To enable support for the L2 population driver, the l2_population configuration option must be set to true. Update the l2_population configuration option in the [vxlan] section of the ML2 configuration file accordingly on controller01 and compute01:

[vxlan]
...
l2_population = true

A useful feature of the L2 population driver is its ARP responder functionality that helps avoid the broadcasting of ARP requests across the overlay network. Each compute node can proxy ARP requests from virtual machines and provide them with replies, all without that traffic leaving the host.

To enable the ARP responder, update the following configuration option:

[vxlan]
...
arp_responder = true

The ARP responder has known incompatibilities with the allowed-address-pairs extension on systems using the Linux bridge agent, however. The vxlan kernel module utilized by the Linux bridge agent does not support dynamic learning when ARP responder functionality is enabled. As a result, when an IP address moves between virtual machines, the forwarding database may not be updated with the MAC address and respective VTEP of the destination host as Neutron is not notified of this change. If allowed-address-pairs functionality is required, my recommendation is to disable the ARP responder until this behavior is changed.