How to downgrade kernel 6.1 to 6.0 ???

Latest response

Linux deb21kqc 2.6.32-131.2.1.el6.i686 #1 SMP Wed May 18 07:07:27 EDT 2011 i686 i686 i386 GNU/Linux
 

[root@deb21kqc etc]# cat redhat-release
Red Hat Enterprise Linux Server release 6.1 (Santiago)
 

 

is it possible to downgrade to 6.0 ??

if yes, what has to be done, short instruction please, I'm a newbee

you can send directly to juergen.amthauer@siemens.com

 

Jürgen

Responses

Hi Jürgen,
If you are only interested in downgrading the kernel, and nothing else, then it is pretty simple.  Before I provide instructions, let me point out that by downgrading to an older release of the kernel, you are giving up a number of bug fixes, security enhancements, and other improvements.  I recommend seriously evaluating whether a downgrade is really necesssary.  You might want to check the changelog of your current kernel to see the fixes that you'll be giving up by downgrading:

 

  # rpm -q --changelog kernel-$(uname -r)

 

To accomplish what you asked:

 

1) Install the version of the kernel you want to downgrade to.  If you previously updated this system from 6.0 to 6.1, chances are its still installed, since multiple kernel versions can be installed side-by-side and yum leaves up to 3 of them installed on the system at once.  To find out what's already installed, do:

 

   # yum list installed kernel

 

If the version of the kernel you want is *not* installed, then install it with yum:

 

  # yum install kernel-<version>

 

For example, if you want the original kernel version from 6.0:

 

  # yum install kernel-2.6.32-71.el6

 

2) Ensure /boot/grub/grub.conf is configured to boot from the kernel you want.  Look for the 'default=X' line.  grub.conf is separated into entries by lines starting with 'title', and the first entry is #0, second is #1, etc.  For example:

 

default=0
timeout=5
splashimage=(hd0,0)/grub/splash.xpm.gz
hiddenmenu
title Red Hat Enterprise Linux Server (2.6.32-125.el6.x86_64)
    root (hd0,0)
    kernel /vmlinuz-2.6.32-125.el6.x86_64 ro root=/dev/mapper/vg_jrummy-lv_root rd_LVM_LV=vg_jrummy/lv_root rd_LVM_LV=vg_jrummy/lv_swap rd_NO_LUKS rd_NO_MD rd_NO_DM LANG=en_US.UTF-8 SYSFONT=latarcyrheb-sun16 KEYBOARDTYPE=pc KEYTABLE=us crashkernel=auto console=tty0 console=ttyS0 crashkernel=auto rhgb
    initrd /initramfs-2.6.32-125.el6.x86_64.img
title Red Hat Enterprise Linux Server (2.6.32-71.7.1.el6.x86_64)
    root (hd0,0)
    kernel /vmlinuz-2.6.32-71.7.1.el6.x86_64 ro root=/dev/mapper/vg_jrummy-lv_root rd_LVM_LV=vg_jrummy/lv_root rd_LVM_LV=vg_jrummy/lv_swap rd_NO_LUKS rd_NO_MD rd_NO_DM LANG=en_US.UTF-8 SYSFONT=latarcyrheb-sun16 KEYBOARDTYPE=pc KEYTABLE=us crashkernel=auto console=tty0 console=ttyS0 crashkernel=auto rhgb
    initrd /initramfs-2.6.32-71.7.1.el6.x86_64.img

 

In this example, default=0 is pointing at the entry for kernel-2.6.32-125.el6, since it is the first in the file.  Change the default line to point to whichever kernel you wish to boot to.

 

3) Reboot.  Since you configured grub.conf to default to the kernel you want, it should automatically boot into the right one.  You can also use the keyboard arrows to select a different kernel in the grub menu than the default. 

 

Let me know if you have any questions.

 

Regards,
John Ruemker, RHCA
Red Hat Technical Account Manager
Online User Groups Moderator
 

Well written, John. I didn't know about the rpm --changelog option until reading your response.

Agreed very well written and I also had not known about rpm -q --changelog. Will definitely be using that one now.

hi John , what about /etc/redhat-release , it still shows as 6.1 not 6.0

Because you have only downgraded the kernel. You can downgrade that file with the redhat-release* package.

 

# rpm -qa | grep release

redhat-release-server-6Server-6.0.0.37.el6.i686

# rpm -ql redhat-release-server-6Server | grep redhat-release

/etc/pki/rpm-gpg/RPM-GPG-KEY-redhat-release

/etc/redhat-release

/usr/share/doc/redhat-release-server-6Server

/usr/share/doc/redhat-release-server-6Server/EULA

/usr/share/doc/redhat-release-server-6Server/GPL

/usr/share/doc/redhat-release-server-6Server/autorun-template

 

So you can use the great write up above to essentially do the same thing for downgrading 6.1 to 6.0 of the redhat-release file. Note that even after downgrading the kernel and the redhat-release, you still have not entirely downgraded to 6.0. Any package updates, at the least, provided in 6.1 would also need to be rolled back to obtain a true 6.0 downgrade.

This document was posted yesterday to access site ..http://people.redhat.com/rprice/yum_history.txt

 

It shows how to undo your rpm.

Don't do 'yum history undo' on a history that upgraded the whole box from RHEL6.0 to RHEL6.1.  If it's a simple 'yum update kernel', then sure, but a whole minor release could render you box broken.

 

~rp