@@ -359,6 +359,9 @@ else

     Q_USE_SECGROUP=False

 fi

+default_route_dev=$(ip route | grep ^default | awk '{print $5}')

+die_if_not_set $LINENO default_route_dev "Failure retrieving default route device"

+

 # Save trace setting

 XTRACE=$(set +o | grep xtrace)

 set +o xtrace

@@ -1344,6 +1347,11 @@ function _neutron_configure_router_v6 {

     # This logic is specific to using the l3-agent for layer 3

     if is_service_enabled q-l3; then

+        # Ensure IPv6 RAs are accepted on the interface with the default route.

+        # This is needed for neutron-based devstack clouds to work in

+        # IPv6-only clouds in the gate. Please do not remove this without

+        # talking to folks in Infra.

+        sudo sysctl -w net.ipv6.conf.$default_route_dev.accept_ra=2

         # Ensure IPv6 forwarding is enabled on the host

         sudo sysctl -w net.ipv6.conf.all.forwarding=1

         # Configure and enable public bridge