Once you have installed PDSH you may want to take advantage of group host files. This allows you to dictate a file, known as a group file, with a list of hosts inside of it. You can then pass the name of the group file to your PDSH command to execute your commands against all of the hosts in the group file.
In order to do so you need to install and enable the Group Host files module in PDSH. You can download PDSH and the pdsh-mod-dshgroup module file from http://sourceforge.net/projects/pdsh/
rpm -i pdsh-mod-dshgroup
Verify it is installed (you should see the version number spit back)
rpm -qa pdsh-mod-dshgroup