I want to customize CentOS 6 minimal iso by adding some packages or replacing existing ones. For example, I'd like to to replace the kernel package with kernel-xen rpm. I replace it directly, createrepo repodata.xml files and finally make a new iso. When I use the new iso to install at my computer, it notifies me that no kernel package will be installed and bootloader will be the default.
I guess there must be one file which controls which packages are installed but I can't find it in the original iso. Maybe it's in install.img? I searched the Internet but couldn't find any useful information. Can anyone give some clues or suggestions or tell me how to make the iso from scratch or any useful document links?