Sun Microsystems has extended certification for the Ubuntu Linux distribution to its Opteron-based servers. 

Canonical, the distribution's commercial sponsor, will bundle Sun's open source GlassFish application server for Java Enterprise Edition 5 that is due out later this year.

Ubuntu started offering the Java Runtime Environment as an optional download in May.

The popular desktop Linux distribution is based on Debian, and is also available in a server version. 

Canonical aims to create a business around the Linux distribution by offering support.

But instead of bundling support with updates through annual subscription plans such as those offered by Red Hat or Novell, Canonical plans to build a network of independent support providers.

Sun started certifying Ubuntu for its Niagara servers earlier this year. The company today is expanding the certification with its SunFire X4100 and X4200 AMD Opteron servers as well as the Sun Ultra 20 and 40 workstations.

Sun is the only mainstream hardware vendor to certify its hardware for Ubuntu.