External monitoring is one of the key tasks of the operations department. System engineers have to be able to measure performance degradation in the live setup in order to inform the developers, who in turn have to seek for solutions for these problems. Without monitoring no measurement is possible. Without measurement no debugging will happen. Icinga provides a pretty simple kind of monitoring. You can check whether your service, which is in our case the Play application, responds to a simple request or has to be marked as down.
One of the tools used for such tasks is Icinga, which is used for monitoring of whole networks and service landscapes. Icinga is a fork of the common Nagios monitoring system. It has been forked due to problems in the open source development process.
The source code is available at examples/chapter7/ssl/example-app
for the example application used and in examples/chapter7/icinga
for the Icinga specific files.