Root ubuntu docker images should be "unminimized"

The root docker containers for ubuntu are based on the official ubuntu docker containers (FROM ubuntu:20.04) and these are “minimized” for non-login use, as explained in the ubuntu wiki under “Minimal”.

The root docker containers are obviously for login use, and thus they should be “unminimized” during the container build, e.g. by adding a “yes | unminimize” invocation in the dockerfile. Some consequences are missing man pages and inconsistent locale settings.

At the moment we fix this post-mortem in our local containers derived from the root-ubuntu docker containers, but this fix should be done at the source so that the root-ubuntu docker containers are ready for use.

Hi @skluth,
welcome to the ROOT forum and thank you for the feedback!

I’m currently maintaining our Docker releases (a little part of my time).

I agree for “human” use of the containers, less so for usage in continuous integration systems etc. (I’m worried an unminimized image would be much heavier). Before we add one more image, how large is the unminimized image in comparison to the one we currently distribute?


Hi @eguiraud,

the image grows by some % (or few 10 MB) after unminimize, so its harmless IMHO.

Cheers, Stefan

Hi Stefan,
I agree, the difference is small enough (80MB for the uncompressed image, likely less for the compressed version). I added the unminimize to the Dockerfile (, it will be picked up next time we generate an image (i.e. for the next patch release).


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