Really? I've been doing an entirely network based install, and it doesn't work pointing at updates. Could you post a specific setup that works?
My package selection is the absolute minimum with a few useful tools and a few required things I know I don't need like firmware yanked. I use a bit of grep etc on `yum groupinfo base` to figure out what the min requirements are.
abbreviated:
install url --url= http://ftp.telus.net/pub/centos/6/os/x86_64/ --proxy=http://foo:xx repo --name=Updates --baseurl=http://ftp.telus.net/pub/centos/6/updates/x86_64/ --proxy=http://foo:xx ...
#%pre #sleep 999999999
%packages --nobase # Package Preparation, there is no dns, yum or perl in %pre, deduce minimum package # selection ahead of time. ...
%post ...