1.13 Removing the RHCK from a System

If you need to remove the RHCK from a system, you can use the kernel-transition package to prepare the system for removing the RHCK without removing dependent packages such as bluez, fuse, and irqbalance that might be needed for system operation. The kernel-transition package does not contain any files itself but instead it transfers the package dependencies from the kernel package to the kernel-uek package.

Note

You must have subscribed the system to be transitioned to the ol6_latest channel on ULN.

Because the xorg-x11-drv-nouveau package requires kernel-drm-nouveau version 16 but kernel-uek provides kernel-uek-drm-nouveau version 12, removing the RHCK also removes xorg-x11-drv-nouveau. If you use this procedure on systems with Nvidia graphics hardware, the graphical interface will become low resolution and slow.

To transition a system from the RHCK to the UEK:

  1. Install the kernel-transition package on the system:

    # yum install kernel-transition

    This command changes the dependencies for important packages from the RHCK to the UEK.

  2. Remove the RHCK:

    # yum remove kernel

    This command prompts you before removing remaining packages that depend on the RHCK.

    Caution

    When yum prompts you to remove a package, only remove packages that relate to the kernel package. If you are prompted to remove a package that your system requires, enter n to prevent the package being removed. You should also retain any other dependent packages.

    Running the yum update command subsequently will update only the UEK.

If you want to reinstall the RHCK, use the following command:

# yum install kernel

You can also use kernel-transition with kickstart installation. Include the following lines in the %packages section to install the kernel-uek and kernel-transition packages but not the kernel package:

-kernel
kernel-transition

If you create a customized installation ISO, you can replace the kernel package with kernel-transition so that dependency resolution will pull in kernel-transition instead of kernel. If kernel-transition is present on the installation media, it cannot be installed accidentally because it provides a kernel version that is lower than that of any RHCK.