You don't need to port Dockerfiles to anything actually if you don't want! rkt supports running Docker images, so you can keep using your Dockerfiles and the Do

You don't need to port Dockerfiles to anything actually if you don't want! rkt supports running Docker images, so you can keep using your Dockerfiles and the Docker build system if you wish. However, you can build rkt images (ACIs) from scratch using any build system you like if you still wish (as detailed in the blog post).