I added the EPEL repository to cobbler using the following command-line: cobbler repo add --name=EPEL-5-i386 --mirror=http://download.fedora.redhat.com/pub/epel/5/i386/ --mirror-locally=0 After that I selected the repo under "Yum Repos" in a profile, modified the kickstart template to add some packages ("puppet" among others) and used that profile to install a System (CentOS-5.2). After the installation the puppet package is installed showing that the repo worked properly during the installation but /etc/yum.repos.d/cobbler-config.repo contains this line: # error: could not read repo source: /var/www/cobbler/repo_mirror/EPEL-5-i386/config.repo The directory "/var/www/cobbler/repo_mirror" is empty on the cobbler server (likely because I used the "--mirror-locally=0" option when adding the repo). Cobbler should instead append the repo data used during the installation to the config file.
It appears you still need to run "cobbler reposync" to generate the configuration files this repo will use, even though it is local. If you haven't done this and still have this problem, let me know.
I've confirmed that is in fact how it works, I've opened a RFE in Trac to streamline this for a future release: https://fedorahosted.org/cobbler/ticket/337#preview