GNU parallel is a shell tool for executing jobs in parallel locally or using remote computers. A job is typically a single command or a small script that has to be run for each of the lines in the input. The typical input is a list of files, a list of hosts, a list of users, a list of URLs, or a list of tables. If you use xargs today you will find GNU parallel very easy to use, as GNU parallel is written to have the same options as xargs. If you write loops in shell, you will find GNU parallel may be able to replace most of the loops and make them run faster by running several jobs in parallel. GNU parallel makes sure output from the commands is the same output as you would get had you run the commands sequentially. This makes it possible to use output from GNU parallel as input for other programs.
Dpsyco is a automated system to distribute system configurations to several computers. It is written mainly for the Debian distribution but should be portable (without too much difficulties) to other distributions or Unixes as well. It consists of a number of shell scripts to perform the desired actions. With it you can handle users, add ssh-public-keys, patch the system, update things using cfengine, install files (overriding other package files), and more.
C3 Power Tools are a set of Python scripts that ease the use and maintenance of single and multiple clusters. Of the seven core tools, only two are restricted to root use. The C3 tools stand out from similar cluster tools in that they transparently support multiple clusters as easily as a single cluster. These tools are so flexible that they can also be used on groups of workstations not configured as a cluster.
openMosixLOAF (openMosix Linux-On-A-Floppy) is a single floppy openMosix Linux mini-distro designed for harddiskless systems or HPC clusters where only CPU and memory is needed. It has drivers for all PCI Ethernet NICs that the Linux kernel has support for (10/100/1000) and comes on only one bootable 1.6MB 3½" floppy diskette, ready to be a node in your HPC cluster.
p-run is a utility that runs a program, script, or series of commands on a large number of hosts in parallel. It simplifies management of machines in computer labs. It uses ssh, and supports password and key-based authentication. p-run uses libexpect, and will run in parallel across as many processes as specified. When run on a large number of hosts, its parallel nature significantly speeds up administration.