[CentOS] CentOS, linux and kernel version

Thu Dec 19 17:50:10 UTC 2013
Keith Keller <kkeller at wombat.san-francisco.ca.us>

On 2013-12-19, Jayadevan Maymala <jayadevan.technology at gmail.com> wrote:
> I am using CentOS 6.4.
> uname -r gives me
> 3.9.3-x86_64 Kernel version is 2.6.32. My questions -

Your current running kernel version is 3.9.3.  Someone has installed
a kernel from a source other than the base CentOS repository and booted
it.  You may have 2.6.32 installed somewhere on this box, but it wasn't
used for this boot.

> What is 3.9? In Ubuntu, uname -r and /boot give the same version numbers.

/boot is not authoritative for the running kernel, because /boot can
hold many different kernels (or really anything you put there).  uname
is authoritative for the current running kernel, and grub is (mostly)
authoritative for the kernels available on the next boot.

> Do we have a mapping of CentOS versions, the numbers like 3.9 and
> kernel versions maintained somewhere?

You can look in the vault:


Keep in mind that there may be more than one distributed kernel for a
given CentOS release, since there are updates to packages as well.


kkeller at wombat.san-francisco.ca.us