In the following screenshot, an HA router without any connected gateway or project networks is scheduled across three L3 agents running on a single controller and two compute nodes:
The Neutron L3 agent is commonly installed on controller or network nodes, but can be installed on compute nodes as well. This is especially true when distributed virtual routers are configured.
In the preceding example, one router acts as the master while the other two are relegated to backup duties. The HA interfaces are used for communication between the routers. At any given time, only the master router should have the virtual IP address 169.254.0.1 configured on its HA interface.