Let's assume you have your systems farm. From one of them you are able to connect to all others with ssh keys already configured.
Now, you create a list with all these systems in it. If you want to temporary skip one system, just put # in front of it, like in our example (server2 disabled).
The ssh options are there to assure you that even if you have ssh configuration problems or one server is down, you won't get stuck on that and everything will go smooth to the end.