Monitoring Apache with SNMP

There are a couple of open-source modules that add Simple Network Management Protocol (SNMP) capabilities to the Apache web server. This protocol is commonly used to manage network servers and equipment from a central console such as HP OpenView and Tivoli. With this module, you can easily monitor Apache performance in real time, including server uptime, load average, number of errors in a certain period of time, number of bytes and requests served, and many other metrics. The SNMP modules can also generate alarms when a certain threshold or error condition is met, such as a sudden increase in the number of simultaneous client connections.

For Apache 1.3, you can use mod_snmp, which can be found at http://www.mod-snmp.com/ and supports SNMP version 1 and 2. It requires patching of the Apache core.

For Apache 2, you can use a similar module called mod_apache_snmp. It can be found at http://modapachesnmp.sourceforge.net/. This module supports versions 1, 2, and 3 of the SNMP protocol and can be compiled as a DSO, without the need to patch Apache.

A number of open-source tools and frameworks allow you to manage SNMP resources, such as the tools at http://www.net-snmp.org, OpenNMS (http://www.opennms.org), and Nagios (http://www.nagios.org).