classh is yet another wrapper around ssh for running commands on a number of hosts concurrently. It is similar to xCAT, pssh, Cluster ssh, and a gaggle of other utilities. The only pre-requisite for classh is Python 2.4 or later, and no formal installation is required; a copy of the classh.py file is sufficient to run commands. The SSHJobMan class from classh can be used to create custom job management scripts. This class lets you either wait until all output has returned from a batch job or process the results as they become available by incrementally polling the running job. The output, error messages, exit code, and start and completion times of each job are stored in the results. It's been tested on jobs of over 25,000 hosts and handles over 10,000 hosts per hour across a WAN and without noticeable impact on the administrator's host.
SALI (Sara Automatic Linux Installer) is a tool that allows you to install Linux on multiple machines at once. It support several protocols for downloading by way of aria2 to install a machine. For example, BitTorrent and rsync are supported. SALI originates from SystemImager and still uses the same philosophy. It is a scalable method for performing unattended installation. SALI is mostly used in cluster setups.
pexconfig allows you to use a PXE-enabled network card as the first boot device for a system. This software suite also includes PXE-menu tools, which are used to control the booting of networked computers directly from the computer's console at the BIOS level before any operating system has been loaded. The menus provided by these tools can be used for diagnostic purposes, for firmware upgrades, or for selecting an operating system installation method.