Something happened a little while ago which we did not have time to commensurate properly. Our Rocker image for R is now the official R image for Docker itself. So getting R (via Docker) is now as simple as saying docker pull r-base.
This particular container is essentially just the standard r-base Debian package for R (which is one of a few I maintain there) plus a mininal set of extras. This r-base forms the basis of our other containers as e.g. the rather popular r-studio container wrapping the excellent RStudio Server.
A lot of work went into this. Carl and I also got a tremendous amount of help from the good folks at Docker. Details are as always at the Rocker repo at GitHub.
Docker itself continues to make great strides, and it has been great fun help to help along. With this post I achieved another goal: blog about Docker with an image not containing shipping containers. Just kidding.