You can take one or more virgin PCs, turn on the power and after a few minutes Linux is installed, configured and running on all your machines, without any interaction necessary.
FAI it's a scalable method for installing and updating all your computers unattended with little effort involved. It's a centralized management system for your Linux deployment.
FAI's target group are system administrators who have to install Linux onto one or even hundreds of computers. It's not only a tool for doing a Cluster installation but a general purpose installation tool. It can be used for installing a Beowulf cluster, a rendering farm, a web server farm, or a linux laboratory or a classroom. Even installing a HPC cluster or a GRID and fabric management can be realized by FAI. Large-scale linux networks with different hardware and different installation requirements are easy to establish using FAI and its class concept. Remote OS installations, Linux rollout, mass unattended installation and automated server provisioning are other topics for FAI.
Read More at : http://www.informatik.uni-koeln.de/fai/