Open Stack

Hey Matt,

We don't actually have any non-x86 hardware at the moment - we're just 
looking to run certain workloads in qemu full emulation mode sans KVM 
extensions (we know there is a huge performance hit - it's just for a 
few very specific things).  The hosts I'm talking about are normal 
intel-based compute nodes with several different qemu packages installed 
(arm, ppc, mips, x86_64 w/ kvm extensions, etc.).

Is nova designed to work in this kind of scenario?  It seems like many 
pieces are there, but they're just not quite tied together quite right, 
or there is some config option I'm missing.

Thanks!

---
v/r

Chris Apsey
bitskrieg at bitskrieg.net
https://www.bitskrieg.net

On 2018-08-07 09:32 AM, Matt Riedemann wrote:
> On 8/5/2018 1:43 PM, Chris Apsey wrote:
>> Trying to enable some alternate (non-x86) architectures on xenial + 
>> queens.  I can load up images and set the property correctly according 
>> to the supported values 
>> (https://docs.openstack.org/nova/queens/configuration/config.html) in 
>> image_properties_default_architecture.  From what I can tell, the 
>> scheduler works correctly and instances are only scheduled on nodes 
>> that have the correct qemu binary installed.  However, when the 
>> instance request lands on this node, it always starts it with 
>> qemu-system-x86_64 rather than qemu-system-arm, qemu-system-ppc, etc.  
>> If I manually set the correct binary, everything works as expected.
>> 
>> Am I missing something here, or is this a bug in nova-compute?
> 
> image_properties_default_architecture is only used in the scheduler
> filter to pick a compute host, it doesn't do anything about the qemu
> binary used in nova-compute. mnaser added the config option so maybe
> he can share what he's done on his computes.
> 
> Do you have qemu-system-x86_64 on non-x86 systems? Seems like a
> package/deploy issue since I'd expect x86 packages shouldn't install
> on a ppc system and vice versa, and only one qemu package should
> provide the binary.