CI: Specify external network by name

Author: mdbooth

test/e2e/data/e2e_conf.yaml

@@ -203,7 +203,8 @@ variables:
   OPENSTACK_IMAGE_NAME_UPGRADE_FROM: "ubuntu-2204-kube-v1.27.2"
   OPENSTACK_NODE_MACHINE_FLAVOR: "m1.small"
   OPENSTACK_SSH_KEY_NAME: "cluster-api-provider-openstack-sigs-k8s-io"
-  OPENSTACK_EXTERNAL_NETWORK_ID: ""
+  # The default external network created by devstack
+  OPENSTACK_EXTERNAL_NETWORK_NAME: "public"
   OPENSTACK_VOLUME_TYPE_ALT: "test-volume-type"
   CONFORMANCE_WORKER_MACHINE_COUNT: "5"
   CONFORMANCE_CONTROL_PLANE_MACHINE_COUNT: "1"

test/e2e/data/kustomize/default/kustomization.yaml

@@ -6,3 +6,14 @@ components:
 - ../common-patches/cni
 - ../upgrade-patches
 - ../common-patches/ccm
+
+patches:
+- patch: |-
+    - op: "remove"
+      path: "/spec/externalNetwork"
+    - op: "add"
+      path: "/spec/externalNetwork"
+      value:
+        name: "${OPENSTACK_EXTERNAL_NETWORK_NAME}"
+  target:
+    kind: OpenStackCluster