Customizing an existing command

In this recipe, we'll customize an existing command definition. There are a number of reasons why you might want to do this, but a common one is if a check is "overzealous", sending notifications for WARNING or CRITICAL states, which aren't actually terribly worrisome. It can also be useful if a check is too "forgiving" and doesn't detect actual problems with hosts or services.

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.

Getting ready

You should have a Nagios Core 3.0 or newer server running with a few hosts and services configured already. You should also already be familiar with the relationship between services, commands, and plugins.

How to do it...

We can customize...