Fix MetalLB L2Advertisement to use baremetal network interface only

Author: zhfeng

ci-operator/step-registry/hypershift/kubevirt/baremetalds/metallb/hypershift-kubevirt-baremetalds-metallb-commands.sh

@@ -5,6 +5,17 @@ set -o errexit
 set -o pipefail
 set -x
 
+POOL_RANGE="192.168.111.30-192.168.111.50"
+
+# Pin L2 announcements to the baremetal network interface only.
+# Without this, extra network interfaces (e.g. from nmstate) can cause
+# MetalLB speakers to announce VIPs on the wrong interface, making
+# LoadBalancer IPs unreachable from the infra cluster.
+# In OVN environments, the baremetal network (192.168.111.0/24) is on
+# br-ex (OVS external bridge), not on the raw NIC. enp1s0 is the
+# provisioning network (172.22.0.0/24), enp2s0 is consumed by OVS.
+METALLB_IFACE="br-ex"
+
 oc create -f - <<EOF
 apiVersion: metallb.io/v1beta1
 kind: MetalLB
@@ -21,7 +32,7 @@ metadata:
   namespace: metallb-system
 spec:
   addresses:
-  - 192.168.111.30-192.168.111.50
+  - ${POOL_RANGE}
 EOF
 
 oc create -f - <<EOF
@@ -33,4 +44,6 @@ metadata:
 spec:
   ipAddressPools:
    - metallb
+  interfaces:
+   - ${METALLB_IFACE}
 EOF