Add support for configuring unbound forwarders

This patch adds support for unbound forwarders configuration.
The end user / operator should create a configmap similar to
the one on demo/examples and the forwarder files will be mounted
in the unbound pod.

demo/examples/unbound_forwarder_example.yaml

@@ -0,0 +1,15 @@
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: designate-unbound-forwarders-config
+data:
+  forwarders.conf: |
+    forward-zone:
+      name: "."
+      forward-addr: 8.8.8.8
+      forward-addr: 8.8.4.4
+  other.conf: |
+    forward-zone:
+      name: "."
+      forward-addr: 8.8.8.8
+      forward-addr: 8.8.4.4

pkg/designateunbound/statefulset.go

@@ -16,6 +16,8 @@ limitations under the License.
 package designateunbound
 
 import (
+	"fmt"
+
 	designatev1beta1 "github.com/openstack-k8s-operators/designate-operator/api/v1beta1"
 	designate "github.com/openstack-k8s-operators/designate-operator/pkg/designate"
 	common "github.com/openstack-k8s-operators/lib-common/modules/common"
@@ -28,36 +30,15 @@ import (
 	"k8s.io/utils/ptr"
 )
 
-const (
-	configVolume = "designateunbound-config"
-)
-
 // StatefulSet func
 func StatefulSet(instance *designatev1beta1.DesignateUnbound,
 	configHash string,
 	labels map[string]string,
 	annotations map[string]string,
 ) *appsv1.StatefulSet {
-	var configMode int32 = 0640
-
-	volumes := []corev1.Volume{
-		{
-			Name: configVolume,
-			VolumeSource: corev1.VolumeSource{
-				Secret: &corev1.SecretVolumeSource{
-					DefaultMode: &configMode,
-					SecretName:  "designate-unbound-config-data",
-				},
-			},
-		},
-	}
-	mounts := []corev1.VolumeMount{
-		{
-			Name:      configVolume,
-			MountPath: "/etc/unbound/conf.d",
-			ReadOnly:  true,
-		},
-	}
+	serviceName := fmt.Sprintf("%s-unbound", designate.ServiceName)
+	volumes := GetVolumes(serviceName)
+	volumeMounts := GetVolumeMounts()
 
 	livenessProbe := &corev1.Probe{
 		// TODO might need tuning
@@ -126,7 +107,7 @@ func StatefulSet(instance *designatev1beta1.DesignateUnbound,
 							RunAsUser: ptr.To[int64](0),
 						},
 						Env:            env.MergeEnvs([]corev1.EnvVar{}, envVars),
-						VolumeMounts:   mounts,
+						VolumeMounts:   volumeMounts,
 						Resources:      instance.Spec.Resources,
 						ReadinessProbe: readinessProbe,
 						LivenessProbe:  livenessProbe,

pkg/designateunbound/volumes.go

@@ -0,0 +1,67 @@
+/*
+Copyright 2025.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+    http://www.apache.org/licenses/LICENSE-2.0
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package designateunbound
+
+import (
+	corev1 "k8s.io/api/core/v1"
+)
+
+const (
+	configVolume           = "designateunbound-config"
+	forwardersConfigVolume = "designateunbound-forwarders-config"
+)
+
+func GetVolumes(baseConfigMapName string) []corev1.Volume {
+	var configMode int32 = 0640
+	forwardersConfigOptional := true
+
+	return []corev1.Volume{
+		{
+			Name: configVolume,
+			VolumeSource: corev1.VolumeSource{
+				Secret: &corev1.SecretVolumeSource{
+					SecretName:  baseConfigMapName + "-config-data",
+					DefaultMode: &configMode,
+				},
+			},
+		},
+		{
+			Name: forwardersConfigVolume,
+			VolumeSource: corev1.VolumeSource{
+				ConfigMap: &corev1.ConfigMapVolumeSource{
+					LocalObjectReference: corev1.LocalObjectReference{
+						Name: baseConfigMapName + "-forwarders-config",
+					},
+					Optional:    &forwardersConfigOptional,
+					DefaultMode: &configMode,
+				},
+			},
+		},
+	}
+}
+
+func GetVolumeMounts() []corev1.VolumeMount {
+	return []corev1.VolumeMount{
+		{
+			Name:      configVolume,
+			MountPath: "/etc/unbound/conf.d",
+			ReadOnly:  true,
+		},
+		{
+			Name:      forwardersConfigVolume,
+			MountPath: "/etc/unbound/conf.d/forwarders",
+			ReadOnly:  true,
+		},
+	}
+}