Centos 5 Kernel Update

[ongch]

1) May i know how to update the kernel?
2) And how to keep the existing kernel ?
3) In case anything happen, how do i can restore back the existing kernel?

[davidanand]

hello you can update your kernal via yum
and you have to change the grub which kernal to load and restart the
box ... that will do...

[Roxoff]

If you run 'yum update' it will bring in all the latest changes to your operating system released by the CentOS team, including new kernels.

When you boot, grub will give you a list of the kernels available so you can pick which one you want. The new one will be at the top of the list and be the default selection, but you can select any other you have installed.