yumbootstrap is a tool for installing Yum-based distributions (Red Hat, CentOS, Fedora) in a chroot directory. Idea behind it is stolen from Debian's debootstrap. It's planned for yumbootstrap to work along with templates for lxc-create.
There is another project of similar purpose called Rinse. yumbootstrap differs from Rinse as follows:
yumbootstrap uses Yum to resolve dependencies, so adding packages to installation list is easier (no need to track dependencies manually).
Using multiple Yum repositories for installation is supported.
yumbootstrap checks signatures on installed RPM packages.
yumbootstrap doesn't depend on Yum mirror to list directory contents, so it's less work to setup local mirror usable with yumbootstrap.