Since k8s 1.9 Openstack cloud-provider support a pretty useful settings named "ignore-volume-az".
When Nova and Cinder have different availability zones, this should be set to true. This is most commonly the case where there are many Nova availability zones but only one Cinder availability zone.
As per k8s documentation this is set to false.
We have created an issue in Pivotal Tracker to manage this:
The labels on this github issue will be updated when the story is started.