In the latest round of open-sourcing all of its software, Sun is going to be releasing its clustering code to developers over the coming weeks. I'd think that Sun knows a thing or two about clusters, so even if the open source community doesn't build clusters using Solaris, there's likely a few ideas in there that could be picked up along the way.

"Among the agents are modules for Sun's Solaris Containers virtualization technology, BEA Systems Inc.'s WebLogic application server and the open-source PostgreSQL database."