Kernel versioning

Versioning

Currently all new OpenVZ kernels has a simple version like 2.6.n-ovzXXX

2.6.n is a vanilla kernel version, e.g. 2.6.20 or 2.6.22, which this OpenVZ kernel is based on;
ovzXXX is the OpenVZ kernel version, e.g. ovz001 for the very first one.

Some time ago OpenVZ kernel versions were named like 2.6.n-XXXtestYYY.z and 2.6.n-XXXstabYYY.z.

2.6.n is a vanilla kernel version (i.e. the one from kernel.org) which this OpenVZ kernel is based on.
XXX is a major OpenVZ kernel version number, which usually changes from release to release, or when dramatic changes to the kernel are made.
test series kernels are unstable kernel releases, which are usually under extensive development, while stab series kernels are more or less stable kernel releases which are close to be released or are in production already.
YYY is a minor OpenVZ kernel version number, which changes from build to build, when bugfixes or small feature changes were made.
z is an add-on number; it is used as rpm's Release field and in most cases is set to 1.

This style is kept for some kernels that started before switching to the new versioning.

Usual kernel development cycle looks like this:

021test000 → 021test001 → ... → 021test012 → here kernel is declared stable → 021stab000 → 021stab001 → ... → 021stab023

A few kernel branches may be developed in parallel. For example, as of 13th of June, 2006, there are four branches: