Zenoss is a powerful, easy-to-use, open source IT systems monitoring and management product.
The goal of Zenoss is to provide an affordable, more usable, and open alternative to the big "enterprise management" suites.
Zenoss today provides a complete set of systems monitoring functions including: configuration discovery, availability monitoring, performance monitoring, event management and alerting.
Over time, Zenoss will expand to offer additional "management" functionality through further development and selective partnering with other open source projects.