In the MCP 2019.2.9 maintenance update, Mirantis introduces the following enhancements for OpenStack:
To obtain the enhancements, follow the steps described in Apply maintenance updates.
Added support for HA with availability zones for Neutron to provide an extra layer of protection by segmenting the Neutron service deployment in isolated failure domains. By deploying HA nodes across different availability zones, the network services remain available in case of zone-wide failures affecting the deployment. If required, you can manually enable Cross-AZ high availability for DHCP and L3 routers.