Category Archives: kernel

How to change OVH kernel to normal Centos kernel

I’ve just installed new OVH serwer on Centos 6.3. And I spotted a problem – I couldn’t install KVM services due to lack of KVM kernel modules. And I wasn’t abe to load them because this fresh installation used some OVH kernel which was wiped out of those modues…

So I had two ways of solving this issue. Recompiling kernel from scratch and adding KVM modules (long way – and what for? It just consumes so much time…) or.. just revert stock Centos kernel :) And this was the way I chose.

Whole procedure is just trivial. Firsth thing – let’s install new kernel (stok one) with yum::

When installed, we need to include it in the boot loader – which is Grub by default in Centos. In order to do it properly, we have to know our kernel version (so this one we’re given after yum install kernel command, so: kernel-2.6.32-279.19.1.el6.x86_64 in my case and the device, which hosts our root partition – we can check this with mount command and the contents of /etc/fstab directory:

Above we see that / directory is hosted on /dev/md1 device. So now we can modify /boot/grub/grub.conf:

Now after double-check we just reboot our system and wait.. If it’s up then let’s be sure, that we got our stock centos kernel:

So we’re good :) If for some reason server is not coming back after reboot then We can rescue it by booting it into rescue-mode in OVH manager. Then we need to replace /boot/grub/grub.conf with our backup /boot/grub/grub.conf.bak