I wrote down some notes about configuring Nagios to check the health status of a few VMware vSphere ESXi 5.1.0 servers. First of all, install the required packages on the Nagios server:

NagVis (http://www.nagvis.org/) is a visualization addon for Nagios/Icinga that permits to visualize the monitored information as objects placed on maps.  I decided to use mk-livestatus (see: http://mathias-kettner.com) as backend because it is reported to offer better performances than ndo.

Latest Debian major release, Wheezy, ships by default with Ruby Sinatra 1.3.2 and you know what? Foreman will not play well with it! As an example, I couldn’t provision new hosts (a generic error code 400 was thrown, plus lot of ruby complaints on the foreman-proxy log).