=======================
Upgrading Linux kernel
=======================

From time to time, Debian issues kernel updates to fix bugs or security
issues. Basic kernel upgrades (for example, from 3.2.63-2+deb7u1 to
3.2.63-2+deb7u2) occur with a normal ``apt-get update`` command, but
upgrades from between major kernel versions require special commands.

It is not recommended to upgrade a node kernel to a new major version
unless it offers a new feature you need or fixes a specific bug
affecting your environment.

Upgrading the kernel
---------------------

To simplify the upgrade process, we provide a package
``bonding-kernel``, which will install the latest Linux kernel we
support. Installing the latest kernel is simple

::

    root@hostname:~# apt-get install bonding-kernel

A reboot is required to use the new kernel.

::

    root@hostname:~# reboot

After the reboot, the node will be using the latest kernel, and can be
verified with the uname program

::

    root@hostname:~# uname -r
    4.19.44

Finding firmware packages
--------------------------

Debian kernel packages can add or remove hardware support compared to
previous versions. The upgrade process will warn you if required
firmware is missing, with messages such as:

::

    W: Possible missing firmware /lib/firmware/tigon/tg3_tso5.bin for module tg3
    W: Possible missing firmware /lib/firmware/tigon/tg3_tso.bin for module tg3
    W: Possible missing firmware /lib/firmware/tigon/tg3.bin for module tg3

If all the hardware is working correcltly, it is safe to ignore this
message as the firmware is likely in the kernel itself. If some of the
hardware is not working correctly, you can find and install the extra
firmware packages necessary.

This indicates that the new kernel may be missing firmware files
required for the hosts's TG3 network hardware. If you see this message,
search `Debian package
repositories <https://www.debian.org/distrib/packages#search_contents>`__
to find which package includes the firmware. For example, given the
above message, you might search package contents for "tg3.bin".

|image0|

The search results for tg3.bin show that the file is included in the
``firmware-linux-nonfree`` package.

|image1|

To install the ``firmware-linux-nonfree`` package, run:

::

    apt-get install firmware-linux-nonfree

If the Debian search doesn't return any packages, you might try searching
Google for the entire warning message. Relevant search results could tell
which package includes the necessary firmware. If you are unable to find
a suitable firmware package, please contact technical support.

.. note::

    firmware-linux-nonfree and firmware-linux-free are installed by default
    with the bonding-kernel package

Further reading
----------------

`Debian documentation: How to upgrade
kernel <https://wiki.debian.org/HowToUpgradeKernel>`__

.. |image0| image:: /attachments/10158110/10354689.png
.. |image1| image:: /attachments/10158110/10354690.png
