39.2. Preparing to Upgrade

39.2. Preparing to Upgrade

Before upgrading the kernel, it is recommended that you take some precautionary steps. The first step is to make sure working boot media exists for the system in case a problem occurs. If the boot loader is not configured properly to boot the new kernel, the system cannot be booted into Red Hat Enterprise Linux without working boot media.

To create a boot diskette, login as root, and run the command /sbin/mkbootdisk `uname -r` at a shell prompt.


Refer to the mkbootdisk man page for more options. You can create bootable media via CD-Rs, CD-RWs, and USB flash drives, provided that your system BIOS also supports it.

Reboot the machine with the boot media and verify that it works before continuing.

To determine which kernel packages are installed, execute the command rpm -qa | grep kernel at a shell prompt:

The output contains some or all of the following packages, depending on the system's architecture (the version numbers and packages may differ):


From the output, determine which packages need to be download for the kernel upgrade. For a single processor system, the only required package is the kernel package. Refer to Section 39.1, “Overview of Kernel Packages” for descriptions of the different packages.

In the file name, each kernel package contains the architecture for which the package was built. The format is kernel-<variant>-<version>.<arch>.rpm, where <variant> is one of either PAE, xen, and so forth. The <arch> is one of the following: