According to https://fedoraproject.org/wiki/Anaconda/Kickstart#url it should be possible to use $releasever and $arch in the 'url' kickstart parameter and have them substituted appropriately, but this does not appear to work. I've tested with 19, 20 and 21/rawhide, it does not work in any of them; I'm filing this against 20 because I believe the situation for 21/rawhide is complicated by the use of dnf.

There is a kickstart at http://fedorapeople.org/groups/qa/kickstarts/base-net-generic.ks which should be usable to reproduce this bug, it contains the following line:

url --mirrorlist=https://mirrors.fedoraproject.org/mirrorlist?repo=fedora-$releasever&arch=$arch

but when booting a netinst ISO from 19, 20 or 21 with 'inst.ks=ttp://fedorapeople.org/groups/qa/kickstarts/base-net-generic.ks' , the installer stops at the hub with the Installation Source hub in error state, showing the message "Error setting up base repository". If you enter the hub, it shows the URL exactly as written in the kickstart - that is, without $releasever and $arch being substituted.

bcl asked me to look for a line "adding yum repo, name: ..." in the logs, but no such line appears to be present. I will attach logs from a Fedora 20 reproduction of this bug, using the official release F20 x86_64 netinst.iso image.