StarCluster - Mailing List Archive

Re: [Starcluster] Version of StartCluster with support for Amazon Cluster Compute Images

From: Justin Riley <no email>
Date: Mon, 13 Sep 2010 11:56:15 -0400

On 09/13/2010 09:40 AM, Austin Godber wrote:
> So, were my instructions for creating HVM based images inaccurate? I
> had thought that HVM and the cluster compute type posed two separate
> issues. HVM works, but cluster compute images don't do to lack of
> support (for something) in the kernel.

I could be wrong but I believe the instructions you have are for
PVM-based images where you assign the image's AKI/ARI to a pv_grub
kernel/ramdisk. That pvm-grub kernel will then load your kernel from the
EBS root device using your EBS root device's /boot/grub/menu.lst.

The Cluster Compute works similarly, however, if you look at the Cent OS
HVM Cluster Compute reference image you'll see that it doesn't have an
AKI/ARI at all. I believe the HVM image instead loads Grub from the EBS
volume (rather then using the pv_grub AKI/ARI) and then uses stock Grub
to launch the kernel.

Also HVM kernels need high-performance pv drivers[0] in order to use
ephemeral stores and attached EBS vols[1]. Unfortunately when I applied
the patches, compiled, and tested the pv modules against a 2.6.32 kernel
I still couldn't get the resulting kernel to load (no console output
even!). I couldn't just use the 2.6.18 kernel from the reference image
(although I tried) since Ubuntu *has* to have a recent kernel otherwise
there are issues. So, I gave up on this for now until I have more time
to figure out what's needed to get a 2.6.32 kernel to launch on Cluster
Compute HVM machines.

In short, I think your instructions are for PVM and are identical to the
HVM process except that there's no AKI/ARI to assign and the kernel you
use with Cluster Compute HVM needs to be configured with the proper pv
modules from the Xen post[0].

Also, the EC2 dev docs state that user-provided/PVM kernel AMIs will not
work with the new Cluster Compute instance type:

[1]"Cluster compute instances require the use of HVM-based, Amazon
EBS-backed AMIs. Paravirtual (PV) AMIs employed by Linux instances or
other EC2 instance types that use paravirtual machine (PVM)-based
virtualization are not supported. Cluster compute instances do not
require the use of Amazon Kernel Images (AKIs) or Amazon RAMdisk Images
(ARIs) that are part of PVM-based AMIs used with other EC2 instance types."



Received on Mon Sep 13 2010 - 11:56:22 EDT
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