IIUC, you say Docker is a step backward from both Chef&#x2F;Puppet and Heroku buildpacks. Why do you think it&#x27;s a step backward from Heroku buildpacks? Because a Docker image is the whole userland, whereas Heroku buildpacks deliver application slugs that run on a base maintained by the platform? I see a couple of problems with the Heroku buildpack approach:<p>1. Because buildpacks don&#x27;t run as root, they can&#x27;t take advantage of apt and the whole universe of Debian&#x2F;Ubuntu packages. So it&#x27;s common to see buildpacks pulling binary tarballs from S3 and dropping them into the slug. <i>That</i> is a step backward to me.<p>2. The set of packages in the base platform, at least for the Heroku Cedar stack, is very ad-hoc. I get the impression that it was largely based on what was needed to get Ruby and common gems to work.