[ubuntu-cloud] EC2, "2.6.32-21-server" kernel instead of "2.6.32-305-ec2"?

Scott Moser smoser at ubuntu.com
Tue Aug 17 14:06:53 BST 2010

On Mon, 16 Aug 2010, Jack Bates wrote:

> When I run the EC2 image "ami-fd4aa494", it boots kernel
> "2.6.32-305-ec2",
> $ uname -r
> 2.6.32-305-ec2
> $
> However kernel "2.6.32-21-server" is also installed,
> $ ls /boot/vmlinuz-*
> /boot/vmlinuz-2.6.32-21-server  /boot/vmlinuz-2.6.32-305-ec2
> $
> How do I boot from this other kernel instead?

In 10.04, the -server kernel that is also installed is not usable on EC2.
The kernel is present there to aid in moving to UEC if you so desired.
UEC uses kvm and full virtualization rather than xen/paravirt.

on 10.04 and EC2, you could safely remove that kernel if you wanted.

On 10.10 (maverick/the current development release), you will both be able
to boot the -virtual kernel, and will by default.  Maverick images use the
pv-grub loader recently released by amazon, and use a pv-ops kernel, so
one kernel can run on xen or on kvm (or actually "bare metal").

We've still got some work to get there, but I'm really happy with the
prospect of using a single kernel in our images, and using a pv-grub to
allow 'apt-get upgrade' to install a new kernel and a reboot into it.


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