Master/node to gather and graph "everything" on your systems using Tobi Oetiker's rrdtool. It can optionally warn your surveillance software. This software package was originally called LRRD. The project. Please see http://munin-monitoring.org/
WebInject is a tool for automated testing of web applications and web services. It can be used to test system components with HTTP interfaces, as a test harness to create a suite of functional and regression tests, or for service-level monitoring.
A tool for Multi-Router Traffic Graphing software, MRTG Spike Remover removes anomalous "spike" data from the MRTG logs in order to faciliatate reading the parts of the graph important to the surveyor, leaving out irrelevant data outliers.
SysUnit is a JUnit framework for distributed testing, system testing and integration testing. SysUnit is ideal for testing highly distributed software such as clusters of web applications, web services or MOM based software