NodeBrain
Rule Engine for State and Event Monitoring
...It interacts with other monitoring components to perform simple element state monitoring or complex event correlation based on user specified rules. It is extended through the development of node modules (plug-ins) using NodeBrain's C API, and servants (programs written in any language) that interact with the rule engine via stdin, stdout, and stderr. The package includes a small set of plug-in modules to provide capabilities typically required for monitoring applications.