Verifying The Initial Ram Disk Image; Verifying The Boot Loader; X86 Systems - Red Hat ENTERPRISE LINUX 5 - DEPLOYMENT Deployment Manual

Chapter 40. Manually Upgrading the Kernel
Important
It is strongly recommended that you keep the old kernel in case there are problems with
the new kernel.
At a shell prompt, change to the directory that contains the kernel RPM packages. Use -i argument
with the rpm command to keep the old kernel. Do not use the -U option, since it overwrites the
currently installed kernel, which creates boot loader problems. For example:
rpm -ivh kernel-<kernel version>.<arch>.rpm
The next step is to verify that the initial RAM disk image has been created. Refer to

"Verifying the Initial RAM Disk Image"

40.5. Verifying the Initial RAM Disk Image
If the system uses the ext3 file system, a SCSI controller, or labels to reference partitions in /etc/
fstab, an initial RAM disk is needed. The initial RAM disk allows a modular kernel to have access to
modules that it might need to boot from before the kernel has access to the device where the modules
normally reside.
On architectures other than IBM eServer iSeries, the initial RAM disk can be created with the
mkinitrd command. However, this step is performed automatically if the kernel and its associated
packages are installed or upgraded from the RPM packages distributed by Red Hat; in such cases,
you do not need to create the initial RAM disk manually. To verify that an initial RAM disk already
exists, use the command ls -l /boot to make sure the initrd-<version>.img file was created
(the version should match the version of the kernel just installed).
On iSeries systems, the initial RAM disk file and vmlinux file are combined into one file, which is
created with the addRamDisk command. This step is performed automatically if the kernel and its
associated packages are installed or upgraded from the RPM packages distributed by Red Hat,
Inc.; thus, it does not need to be executed manually. To verify that it was created, use the command
ls -l /boot to make sure the /boot/vmlinitrd-<kernel-version> file already exists (the
<kernel-version> should match the version of the kernel just installed).
The next step is to verify that the boot loader has been configured to boot the new kernel. Refer to
Section 40.6, "Verifying the Boot Loader"

40.6. Verifying the Boot Loader

The kernel RPM package configures the boot loader to boot the newly installed kernel (except for
IBM eServer iSeries systems). However, it does not configure the boot loader to boot the new kernel
by default.
It is always a good idea to confirm that the boot loader has been configured correctly. This is a crucial
step. If the boot loader is configured incorrectly, the system will not boot into Red Hat Enterprise Linux
properly. If this happens, boot the system with the boot media created earlier and try configuring the
boot loader again.

40.6.1. x86 Systems

All x86 systems (including all AMD64 systems) use GRUB as the boot loader.
554
for details.
for details.
Section 40.5,