Comment 1 for bug 1746483

Hmm, it appears that the IsolatedHostsFilter doesn't take into account that when you boot from volume, there doesn't need to be an image provided to the server create request, and therefore the RequestSpec likely won't have an image, or at least an image with an id, since the root disk is going to have the volume which has the OS image in it.

 File "/usr/lib/python2.7/dist-packages/nova/scheduler/filters/isolated_hosts_filter.py", line 60, in host_passes#012 image_ref = spec_obj.image.id if spec_obj.image else None