Hi Vagrantin,
If I'm reading this right, the four-slash path is the tell. I can't confirm without seeing your exact Docker invocation, but this pattern points pretty clearly at one thing.
misc.sh builds its temp dir from $PWD; something like $PWD/tmpdir-XXXXXX. If Docker is running your build from /, that expands to //tmpdir-XXXXXX. Linux is fine with that. Yum is not. It turns the config path into a file:// URI, and ////tmpdir-VcYHGW/yum-171swX.conf is not a URI anything wants to parse.
One other thing worth knowing: a :ro read-only mount on your repo directory causes the same symptom. mktemp fails silently, TMPDIR ends up empty, and you get the same mangled path. Different cause, same four-slash result.
Two things to try. The faster diagnostic is just cd into your repo before calling the script: if the build completes, that was it. The cleaner fix for scripted runs is passing -w /path/to/your/repo to your docker run command, which sets the working directory explicitly.
Before you do either, this will tell you what you're actually dealing with:
echo $PWD && ls -la $TMPDIR
That's my best guess, at least. I'm curious what those two commands show.
