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Janus Lives Through BrandZ

Among the potential obstacles that face migrants to Sun Solaris is their ability to run Linux applications.

Sun has long been working on ways to overcome that issue and has now launched a re-branded OpenSolaris effort called BrandZ to open the door for Linux applications to run on Solaris.

Originally, the promise of running Linux applications on Solaris was developed under the code-name Janus. Sun introduced it in April 2004 and previewed it at LinuxWorld in August that year. The technology has yet to be incorporated into the mainline Solaris 10 release.

BrandZ is the underlying framework that allows Solaris to create Linux zones, as well as other non-native zones on a machine running Solaris.

The initial lx zone that Sun is developing in BrandZ will allow Red Hat Enterprise Linux, as well as CentOS-based applications, to run on Solaris.

CentOS is a clone of Red Hat Enterprise Linux (RHEL) and, as opposed to RHEL, is available for free without the need for users to purchase subscriptions.

According to Paul Steeves group manager of Solaris product management at Sun, the company is looking to expand its relationship with CentOS.

"We are looking at ways we can support the CentOS effort, given that we do make significant use of their distro," Steeves told internetnews.com. "Talks so far have been going well, and the CentOS guys are very excited about the work we are doing."

BrandZ is not, however, limited to Red Hat and its clones, or even just Linux. Steeves noted that it may someday be possible to have a Red Hat zone, a Debian zone, and a SUSE zone all running on the same Solaris 10 system.

"BrandZ could also be used to develop brands that support a FreeBSD zone, a Darwin x86 zone, or variant Solaris zones that contain non-standard software collections," Steeves said.

Sun recently announced that Solaris will also support open source Xen virtualization technology.

Xen and BrandZ are complementary and not competitive technologies, according to Steeves.

"Xen virtualizes the hardware, which allows multiple operating-system kernels to run simultaneously on [currently] one piece of physical hardware," Steeves explained. "Solaris Zones virtualize the OS, allowing multiple operating system environments to coexist on a single Solaris kernel."

"Thus the two technologies can either be used independently or used in combination to provide whatever set of attributes best fits the problem at hand."

The BrandZ roadmap is still being refined, and Steeves noted that Sun expects to update the community at a later date.

"The community take-up and reaction to BrandZ will also have an impact on things like test cycles and the necessity to run a beta program," Steeves said. "We should know more in January.

Steeves said the BrandZ Web site provides the community with a non-comprehensive list of the functionality Sun intends to add to BrandZ before integrating it into Solaris.

"The list includes features to enhance the functionality of BrandZ, as well as bugs to be fixed. Requested features include system calls, networking functionality and other additions, such as support for sound in a Linux zone."

So how did Solaris come to support Linux apps? Get your scorecards ready, because the road actually involves three different names.

Steeves explained that Janus was released as a technology preview under the name "Linux Application Environment" to a small number of customers earlier this year.

"BrandZ represents the follow-on project to Janus, incorporating architectural improvements and tighter integration with the Solaris Containers feature," Steeves said.

So did Janus become Linux Application Environment and then BrandZ, which is the same as Solaris Containers? Not quite.

"Branded Zones, or BrandZ, is the engineering project, or project name, for Solaris Containers for Linux Applications," Steeves explained. "This differs from regular Solaris Containers and has not yet been added to Solaris 10."

Currently BrandZ is only available in the form of a development preview via OpenSolaris, which was recently opened up to the wider OpenSolaris community.

At some point in the future, BrandZ will be included as a Solaris 10 update as "Solaris Containers for Linux Applications."