Comment 2 for bug 1663304

copied from my response on the cloud-init mailing list:

When this was added, OpenStack was incapable of identifying itself on
non-x86 architectures[1]. The workaround, as you found, was to assume
Openstack is a possible datasource, and pass responsibility to cloud-init.
This unfortunately means that, yes, openstack is assumed on all non-x86
architectures. DMI support on aarch64 has since made its way upstream[2],
however I don't think that anyone has gotten around to verifying whether
OpenStack correctly passes this information through Libvirt.

It looks like Libvirt is aware of aarch64 support for SMBIOS[3], but it doesn't
seem like nova is aware of this yet[4]. I don't know how to go about getting
this fixed, but I naively hope that the attached patch might be a step in the
right direction.

[1] https://bugs.launchpad.net/cloud-init/+bug/1663304
[2] https://bugs.launchpad.net/bugs/1662345
[3] https://github.com/libvirt/libvirt/commit/ec6ce6363a78aaaf6e3aa4c0e2d683d7d0cce183
[4] https://github.com/openstack/nova/blob/db9351ab5191e058994209464aa7fc2b2fa34561/nova/virt/libvirt/driver.py#L6856