[BGP] Add AZs to schedule Octavia mgmt network on OCP nodes

Octavia needs to schedule its management network on the OCP
nodes/workers.
With BGP, OCP nodes/workers should not be used to schedule OVN router
ports.
In order to resolve this conflict, this patch uses Availability Zones.

dt/bgp/kustomization.yaml

@@ -209,6 +209,18 @@ replacements:
         options:
           create: true
 
+  - source:
+      kind: ConfigMap
+      name: service-values
+      fieldPath: data.octavia.availabilityZones
+    targets:
+      - select:
+          kind: OpenStackControlPlane
+        fieldPaths:
+          - spec.octavia.template.availabilityZones
+        options:
+          create: true
+
   - source:
       kind: ConfigMap
       name: service-values

examples/dt/bgp/bgp_dt01/README.md

@@ -37,6 +37,13 @@ This DT configures both compute and networker EDPM nodes. So far, networker
 nodes are needed when BGP is used on RHOSO, in order to expose routes to SNAT
 traffic (OVN Gateway IPs). In other words, when RHOSO is used with BGP, the OCP
 workers cannot be configured as OVN Gateways.
+On the other hand, Octavia needs to use OCP workers as OVN Gateways for
+its management network.
+To resolve this conflict, BGP DT01 uses Availability Zones:
+* zone-1 is only used for the Octavia management network, which is scheduled on
+  the OCP workers
+* zone-2 is used for the provider networks, whose routers ports will be
+  scheduled on the networker nodes.
 
 The OCP and EDPM nodes deployed with this DT are distributed into three
 different racks. Each rack is connected to two leaves.
@@ -74,14 +81,14 @@ network).
 
 ## Services, enabled features and configurations
 
-| Service          | configuration    | Lock-in coverage?  |
-| ---------------- | ---------------- | ------------------ |
-| Glance           | Swift            | Must have          |
-| Swift            | (default)        | Must have          |
-| Octavia          | (default)        | Must have          |
-| Heat             | (default)        | Must have          |
-| frr              | dataplane        | Must have          |
-| ovn-bgp-agent    | dataplane        | Must have          |
+| Service          | configuration     | Lock-in coverage?  |
+| ---------------- | ----------------- | ------------------ |
+| Glance           | Swift             | Must have          |
+| Swift            | (default)         | Must have          |
+| Octavia          | (default)         | Must have          |
+| Heat             | (default)         | Must have          |
+| frr              | dataplane         | Must have          |
+| ovn-bgp-agent    | dataplane         | Must have          |
 
 ## Considerations/Constraints
 

examples/dt/bgp/bgp_dt01/control-plane/kustomization.yaml

@@ -144,16 +144,16 @@ replacements:
           name: bgpnet-worker-3
         fieldPaths:
           - spec.config
-  # disable OCP workers as gateway nodes
+  # configure OVN AZs
   - source:
       kind: ConfigMap
       name: service-values
-      fieldPath: data.ovn.ovnController.external-ids
+      fieldPath: data.ovn.ovnController.availability-zones
     targets:
       - select:
           kind: OpenStackControlPlane
         fieldPaths:
-          - spec.ovn.template.ovnController.external-ids
+          - spec.ovn.template.ovnController.availability-zones
         options:
           create: true
   # configure neutron customServiceConfig

examples/dt/bgp/bgp_dt01/control-plane/service-values.yaml

@@ -30,6 +30,8 @@ data:
     enabled: true
     amphoraImageContainerImage: quay.io/gthiemonge/octavia-amphora-image
     apacheContainerImage: registry.redhat.io/ubi9/httpd-24:latest
+    availabilityZones:
+      - zone-1
     octaviaAPI:
       networkAttachments:
         - internalapi
@@ -60,12 +62,15 @@ data:
       nicMappings:
         datacentre: ocpbr
         octavia: octbr
-      external-ids:
-        enable-chassis-as-gateway: false
+      availability-zones:
+        - zone-1
   neutron:
     customServiceConfig: |
       [DEFAULT]
       vlan_transparent = true
       debug = true
+      default_availability_zones = zone-1,zone-2
       [ovs]
       igmp_snooping_enable = true
+      [ovn]
+      ovn_emit_need_to_frag = true

examples/dt/bgp/bgp_dt01/edpm/networkers/values.yaml

@@ -21,6 +21,8 @@ data:
       ansiblePort: 22
       ansibleVars:
         edpm_ovn_encap_ip: "{{ lookup('vars', 'bgpmainnet_ip') }}"
+        edpm_ovn_availability_zones:
+          - zone-2
         edpm_ovn_bgp_agent_expose_tenant_networks: false
         edpm_frr_bgp_ipv4_src_network: bgpmainnet
         edpm_frr_bgp_ipv6_src_network: bgpmainnetv6