Add flag to support ClusterIP exposed CoreDNS

controllers/depresolver/depresolver.go

@@ -144,6 +144,8 @@ type Config struct {
 	Infoblox Infoblox
 	// CoreDNSExposed flag
 	CoreDNSExposed bool `env:"COREDNS_EXPOSED, default=false"`
+	// CoreDNSClusterIPs flag
+	CoreDNSClusterIPs bool `env:"COREDNS_CLUSTERIPS, default=false"`
 	// Log configuration
 	Log Log
 	// MetricsAddress in format address:port where address can be empty, IP address, or hostname, default: 0.0.0.0:8080

controllers/providers/assistant/assistant.go

@@ -25,6 +25,8 @@
 )
 
 type Assistant interface {
+	//CoreDNSClusterIPs retrieves a list of ClusterIPs assigned to CoreDNS
+	CoreDNSClusterIPs() ([]string, error)
 	// CoreDNSExposedIPs retrieves list of exposed IP by CoreDNS
 	CoreDNSExposedIPs() ([]string, error)
 	// GetExternalTargets retrieves slice of targets from external clusters

controllers/providers/assistant/gslb.go

@@ -58,8 +58,7 @@ func NewGslbAssistant(client client.Client, k8gbNamespace string, edgeDNSServers
 	}
 }
 
-// CoreDNSExposedIPs retrieves list of IP's exposed by CoreDNS
-func (r *Gslb) CoreDNSExposedIPs() ([]string, error) {
+func (r *Gslb) GetCoreDNSService() (*corev1.Service, error) {
 	serviceList := &corev1.ServiceList{}
 	sel, err := labels.Parse(coreDNSServiceLabel)
 	if err != nil {
@@ -88,7 +87,32 @@ func (r *Gslb) CoreDNSExposedIPs() ([]string, error) {
 		return nil, err
 	}
 	coreDNSService := &serviceList.Items[0]
+	return coreDNSService, nil
+}
 
+// CoreDNSClusterIPs retrieves list of ClusterIPs assigned to CoreDNS
+func (r *Gslb) CoreDNSClusterIPs() ([]string, error) {
+	coreDNSService, err := r.GetCoreDNSService()
+	if err != nil {
+		return nil, err
+	}
+	if len(coreDNSService.Spec.ClusterIPs) == 0 {
+		errMessage := "no ClusterIPs found"
+		log.Warn().
+			Str("serviceName", coreDNSService.Name).
+			Msg(errMessage)
+		err := coreerrors.New(errMessage)
+		return nil, err
+	}
+	return coreDNSService.Spec.ClusterIPs, nil
+}
+
+// CoreDNSExposedIPs retrieves list of IP's exposed by CoreDNS
+func (r *Gslb) CoreDNSExposedIPs() ([]string, error) {
+	coreDNSService, err := r.GetCoreDNSService()
+	if err != nil {
+		return nil, err
+	}
 	var lb corev1.LoadBalancerIngress
 	if len(coreDNSService.Status.LoadBalancer.Ingress) == 0 {
 		errMessage := "no LoadBalancer ExternalIPs are found"

controllers/providers/dns/external.go

@@ -66,7 +66,11 @@ func (p *ExternalDNSProvider) CreateZoneDelegationForExternalDNS(gslb *k8gbv1bet
 	var NSServerIPs []string
 	var err error
 	if p.config.CoreDNSExposed {
-		NSServerIPs, err = p.assistant.CoreDNSExposedIPs()
+		if p.config.CoreDNSClusterIPs {
+			NSServerIPs, err = p.assistant.CoreDNSClusterIPs()
+		} else {
+			NSServerIPs, err = p.assistant.CoreDNSExposedIPs()
+		}
 	} else {
 		if len(gslb.Status.LoadBalancer.ExposedIPs) == 0 {
 			// do not update DNS Endpoint for External DNS if no IPs are exposed

controllers/providers/dns/infoblox.go

@@ -70,7 +70,11 @@ func (p *InfobloxProvider) CreateZoneDelegationForExternalDNS(gslb *k8gbv1beta1.
 
 	var addresses []string
 	if p.config.CoreDNSExposed {
-		addresses, err = p.assistant.CoreDNSExposedIPs()
+		if p.config.CoreDNSClusterIPs {
+			addresses, err = p.assistant.CoreDNSClusterIPs()
+		} else {
+			addresses, err = p.assistant.CoreDNSExposedIPs()
+		}
 	} else {
 		addresses = gslb.Status.LoadBalancer.ExposedIPs
 	}