In this recipe, we'll customize an existing command definition. There are a number of reasons why you might want to do this. A common one is if a check is overzealous, sending notifications for the WARNING or CRITICAL states which aren't actually terribly worrisome; or, on the other hand, if a check is too forgiving and doesn't flag hosts or services as it has problems in recognizing when it would actually be appropriate to do so.
Another reason is to account for peculiarities in your own network. For example, if you run HTTP daemons on a large number of hosts on the alternative port 8080 that you need to check, it would be convenient to have a check_http_altport command available. We can do this by copying and altering the definition for the vanilla check_http command.
