DRBL (Diskless Remote Boot in Linux) is free software, open source solution to managing the deployment of the GNU/Linux operating system across many clients. Imagine the time required to install GNU/Linux on 40, 30, or even 10 client machines individually! DRBL allows for the configuration all of your client computers by installing just one server (remember, not just any virtual private server) machine

via DRBL – About.

DRBL uses PXE/etherboot, NFS, and NIS to provide services to client machines so that it is not necessary to install GNU/Linux on the client hard drives individually. Once the server is ready to be a DRBL server, the client machines can boot via PXE/etherboot (diskless). “DRBL” does NOT touch the client hard drives, therefore, other operating systems (e.g. MS Windows) installed on the client machines will be unaffected. This could be useful in, for example, during a phased deployment of GNU/Linux where users still want to have the option of booting to Windows and running some applications only available on MS windows. DRBL allows great flexibility in the deployment of GNU/Linux.