The centos repo sync scripts can be used to aid in setting up your own local repo.

The main goal of these scripts are to help in creating branches from trunk. This is where
you can freeze a set of tested/vetted patches that you want distributed to users. It also
allows for configuration of patch/update lists for specific environments. For example you
can have different branches for db servers, app servers, web servers, etc. As well as
testing, dev, staging, and prod copies of the trunk branch. All of these branches do
not consume extra disk space because they are using hard links back to the original trunk
source.

./snap-repo.sh
- Use this script to make testing/staging/production branches of the trunk repo.
- Script uses hard links to reduce the disk usage to have multiple branches of a repo.

./update-centos-6.0-trunk.sh
- Downloads the latest os and updates via rsync from a public centos mirror. These are
  synced to trunk. You can reference trunk as the source directly in your yum repo client config
  or setup testing branches to test updates before pushing them to your users.