Configure target IP addresses for LVM backend

Configure the cinder-volume service's target_ip_address and
target_secondary_ip_addresses using addresses in the network attachment
status. This is necessary in order for EDPM compute nodes to be able to
make volume attachment requests (via iSCSI or NVMe/TCP) over the storage
network.

Jira: OSP-28445

controllers/cindervolume_controller.go

@@ -547,16 +547,12 @@ func (r *CinderVolumeReconciler) generateServiceConfigs(
 	labels := labels.GetLabels(instance, labels.GetGroupLabel(cinder.ServiceName), serviceLabels)
 
 	// customData hold any customization for the service.
-	customData := map[string]string{cinder.CustomServiceConfigFileName: instance.Spec.CustomServiceConfig}
+	customData := map[string]string{}
 
 	for key, data := range instance.Spec.DefaultConfigOverwrite {
 		customData[key] = data
 	}
 
-	customServiceConfig := extendCustomServiceConfig(instance.Spec.CustomServiceConfig)
-
-	customData[cinder.CustomServiceConfigFileName] = customServiceConfig
-
 	// Fetch the two service config snippets (DefaultsConfigFileName and
 	// CustomConfigFileName) from the Secret generated by the top level
 	// cinder controller, and add them to this service specific Secret.
@@ -580,14 +576,34 @@ func (r *CinderVolumeReconciler) generateServiceConfigs(
 	}
 	customData[cinder.CustomServiceConfigSecretsFileName] = customSecrets
 
+	usesLVM, customServiceConfig := processCustomServiceConfig(instance.Spec.CustomServiceConfig)
+	customData[cinder.CustomServiceConfigFileName] = customServiceConfig
+
+	templateParameters := make(map[string]interface{})
+	if usesLVM {
+		networkAttachmentAddrs := cinder.GetNetworkAttachmentAddrs(
+			instance.Namespace, instance.Spec.NetworkAttachments, instance.Status.NetworkAttachments)
+
+		// Configure target IP addresses using all addresses in the network
+		// attachments. This relies on the fact that the LVM backend can only
+		// have one replica.
+		if len(networkAttachmentAddrs) > 0 {
+			templateParameters["TargetIpAddress"] = networkAttachmentAddrs[0]
+			if len(networkAttachmentAddrs) > 1 {
+				templateParameters["TargetSecondaryIpAddresses"] = strings.Join(networkAttachmentAddrs[1:], ",")
+			}
+		}
+	}
+
 	configTemplates := []util.Template{
 		{
-			Name:         fmt.Sprintf("%s-config-data", instance.Name),
-			Namespace:    instance.Namespace,
-			Type:         util.TemplateTypeConfig,
-			InstanceType: instance.Kind,
-			CustomData:   customData,
-			Labels:       labels,
+			Name:          fmt.Sprintf("%s-config-data", instance.Name),
+			Namespace:     instance.Namespace,
+			Type:          util.TemplateTypeConfig,
+			InstanceType:  instance.Kind,
+			CustomData:    customData,
+			ConfigOptions: templateParameters,
+			Labels:        labels,
 		},
 	}
 
@@ -617,30 +633,33 @@ func (r *CinderVolumeReconciler) createHashOfInputHashes(
 	return hash, changed, nil
 }
 
-// extendCustomServiceConfig - A general purpose hook that may extend the customServiceConfig
+// processCustomServiceConfig - A general purpose hook that may extend the customServiceConfig
 // string in the CR. Note that this is not equivalent to a transforming or defaulting webhook,
 // as the CR is not updated. It only influences the final settings in cinder.conf.
 //
 // Currently this is limited to defining the list of enabled_backends in case its missing.
-func extendCustomServiceConfig(customServiceConfig string) string {
+// The function also returns a boolean that indicates whether the LVM driver is being used.
+func processCustomServiceConfig(customServiceConfig string) (bool, string) {
 	svcConfigLines := strings.Split(customServiceConfig, "\n")
 	hasEnabledBackends := false
+	usesLVM := false
+	numDrivers := 0
 	defaultSectionIdx := -1
 	sectionName := ""
 	backendNames := []string{}
 
-	for idx, line := range svcConfigLines {
-		token := strings.SplitN(strings.TrimSpace(line), "=", 2)[0]
+	for idx, rawLine := range svcConfigLines {
+		line := strings.TrimSpace(rawLine)
+		token := strings.SplitN(line, "=", 2)[0]
 
 		if token == "" || strings.HasPrefix(token, "#") {
 			// Skip blank lines and comments
 			continue
 		}
 
 		if token == "enabled_backends" {
-			// Note when the CRD already specifies the enabled_backends
+			// Note when the CR already specifies the enabled_backends
 			hasEnabledBackends = true
-			break
 
 		} else if token == "[DEFAULT]" {
 			// Note when the customServiceConfig contains a [DEFAULT] section
@@ -651,10 +670,24 @@ func extendCustomServiceConfig(customServiceConfig string) string {
 			sectionName = strings.Trim(token, "[]")
 
 		} else if token == "volume_backend_name" {
+			// The section name is used in the list of enabled_backends
 			backendNames = append(backendNames, sectionName)
+
+		} else if token == "volume_driver" {
+			numDrivers += 1
+			if strings.HasSuffix(line, ".LVMVolumeDriver") {
+				usesLVM = true
+			}
 		}
 	}
 
+	// Account for the fact that LVM is the default driver. If the backend's driver
+	// is implicitly LVM, the number of explicitly configured drivers will be less
+	// than the number of backends.
+	if numDrivers < len(backendNames) {
+		usesLVM = true
+	}
+
 	var extendedConfig string
 	if hasEnabledBackends || len(backendNames) == 0 {
 		// Nothing to do, just return the original customServiceConfig
@@ -675,5 +708,5 @@ func extendCustomServiceConfig(customServiceConfig string) string {
 		extendedConfig = strings.Join(svcConfigLines, "\n")
 	}
 
-	return extendedConfig
+	return usesLVM, extendedConfig
 }

pkg/cinder/funcs.go

@@ -13,3 +13,17 @@ func GetOwningCinderName(instance client.Object) string {
 
 	return ""
 }
+
+// GetNetworkAttachmentAddrs - Returns a list of IP addresses for all network attachments.
+func GetNetworkAttachmentAddrs(namespace string, networkAttachments []string, networkAttachmentStatus map[string][]string) []string {
+	networkAttachmentAddrs := []string{}
+
+	for _, network := range networkAttachments {
+		network_name := namespace + "/" + network
+		if network_addrs, ok := networkAttachmentStatus[network_name]; ok {
+			networkAttachmentAddrs = append(networkAttachmentAddrs, network_addrs...)
+		}
+	}
+
+	return networkAttachmentAddrs
+}

templates/cindervolume/config/01-service-defaults.conf

@@ -1,2 +1,8 @@
 [backend_defaults]
+{{ if (index . "TargetIpAddress") -}}
+target_ip_address = {{ .TargetIpAddress }}
+{{ end -}}
+{{ if (index . "TargetSecondaryIpAddresses") -}}
+target_secondary_ip_addresses = {{ .TargetSecondaryIpAddresses }}
+{{ end -}}
 use_multipath_for_image_xfer = true