The main objective of the talk is to give a detailed real world example how we use Icinga 2 at a large scale with all its pros and cons. SysEleven monitors several hundred heterogeneous projects. To migrate our Icinga 1 setup to a high available Icinga 2 setup we developed icingadiff. The new cluster is fully automated with Puppet, deploys over 60000 checks and enables our engineers to fine tune every check if necessary. To integrate further information and custom workflows we modified Icingaweb2.