I was wrong: the alias work ! 
I.e.:

img_hv_type=xyz
 
is equivalent to:

hypervisor_type=xyz

The problem is when xyz is 'qemu'. This used to work with Ocata and now (Rocky) is not working anymore in "my" cloud. It works instead if I use kvm.

This is weird since in

https://docs.openstack.org/nova/rocky/admin/configuration/schedulers.html

it is reported that:

<verbatim>
qemu is used for both QEMU and KVM hypervisor types
</verbatim>

Thanks, Massimo

On Mon, Jul 22, 2019 at 11:16 PM Matt Riedemann <mriedemos@gmail.com> wrote:
On 7/22/2019 4:10 PM, Matt Riedemann wrote:
> Note that the old hypervisor_type image meta key should be translated to
> img_hv_type in the object code:
>
> https://github.com/openstack/nova/blob/d5c67a3d954ddb571645886a23a0f251ae7dd2bb/nova/objects/image_meta.py#L515

In other words, it smells like a nova bug to me that it's not handling
that renamed image property key.

--

Thanks,

Matt