CentOS 6 Minimal or Hardened Install

Solution 1:

The US National Security Agency (NSA) provides guides for hardening Linux and other operating systems which may be of some help. Since CentOS is so similar to RedHat, you may be intrested in:

• Guide to the Secure Configuration of Red Hat Enterprise Linux 5
  
• Hardening Tips for the Red Hat Enterprise Linux 5

Solution 2:

The lightest install you can do will require Kickstart with the below option:

%packages --nobase

You will need to experiment to figure out what packages you will explicitly want to include after that. At minimum you'll probably want to include these just to get started.

%packages --nobase
openssh
openssh-server
yum

Regarding a secure/hardended install, DISA provides STIGs for Linux. It's hard to navigate, but it's out there... I hate linking, but it's too much to copy/paste here. Check this for a Kickstart with DISA STIGs. https://nazar.karan.org/cgit/bluecain/tree/ (secure-kickstart.cfg)