Friday, March 5, 2010

REDHAT: To Test New Kernel Reboot Once

We want to change default=0 to default=1 This will boot your old kernel (not the upgraded one). Grub starts at 0, which will be your new kernel. We will switch to the new kernel later.

Save and exit.

Step 3: Configure server to boot once with the new kernel.

Now we will configure the server to boot the new kernel only once in case it fails. This is the most important step, if its not done and the new kernel fails your out of luck.

Type the following from command line (one at a time):

savedefault --default=0 --once

Step 4 – Reboot

Then reboot the server or computer. When it comes back up run uname -a to make sure it has the new kernel. (Note: if it does not come back up, reboot it again and it will load the old kernel.)

Then switch the grub.conf to boot the new kernel permanently.

nano /boot/grub/grub.conf

change default=1 to default=0

Save and exit. Thats it you have successfully updated your kernel.