I'm not sure how you're hitting a reschedule because any failures coming out of attach_block_devices should result in the build getting aborted:
https://github.com/openstack/nova/blob/7125dcb9cb821faf3c68526ac34365a28141e480/nova/compute/manager.py#L1682
https://github.com/openstack/nova/blob/7125dcb9cb821faf3c68526ac34365a28141e480/nova/compute/manager.py#L2328
I'm not sure how you're hitting a reschedule because any failures coming out of attach_ block_devices should result in the build getting aborted:
https:/ /github. com/openstack/ nova/blob/ 7125dcb9cb821fa f3c68526ac34365 a28141e480/ nova/compute/ manager. py#L1682
https:/ /github. com/openstack/ nova/blob/ 7125dcb9cb821fa f3c68526ac34365 a28141e480/ nova/compute/ manager. py#L2328