For those who still haven't heard of cloud-provider-openstack[1], cloud-provider-openstack is an implementation of Kubernetes Cloud Controller Manager[2], it's a sub-project under Kubernetes, which provides a couple of binaries/services relevant to OpenStack and Kubernetes integration, more documentation could be found here[3].
The demo below shows how to migrate from in-tree openstack cloud provider to external openstack-cloud-controller-manager. The Kubernetes cluster in the demo was set up using kubeadm.