How do I downgrade the software image back to a previous distribution version?

How do I downgrade the software image back to a previous distribution version?

Example: Reinstalling an initial base image

Sometimes the administrator may want to downgrade the software image to a previous version of the base distribution. This might be, for example, because of a hardware driver incompatibility.

To do this:

1. Verify that there is an archive of the base distribution release that was used for the initial installations. This is inside the path /cm/local/apps/cluster-tools/basetar/. For example, CENTOS6.tar.gz
2. The cm-create-imagetool can then be used to create a software image with, for example, CentOS 6.3 as the base OS release:

   # cm-create-image -a /cm/local/apps/cluster-tools/basetar/CENTOS6.tar.gz -n centos63-image

3. Set the software image for the category to which the regular nodes need to be downgraded. This can be achieved by using:
   category use default; set softwareimage centos63-image
   in cmsh, assuming that the target category is default.

Possible issues with YUM configuration during cm-create-image step:

1. Subscription required

If the base distribution is free (not RHEL or SLES), and the cluster has internet access, then just proceed ahead with the cm-create-image step as the YUM repositories are already configured correctly for these by default.

However, distributions like RHEL and SLES, require a subscription to access their YUM repositories.

The cm-create-image tool displays the following confirmation message about the base distribution release repositories, to check if they are accessible.

******************** IMPORTANT ****************************
Please confirm that the base distribution repositories for the software image are enabled. For instructions on how to enable repositories for your software image, please refer the administrator's manual.

Image creation can be resumed in one of the following ways:
-----------------------------------------------------------
1. Enter 'e' to exit, and configure repositories. Then, restart program with the -d (--fromdir) option. cm-create-image -d /cm/images/centos63 -n centos63
2. Open a new console, and configure repositories. Then enter 'c' on this console, to continue software image creation.
***********************************************************

Continue(c)/Exit(e)? 

Check the Bright Administrator Manual for details on how to handle this.

2. libsensors transaction check error

 (rt3961)

The following known issue might occur during the image creation process:

[...]
Transaction Check Error:
file /usr/lib64/libsensors.so.4 from install of lm_sensors-3.3.2-69_cm6.0.x86_64 conflicts with file from package lm_sensors-libs-3.1.1-17.el6.x86_64
[...]

 It can be dealt with by using the following command, and then re-running cm-create-image

chroot /cm/images/centos6.3 rpm remove lm_sensors-libs --nodeps