I have setup a small Eucalyptus based cloud for my company. I would like to use Nagios to track the load on the Node Controller systems to keep track of how many VMs are deployed on each controller. How can I obtain this information from either the Cluster Controller, or the Node Controllers themselves? The euca2ools only give aggregate information about the cluster itself, but not about the individual nodes.
Disclaimer: I have never used Eucalyptus
However, it looks like Eucalyptus has some sort of built-in ability to send passive check results to nagios, directly:
They apparently provide a README about this, as well: https://geni-orca.renci.org/trac/browser/eucalyptus/eucalyptus-2.0.0/tags/neuca-0.11/extras/README.monitoring?rev=2721
This readme assumes nagios is installed locally, but you could cram NSCA in the middle, to forward results to another nagios instance.
Here is a write-up that someone else put together (see step 4): http://www.soa.si/2011/07/25/monitoring-eucalyptus-cloud-with-nagios-and-ganglia/
Installing nagios client on each virtual instance, and setting a nagios server on e.g. CC machine is not an option?