Vac-in-a-Box (ViaB) aims to make it ridiculously easy to install and configure Vac on your computers. Vac allows you to run VMs from HEP experiments to run their jobs, and ViaB allows you to manage the Vac VM factory machines and the VM settings here on the ViaB website. This way you don't need to use Puppet or configure things manually (Vac's Admin Guide explains how to go down that route if you prefer.)
The factory machines managed by ViaB are autonomous and equivalent, and each one runs all the services needed for installation and operation at your site: DHCP, TFTP, Squid, and Vac. You install the first factory using a USB boot image you can download from this website, and subsequent factories can be installed from the first (and second, and third ...) factory using PXE.
Even though the factories are self-contained, they co-operate to supply each other with DHCP and TFTP services at boot time, and participate in a distributed HTTP cache via Squid peering. This cache is used during installations and by cvmfs. Once Vac is running on a factory it also queries the other factories via the VacQuery UDP protocol to decide what types of VM to start.