Nagios is software for monitoring servers and systems.
Nagios can check many kinds of system metrics:
A Nagios plugin is a system monitoring scripts that print out data in a way that Nagios can understand.
We write our own Nagios plugin scripts to monitor aspects of our system such as how many people are signed in, when critical files are modified, and Ruby On Rails errors.
Phusion Passenger is the software we use to connect our Apache webserver to our Ruby On Rails applications; it is similar to mod_perl.
To use Nagios to monitor Passenger Memory Stats, we created Nagios plugin scripts that work much like the parse shell scripts above.
We monitor these sections:
We monitor these values:
To download our Nagios plugin scripts for Passenger Memory Stats:
You may need to customize these scripts for your own systems, depending on which version of Phusion Passenger you're using, and how your system runs Apache and Passenger.
If you know GitHub and Git, feel free to fork and clone as you like. If you want to improve these scripts, or add to them, feel free to send us a pull request.