xCAT software and repo files can be obtained from: http://xcat.org/download.html
[xcat-core]
For the xCAT version you want to install, download the xcat-core.repo file and copy it to /etc/yum.repos.d
[xcat-dep]
From the xCAT-dep Online Repository, navigate to the correct subdirectory for the target machine and download the xcat-dep.repo file and copy it to /etc/yum.repos.d.
Continue to the next section to install xCAT.