sun™ cluster is a platform for making applications highly available. you can get pre-packaged software agents for popular applications (like NFS or
Sybase database), but you can also write your
own agents for applications without a shrink-wrapped solution (such as
Postgresql).
although developing an agent isn't difficult, there are some concepts which you need to understand before you can start, and some techniques you can use to make development easier. we've tried to cover this in
sun cluster 3 programming. feel free to drop questions here.