On Monday we published code for the Tungsten Monitor, a lightweight pluggable monitor for clusters. The Tungsten Monitor is trivial to set up and can broadcast status notifications using group communications. Users can extend it easily to add new types of monitors or notificiations.
Tungsten FSM is a Java library for finite state machines. It is small, simple to use, and allows users to implement finite state machine designs quickly. The resulting code is both fast and easy to maintain.