docs/scratch

FROM scratch

This image is most useful in the context of building base images (such as debian and busybox) or super minimal images (that contain only a single binary and whatever it requires, such as hello-world).

As of Docker 1.5.0 (specifically, docker/docker#8827), FROM scratch is a no-op in the Dockerfile, and will not create an extra layer in your image (so a previously 2-layer image will be a 1-layer image instead).

From https://docs.docker.com/engine/userguide/eng-image/baseimages/:

You can use Docker’s reserved, minimal image, scratch, as a starting point for building containers. Using the scratch “image” signals to the build process that you want the next command in the Dockerfile to be the first filesystem layer in your image.

While scratch appears in Docker’s repository on the hub, you can’t pull it, run it, or tag any image with the name scratch. Instead, you can refer to it in your Dockerfile. For example, to create a minimal container using scratch:

FROM scratch
COPY hello /
CMD ["/hello"]