monit-pi

Monitoring of a Raspberry PI

These scripts are intended to give you some insights about the usage of your Raspberry. If you also have hooked on it some probes via GPIO e.g., you can follow the evolution of the metrics (for instance your home temperature).

There are two parts to make this happen:

• Python scripts (in the ./monit/ directory) which gathers all the metrics;
• PHP scripts (in the ./www/ directory) to view the different graphics.

All the metrics are defined in the ./monit/def_metrics.py file. All the RRDs databases are defined in the ./monit/def_rrds.py file. If you feel the need to modify the look and shape of the graphics, you should look into the ./www/monit.inc.php.

You will have to adapt the number of CPUs of your platform in ./monit/def_metrics.py (beginning of the file) and ./www/monit.inc.php (end of the file). To deactivate one particular monitoring, you just have to comment the according definitions in ./monit/def_metrics.py (to disable the monitoring) and in ./www/monit.inc.php (to remove the graph). You can obviously add metrics by editing the same files, but don't forget to add the necessary definitions in ./monit/def_rrds.py to specify the characteristics of the RRD database!

If you need help or insights about RRD, a good starting point but also references can be found here: http://oss.oetiker.ch/rrdtool/doc/index.en.html

INSTALL

• Install the RRD API for PHP and Python. On Raspbian, the packages are php5-rrd and python-rrdtool;
• Create a directory (e.g. /var/lib/monit) where you will store the RRD files (the metric historial databases);
• Modify the variable path_rrd in ./monit/def_metrics.py and ./www/monit.inc.php (beginning of the file) to reflect your choice;
• Make this directory Read/Write for the user that will launch the Python script and Read-Only for the user owning the webserver process that will serve the graphics (see below steps);
• Add in your crontab an entry to launch the Python scripts every 5 min. For instance, you can create a file in /etc/cron.d/, with the following content:

*/5 * * * *     pi      /usr/bin/python /home/pi/monit/monit.py

• Make the PHP scripts available from a webserver able to interpret PHP (Apache, nginx, or any other choice). To test, you can also launch $ php -S localhost:10005 in the directory where the scripts reside.
• Make sure the user owning the webserver process have write access to the directory ./www/cache where we will store the PNG files to avoid generating them at each request.

If you want to enable the monitoring of rtorrent as your bittorrent client, just enable the XML-RPC interface via the scgi_local option in your .rtorrent.rc file, and update the ./monit/def_metrics.py file accordingly (see the get_torrent function).

That's all Folks!