can open a feature request for it to be supported.

The Docker team recommends you use multi-stage builds instead of squash to remove intermediate layers. There have also been some discussions around remove the squash flag too. Multi-stage builds are supported in Pipelines.

Thanks,

Phil