Deis
lastmod 2018-09-05created 2018-09-051 edits
If Docker is the bottom of the pyramid, CoreOS is the middle and Deis is the top. Developers can easily build a Heroku-style PaaS from open-source components. Anything that can be put into a Docker container can be deployed. The same is true of existing Heroku.
The whole package can be built from the components mentioned above. Docker for the container structure, CoreOS as the OS layer, and Deis are all based on Go (the API server uses some Python).