Due to a limitation in the OpenStack Networking service, the Distributed Virtual Router (DVR) in combination with L3 HA is not stable enough and affects the SNAT traffic. Therefore, Mirantis does not recommend such a configuration for production deployments.
Instead of L3 HA, the allow_automatic_l3agent_failover option is enabled
by default in neutron.conf for the Neutron OVS with DVR deployments in MCP.
This option enables automatic rescheduling of a failed L3 agent routers
to an online L3 agent on a different network node.