How to downgrade a kernel?

Question

I need to downgrade the kernel from 2.6.32-358.6.2.el6.centos.plus.x86_64 to 2.6.32-220.el6.x86_64

I am unable to install the older version using Yum/rpm as it gives the following error

root@localhost kernels]# rpm -i --ignoreos kernel-2.6.32-220.el6.x86_64.rpm 
warning: kernel-2.6.32-220.el6.x86_64.rpm: Header V4 DSA/SHA1 Signature, key ID  
192a7d7d: NOKEY
package kernel-2.6.32-279.el6.x86_64 (which is newer than kernel-2.6.32-220.el6.x86_64) is already installed
package kernel-2.6.32-358.6.1.el6.centos.plus.x86_64 (which is newer than kernel-2.6.32-220.el6.x86_64) is already installed
package kernel-2.6.32-358.6.2.el6.centos.plus.x86_64 (which is newer than kernel-2.6.32-220.el6.x86_64) is already installed

I cant remove the currently running kernel , so whats the way out?

Yum search doesnt even get me to this old version, so had to get the rpm from web.

Any help is much appreciated.

Solution 1

rpm -ivh <kernel.rpm> --oldpackage does the job in centos

This will install your kernel, now make sure the grub entries are proper and then you can reboot and boot into this kernal

Solution 2

Actually, downgrade wouldn't work for kernel. The right command would be localinstall:

#yum localinstall ./kernel....rpm

If you have more then 5 kernels yum will delete oldest.

Comments

[LawrenceC]

I don't have a lot of experience with rpm but can't you remove the current kernel package and then install the lower version one? The kernel isn't actually in effect until your reboot next. I'm not sure if CentOS/Redhat does this, but in Debian, when you upgrade your kernel with a kernel package, the previous kernel can be selected in the bootloader still. You might be able to do this too.

[Ignacio Vazquez-Abrams]

@ultrasawblade: There's no need to remove the old kernel. Fedora-based distros allow multiple kernel packages to be installed; the trick is to use -i (instead of -U) and --oldpackage.

[cybernard]

@JATMON Actually what you need to do is get a linux with a modern kernel version. The current version is 3.9.6 your centos version is using an ancient kernel.