This a software to run commands on a set of servers.
For example 'pdsh -a uname -av' will give you "uname -av" of all machines.
http://techsnail.com/howtos-tutorials/installing-pdsh-on-hpc-cluster/
It can be installed from rpmforge.0
wget http://packages.sw.be/rpmforge-release/rpmforge-release-0.5.2-2.el6.rf.x86_64.rpm rpm -ivh rpm-release* yum install pdsh
after that you can immediately run "pdsh -w oss1,client1 uname -av" to run a command on a remote node.
It's possible to set up so that it executes on a pre-defined list. Check out /etc/machines.
Extremely useful if you want to save some time :)