[cookiecaper]

Thanks for this post. It does indeed answer most of my follow-up questions.

I wanted to let you know that I gave `docker build --squash` a try today. This is the output I got:

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

so that feature is not yet mainlined.

Also, I encountered another issue today when trying to do a `docker push`. It retried a cache layer multiple times before conceding with `open /dev/mapper/docker-254:0-xxx-yyy-zzz: no such file or directory` on one of the layers. I had to rebuild the image with `--no-cache` to get it to push.

Not doing anything unusual/fancy, just an ordinary docker push, which worked fine on other images before and after. No auto-cleanup scripts running in the background or anything that should cause a layer to go mysteriously missing.