one server or more ?
first of all in RH the system will not reboot after update
some service my get restart (ssh,mysql,http) but never reboot and as side note you can block the kernel from upgrade
if its more then one server the look as using samting more "easy" like spacewalk
it can manage all the servers and upgrade one rpm or all very easy and can send you daily report of RPM need to be upgrade
one last way is to add the centos errora email list and look every day for updates