Comment # 5 on bug 1113811 from Aleksa Sarai

(In reply to Valentin Rothberg from comment #4)
> Notice that it will work out-of-box for new installations and also for new
> users. For existing user, we still need to *manually* add entries to
> `/etc/sub{g,u}id` as described in `man podman`. We also took this occasion
> to improve the error message of Podman in the absence of those files.

I just noticed that the man page actually gives you worrying advice (setting
the mapping range to start at 10k) -- is this man page from upstream? It should
say something more like starting the mapping at 100k or 1m because otherwise
you are going to clash with the 64k range that Linux distributions assume they
own.