Cobbler is a Linux installation server that allows for rapid setup of network installation environments.
With a simple series of commands, network installs can be configured for PXE, reinstallations, media-based net-installs, and virtualized installs (supporting Xen, qemu, KVM, and VMware Server). Cobbler uses a helper program called 'koan' (which interacts with Cobbler) for reinstallation and virtualization support.
Cobbler can also optionally help with managing DHCP, DNS, power, config management, and yum package mirroring infrastructure -- in this regard, it is a more generalized "batteries included" deployment server, rather than just dealing specifically with installations. It has a command line interface, a web interface, and also several API access options.