As per our discussion and testing, this is a request to implement support for ha_chassis_group for OVN logical routers. The idea is to have a native support for HA when CMS wants to bind routers to a subset of chassis. This will be useful for example when external network is of the Geneve type. This feature is mutually exclusive to https://issues.redhat.com/browse/FDP-364 , so it's either that or this.