Nagios vs Icinga: which should I use?

Solution 1:

I would recommend taking a look at Icinga. It's a very active spark of nagios with regular updates. On top of that, it's 100% compatible with nagios-plugins.

The advantage of Icinga is that the make one API available to talk with, instead of a bunch of them. In Nagios you can get info from the Core, Cache, NDOMod, NDO2DB, the MySQL DB, Command line,...

Icinga also has a beautiful and easy-to-use web interface. You can also use NConf with it, which is awesome. Here is a video explaining the differences: http://www.youtube.com/watch?v=jLqhXvGTazI

(It's from Icinga, so it might be a bit biassed)

Solution 2:

I use nagios exclusively, and I find configuration to be a piece of cake. I simple create a directory for each "type" of device being monitored, and then a new file for each device. By doing it that way, it's REALLY easy to manage. Plus, I love the ease in writing new plugins... And yes, as far as Nagios goes, it is still in active development (As far as I can tell, they are releasing new versions)...