Main issue I have with #docker since YEARS : permissions denied with images that don't allow custom uid/gid. Since docker is not a virtual machine, if you don't have matching uid/gid on ALL your hosts then you're cooked.

Often long to figure out (find how to activate verbose logging, unclear root cause, ...)
Then thinking about inheriting FROM the image to add your local user.
Realizing you have to build a whole set of images that depend on it...
And finally giving up after hours...

#devops