How to switch to a generic kernel in a headless Ubuntu Server 12.04?
I just got a dedicated server with Ubuntu 12.04 installed with a custom compiled kernel. Since I would like to install VirtualBox and this custom kernel doesn't support dynamic module loading (for security) I need to change the kernel.
I'm running some Ubuntu servers for years but never played with grub and a headless computer.
When the command update-grub is run it shows the different kernel it finds. Here is what I see
Generating grub.cfg ...
Found linux image: /boot/bzImage-3.2.13-xxxx-grs-ipv6-64
Found linux image: /boot/vmlinuz-3.2.0-34-generic
Found initrd image: /boot/initrd.img-3.2.0-34-generic
No volume groups found
done
The first one is the active one as seen with uname -r
. To me it looks like the second kernel is the one I should use. But I don't know how to configure grub2 to use it.
The computer is also configured with a software RAID using mdadm I guess. Never used that before. I don't know if playing with the grub of changing kernel could brake this.
What must I do to set the generic kernel as the default one so that I can get VirtualBox running.
Solution 1:
To change the default menu entry from a terminal:
- Obtain the existing
menuentry
choice number (starting from 0) run the following from the terminal:grep menuentry /boot/grub/grub.cfg
- Now open
/etc/default/grub
as root then updateGRUB_DEFAULT
to the corresponding menuentry number. - Run
sudo update-grub
- Reboot !