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What is the objective of the illumos project?

illumos is a fully open community project to develop a reliable and scalable operating system. It began as a fork of the former OpenSolaris operating system.

Our goal is to foster open development of technologies for the 21st century while building on a twenty-year heritage, but free from the oversight of a single corporate entity and the resulting challenges thereof.

While our code base has a long history and many engineering traditions attached to it, our development processes are being reinvented in an attempt to remove barriers while maintaining consistently high code quality.

How do I download the software?

The source code developed by the project is a fork of the Sun/Oracle code base referred to as "OS/Net" or "ON" (short for Operating System/Networking). It is the home of the technologies that previously defined OpenSolaris and Solaris, such as the kernel, network stack, filesystems, and device drivers, and all of the basic userland libraries and applications.

The illumos code base forms the foundation of distributions including a storage appliance from Nexenta, a cloud platform from Joyent, and the general-purpose OpenIndiana.

To use the operating system, just download and install one of the distributions. OpenIndiana is a general-purpose system suitable for users and developers. OmniOS is aimed squarely at server use. Joyent has SmartOS for hosting applications and virtual machines.

To download the source code, follow the section on Git or Mercurial in How To Build illumos. You can also browse and search the illumos code online.

Is illumos free software (open source)?

The bulk of the illumos source code is available under the Common Development and Distribution License (CDDL), an OSI-approved free software license based on the Mozilla Public License (MPL).

There are some components with other licenses including BSD and MIT. We also include some software with the GNU General Public License (GPL) or the Lesser/Library General Public License (LGPL).

There still remain some binary-only, closed source components that we inherited from Oracle which we are working to replace. Unlike OpenSolaris, we do not require a closed source compiler.

Is illumos a Nexenta or Joyent project?

illumos was initiated by then-employees of Nexenta in collaboration with former OpenSolaris community members and volunteers. While companies including Nexenta, Joyent, and Delphix sponsor some of the work in illumos, the project is independent of their business decisions. illumos exists as a common base for multiple commercial and community distributions.

Is illumos a community project?


It is run by the community on a system of meritocracy. Multiple community groups and interests (including people like you!) are stakeholders in the project, and anyone and everyone is welcome to contribute.

How do I start contributing?

illumos thrives on the efforts of its contributors. Have a look at the guide on How To Contribute if you want to submit code. If you want to help in other ways then have a look at the Mailing Lists and other ways to contact us to see if there are any other places where help is needed.

Most of the developers can be found on IRC and you're invited to drop in and say "hi!"

How do I build illumos?

See How To Build illumos.

How do I build a distribution based on illumos?

OpenSolaris was historically difficult to build as a distribution because it was assembled by many separate teams at Sun. The illumos community distributions are working to make this easier.

Some distributions have documented their build processes: OpenIndiana, OmniOS.

Is illumos compatible with Solaris/OpenSolaris?

Yes! We highly value binary compatibility for applications and drivers. If your application runs on Solaris but not on illumos, then tell us, because it's a bug!

Note that we can only claim Solaris compatibility for versions of Solaris released before the fork. Solaris 10 update 11, and Solaris 11, may contain incompatible changes.

What changes does illumos maintain?

illumos maintains:

  • Open internationalization libraries and data files.
  • Open replacements for closed binaries.
  • Code that Oracle may choose to no longer maintain.
  • Community enhancements to critical technologies like DTrace and ZFS.
  • New open technologies.
  • Patches/bug-fixes we have independently developed, including security fixes.
  • Changes to ease community development.
  • ...and more!

Will you track Oracle changes?

We originally intended to closely follow upstream changes, but became a fork by necessity because Oracle's software is no longer open source. We now represent the open future of the code base after Sun.

It is uncertain if Oracle will ever open source their version of ON again. If this happens in the future, their changes will be evaluated on a case-by-case basis for integration.

Will you work on sending illumos changes upstream?

We would like Oracle to use changes from illumos, as long as they are willing to abide by the open source license for our code. Where we use code from other free software projects, we also respect their licenses and keep the source open.

Why did you announce the project after it was set up and much of the code written?

This decision was made for multiple reasons. The signal to noise ratio in the OpenSolaris community had grown low, and announcing the project would have distracted the developers from actual code and contribution. Most vocal members talked about opening the code rather than writing it. illumos chose the opposite. Before the formal announcement, we reached out to developers in the community and solicited their help and participation.

Some choices of project infrastructure were not made by a community vote - what drove these choices?

These initial infrastructure choices, of using hosting graciously provided by Stanford University, and Redmine as the project management software to power the projects and bug tracking were made by individuals in the project to get the work done as quickly as possible. Redmine is easy to use, provides all required functionality in a single package, and we felt it was a good choice for all planned illumos development.

We have since migrated to hosting facilities offered by Joyent, and are migrating part of the content infrastructure from Redmine to this wiki and other tools.

And the name illumos?

We started off with the codename "FreeON", and later realized it is used by an existing project. We finally settled on illumos, after many hours of suggestions and counter-suggestions. illumos (pronounced i-llu-MOS and written in lowercase) ties in with Sun and light. It's the closest to ON we could get!