operator: bug fix where dots in the node name broke the app

internal/controller/overlay_controller.go

@@ -199,7 +199,7 @@ func (r *OverlayReconciler) createExternalResources(ctx context.Context, overlay
 		for _, nodeName := range overlay.Spec.Topology.Nodes {
 			node := switchv1.Node{
 				Name:   nodeName,
-				NodeIP: fmt.Sprintf("l2sm-switch-%s-%s", overlayName, nodeName),
+				NodeIP: utils.GenerateServiceName(overlayName, nodeName),
 			}
 			topologySwitch.Nodes = append(topologySwitch.Nodes, node)
 		}
@@ -371,7 +371,7 @@ func (r *OverlayReconciler) createExternalResources(ctx context.Context, overlay
 			// Create a headless service for the ReplicaSet
 			service := &corev1.Service{
 				ObjectMeta: metav1.ObjectMeta{
-					Name:      fmt.Sprintf("l2sm-switch-%s-%s", overlay.Name, node),
+					Name:      utils.GenerateServiceName(overlay.Name, node),
 					Namespace: overlay.Namespace,
 					Labels:    map[string]string{"app": name},
 				},

internal/utils/utils.go

@@ -20,6 +20,7 @@ import (
 	"crypto/sha256"
 	"encoding/hex"
 	"fmt"
+	"hash/fnv"
 	"strings"
 
 	"k8s.io/apimachinery/pkg/runtime"
@@ -133,3 +134,11 @@ func GetBridgeName(params BridgeParams) string {
 	dpid := hex.EncodeToString(dpidBytes)
 	return fmt.Sprintf("br-%s", dpid)
 }
+
+func GenerateServiceName(overlayName, nodeName string) string {
+	hash := fnv.New32() // Using FNV hash for a compact hash, but still 32 bits
+	hash.Write([]byte(fmt.Sprintf("%s%s", overlayName, nodeName)))
+	sum := hash.Sum32()
+	// Encode the hash as a base32 string and take the first 4 characters
+	return fmt.Sprintf("l2sm-switch-%04x", sum) // H
+}