Store /etc under Version Controlhttp://joeyh.name/code/etckeeper/
The etckeeper program is a tool to let /etc be stored in a git,
mercurial, bzr or darcs repository. It hooks into yum to automatically
commit changes made to /etc during package upgrades. It tracks file
metadata that version control systems do not normally support, but that
is important for /etc, such as the permissions of /etc/shadow. It's
quite modular and configurable, while also being simple to use if you
understand the basics of working with version control.