How to use Docker BuildKit for faster builds

· Category: DevOps & Docker

Short answer

Enable BuildKit by setting DOCKER_BUILDKIT=1 to unlock concurrent stage execution, improved caching, and secure secret mounts without baking credentials into layers.

Details

BuildKit is Docker's modern builder backend. In a Dockerfile, use cache mounts to persist package manager data across builds:

RUN --mount=type=cache,target=/root/.cache/pip \
    pip install -r requirements.txt

This dramatically speeds up repeated builds in CI. Because BuildKit supports frontends beyond the classic Dockerfile, learning how to write a Dockerfile with BuildKit-specific syntax pays dividends. You can also mount secrets and SSH agents securely, keeping sensitive files out of the final image. For organizations building Docker images at scale, BuildKit combined with remote cache registries cuts pipeline times by 50% or more.

Tips

  • Use --cache-from in CI to import previous build caches from a registry.
  • Enable garbage collection on the BuildKit daemon to reclaim disk from abandoned caches.
  • Keep Dockerfiles deterministic; non-reproducible steps break cache efficiency.