I often use a program called shmux to run commands on a number of remote machines via SSH in parallel. There are many different programs (including fanout) tha

I often use a program called shmux to run commands on a number of remote machines via SSH in parallel. There are many different programs (including fanout) that do this, but I think shmux is the best. It can be run in both interactive and non-interactive modes. The interactive mode is curses based and lets you easily control how many of your ssh tasks run in parallel, lets you pause and resume, and nicely separates out the stdout and stderr output. The non-interactive modes let you define what success means in terms out output and return code, and splits out output and return codes into separate files for further processing.