- First you need X11. If you have an older version of Mac OS X then X11 should already be installed.
- If you are running Mountain Lion (OS X 10.8) or newer, then you can download X11 here: http://xquartz.macosforge.org/landing/
sudo yum -y install firefox Xvfb Xorgyum -y groupinstall "X Window System" "Desktop" "Fonts" "General Purpose Desktop"cf http://alexbischof.blogspot.com/2012/11/centos-installing-graphical-x-window.html
How is that headless? You install the whole graphical environment!