We would, as is the point of having monitoring systems, like to get alerted when something actually goes down. We don't want to keep monitoring the Icinga web interface screen, waiting for something to go down. Icinga provides a very generic and flexible way of sending out alerts. We can have any alerting script triggered when something goes wrong, which in turn may run commands for sending e-mails, SMS, Jabber messages, Twitter tweets, or practically anything that can be done from within a script. The default localhost monitoring setup has an e-mail alerting configuration, which we used in the first chapter.
The way these notifications work is that we define contact objects where we give the contact name, e-mail addresses, pager numbers, and other necessary details. These contact names are specified in the host/service templates or the objects themselves. So, when Icinga detects that a host/service has gone down, it will use this contact object to send contact details to the...