High availability clustering technology has long been the domain of expensive, proprietary systems.

Sun Microsystems may well be changing that; the systems vendor will open source its Open HA (High Availability) Cluster code to Sun's OpenSolaris community in stages over the next 18 months.

"The intention is to foster an open community, including the ability for non-Sun people to put code back to the open source gate," Keith White, director of Solaris software engineering, told internetnews.com. "Initially, we will closely mimic the OpenSolaris process."

Earlier this year OpenSolaris, Sun's community Solaris development effort, began to open up the project to allow for even more participation from its community of users and developers in terms of both governance and technology contributions.

According to Sun's definition of the technology, High-Availability (HA) Clusters are a class of tightly-coupled distributed systems that provide high availability of services through hardware and software monitoring and hardware redundancy.

Sun is not open sourcing all of the technology in one swoop but is spreading out the contribution over an 18-month period that will comprise three distinct stages. The first phase includes the application agent modules that enable applications to plug into the high availability environment.

Sun will also open source the Solaris Cluster Automated Test Environment (SCATE) test framework and suite in the first phase of the process. Testing agents for Solaris Containers, the BEA Weblogic and PostgreSQL will accompany SCATE. Other agents are in the works.

"The Oracle agent code is still being worked through to make sure there are no encumbrances," White said. "Once that is done we will open the source for that agent as well."

Don't expect to be able to jump in right away with the phase one code release and visually see what's going on, at least with open source code.

"The GUI/UI will be part of the open source in phase two and three," White admitted. "The phase two will include the geographic edition [our disaster recovery solution] and phase three is the whole infrastructure and UI."

By the end of the third phase, White expects that there will be a completely open source version to run on OpenSolaris. In the meantime, Sun is providing binaries for the portions that they have not yet open sourced.

Though OpenSolaris is Sun's first official target, Sun is hoping that others in the open source community will benefit as well.

"We are looking to attract members of the community from wherever there is interest," White said. "Given this is the first commercially successful open cluster product, there is likely to be interest from those communities."