Use real Neutron network for L3 GW by default

Relying on 'external_network_bridge=br-ex' for the L3
agent has been deprecated in Neutron. This patch adjusts
the devstack defaults to setup Neutron in the preferred
manner (empty external_network_bridge value and
correct bridge_mappings for the L2 agent).

This will also help with correct MTU calculations now that
the external network will have the correct segmentation
type on it ('flat' now instead of 'vxlan' by default).

Related-Bug: #1511578
Related-Bug: #1603493
Change-Id: Id20e67aba5dfd2044b82c700f41c6e648b529430

lib/neutron-legacy

@@ -203,7 +203,7 @@ TENANT_VLAN_RANGE=${TENANT_VLAN_RANGE:-}
 # agent, as described below.
 #
 # Example: ``PHYSICAL_NETWORK=default``
-PHYSICAL_NETWORK=${PHYSICAL_NETWORK:-}
+PHYSICAL_NETWORK=${PHYSICAL_NETWORK:-public}
 
 # With the openvswitch agent, if using VLANs for tenant networks,
 # or if using flat or VLAN provider networks, set in ``localrc`` to
@@ -213,7 +213,7 @@ PHYSICAL_NETWORK=${PHYSICAL_NETWORK:-}
 # port for external connectivity.
 #
 # Example: ``OVS_PHYSICAL_BRIDGE=br-eth1``
-OVS_PHYSICAL_BRIDGE=${OVS_PHYSICAL_BRIDGE:-}
+OVS_PHYSICAL_BRIDGE=${OVS_PHYSICAL_BRIDGE:-br-ex}
 
 # With the linuxbridge agent, if using VLANs for tenant networks,
 # or if using flat or VLAN provider networks, set in ``localrc`` to

lib/neutron_plugins/services/l3

@@ -17,6 +17,11 @@ IPV6_PROVIDER_NETWORK_GATEWAY=${IPV6_PROVIDER_NETWORK_GATEWAY:-}
 PUBLIC_BRIDGE=${PUBLIC_BRIDGE:-br-ex}
 PUBLIC_BRIDGE_MTU=${PUBLIC_BRIDGE_MTU:-1500}
 
+# If Q_ASSIGN_GATEWAY_TO_PUBLIC_BRIDGE=True, assign the gateway IP of the public
+# subnet to the public bridge interface even if Q_USE_PROVIDERNET_FOR_PUBLIC is
+# used.
+Q_ASSIGN_GATEWAY_TO_PUBLIC_BRIDGE=${Q_ASSIGN_GATEWAY_TO_PUBLIC_BRIDGE:-True}
+
 # If Q_USE_PUBLIC_VETH=True, create and use a veth pair instead of
 # PUBLIC_BRIDGE.  This is intended to be used with
 # Q_USE_PROVIDERNET_FOR_PUBLIC=True.
@@ -51,7 +56,7 @@ Q_L3_ROUTER_PER_TENANT=${Q_L3_ROUTER_PER_TENANT:-True}
 #    Q_USE_PROVIDERNET_FOR_PUBLIC=True
 #    PUBLIC_PHYSICAL_NETWORK=public
 #    OVS_BRIDGE_MAPPINGS=public:br-ex
-Q_USE_PROVIDERNET_FOR_PUBLIC=${Q_USE_PROVIDERNET_FOR_PUBLIC:-False}
+Q_USE_PROVIDERNET_FOR_PUBLIC=${Q_USE_PROVIDERNET_FOR_PUBLIC:-True}
 PUBLIC_PHYSICAL_NETWORK=${PUBLIC_PHYSICAL_NETWORK:-public}
 
 # Generate 40-bit IPv6 Global ID to comply with RFC 4193
@@ -305,7 +310,7 @@ function _neutron_configure_router_v4 {
             local cidr_len=${FLOATING_RANGE#*/}
             local testcmd="ip -o link | grep -q $ext_gw_interface"
             test_with_retry "$testcmd" "$ext_gw_interface creation failed"
-            if [[ $(ip addr show dev $ext_gw_interface | grep -c $ext_gw_ip) == 0 && ( $Q_USE_PROVIDERNET_FOR_PUBLIC == "False" || $Q_USE_PUBLIC_VETH == "True" ) ]]; then
+            if [[ $(ip addr show dev $ext_gw_interface | grep -c $ext_gw_ip) == 0 && ( $Q_USE_PROVIDERNET_FOR_PUBLIC == "False" || $Q_USE_PUBLIC_VETH == "True" || $Q_ASSIGN_GATEWAY_TO_PUBLIC_BRIDGE == "True" ) ]]; then
                 sudo ip addr add $ext_gw_ip/$cidr_len dev $ext_gw_interface
                 sudo ip link set $ext_gw_interface up
             fi