Nagios Varnish performance plugin

Varnish is a web application accelerator and sits in front of your web server. It speeds up your application by caching some, if not all of the content meaning it reduces the load on your web server and can reduce the load on you backend as less lookups will be needed by the frontend. As varnish is the first thing users hit it is imperative it is working properly and you have statistics on how it is performing.