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On Wed, Aug 23, 2017 at 10:54 AM, Markus Zoeller
<mzoeller at linux.vnet.ibm.com> wrote:
> On 23.08.2017 14:47, Brian Rosmaita wrote:
>> 'architecture' is one of the "common image properties" that was
>> introduced in Folsom in an effort to standardize use of image
>> metadata.  It's not a mistake in the Glance docs, it's just that Nova
>> is looking for a differently named property.
>>
>> Glance has had a metadata definitions service [0,1] since Juno.  It
>> provides a common API for vendors, admins, services, and users to
>> meaningfully define available key / value pair metadata that can be
>> used on different types of resources (images, artifacts, volumes,
>> flavors, aggregates, and other resources). A definition includes a
>> property’s key, its description, its constraints, and the resource
>> types to which it can be associated.  It's probably a better place to
>> store this kind of information than in documentation.  I think it's
>> under-utilized.
>>
>> [0] https://developer.openstack.org/api-ref/image/v2/metadefs-index.html
>> [1] https://docs.openstack.org/glance/latest/user/metadefs-concepts.html
>
>
> OK, I agree that the information to do it right is available:
>
>     "The keys have different prefixes on images than on flavors.
>     On flavors keys are prefixed with hw:, but on images the keys
>     are prefixed with hw_."
>
> It's just not *that* easy to find and to deduct. I was looking for that
> information as an operator, to allow the Nova scheduler to do its work
> in a mixed arch environment (x86 + s390x) based on image properties.
>
> I still don't fully get it. In which use-case is `architecture` the
> correct property to set?

It depends on what you mean by "correct". If you're just describing
what's in the image, it works fine.  If you expect it to actually do
something, then you need to use the hw_ one.

My point is just that Glance went one way on this, Nova went a
different way, and users are left hanging.  My secondary point is that
it might be useful to catalog these things in the metadata definitions
service so that we all stay on the same page better.

cheers,
brian

> Regards, Markus Zoeller (markus_z)
>
>> On Wed, Aug 23, 2017 at 5:45 AM, Markus Zoeller
>> <mzoeller at linux.vnet.ibm.com> wrote:
>>> On 22.08.2017 17:10, Markus Zoeller wrote:
>>>> I'm wondering if there is an issue in the docs which describe the
>>>> possible image metadata properties:
>>>> https://docs.openstack.org/python-glanceclient/latest/cli/property-keys.html#
>>>>
>>>> This document says to use `architecture` (e.g. x86_64 or s390x or ppc64)
>>>> but the Nova scheduler image properties filter uses `hw_architecture`
>>>> (note the *hw_* prefix):
>>>> https://github.com/openstack/nova/blob/4a7502a5c9e84a8c8cef7f355d72425b26b8c379/nova/scheduler/filters/image_props_filter.py#L44
>>>>
>>>> Is that simply a mistake in the Glance docs or do I miss some kind of
>>>> conversion between those metadata keys?
>>>>
>>>
>>> Looks like only `hw_architecture` works in my x86 + s390x environment.
>>> I'm going to push an update to the Glance docs + an update to the
>>> `os_image` Ansible module which uses `cpu_arch` in its documentation:
>>> http://docs.ansible.com/ansible/latest/os_image_module.html
>>>
>>> --
>>> Regards, Markus Zoeller (markus_z)
>>>
>>>
>
>
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