Cacti

Cacti is a complete frontend to RRDTool. It stores all of the necessary information to create graphs and populate them with data in a MySQL database.

Homepage: http://www.cacti.net/

Component monitoring (services and what-have-you)

• Apache
• Nginx
• MySQL - see http://forums.cacti.net/about11010.html
• BIND9 - see http://forums.cacti.net/about3018.html
• memcached
• lmSensors - see http://forums.cacti.net/about11590.html

Related

• Server Monitoring with Cacti + ServerStats
• Useful Cacti Templates to Monitor Your Servers
• Debug NaN's in your graphs
• Nagios
• snmp
• A nice concise example of a MySQL query written in PHP can be found here