Create replica-1 sc for external mode if topology details are provided

controllers/storagecluster/external_resources.go

@@ -30,6 +30,7 @@ const (
 	cephFsStorageClassName                = "cephfs"
 	cephRbdStorageClassName               = "ceph-rbd"
 	cephRbdRadosNamespaceStorageClassName = "ceph-rbd-rados-namespace"
+	cephRbdTopologyStorageClassName       = "ceph-rbd-topology"
 	cephRgwStorageClassName               = "ceph-rgw"
 	externalCephRgwEndpointKey            = "endpoint"
 	cephRgwTLSSecretKey                   = "ceph-rgw-tls-cert"
@@ -371,6 +372,7 @@ func (r *StorageClusterReconciler) createExternalStorageClusterResources(instanc
 
 		case "StorageClass":
 			var scc StorageClassConfiguration
+			var err error
 			if d.Name == cephFsStorageClassName {
 				scc = newCephFilesystemStorageClassConfiguration(instance)
 				enableRookCSICephFS = true
@@ -380,6 +382,13 @@ func (r *StorageClusterReconciler) createExternalStorageClusterResources(instanc
 				scc = newCephBlockPoolStorageClassConfiguration(instance)
 				// update the storageclass name to rados storagesclass name
 				scc.storageClass.Name = fmt.Sprintf("%s-%s", instance.Name, d.Name)
+			} else if d.Name == cephRbdTopologyStorageClassName {
+				scc = newNonResilientCephBlockPoolStorageClassConfiguration(instance)
+				scc.storageClass.Parameters["topologyConstrainedPools"], err = getTopologyConstrainedPoolsExternalMode(d.Data)
+				if err != nil {
+					r.Log.Error(err, "Failed to get topologyConstrainedPools from external mode secret.", "StorageClass", klog.KRef(instance.Namespace, d.Name))
+					return err
+				}
 			} else if d.Name == cephRgwStorageClassName {
 				rgwEndpoint := d.Data[externalCephRgwEndpointKey]
 				if err := checkEndpointReachable(rgwEndpoint, 5*time.Second); err != nil {

controllers/storagecluster/storageclasses.go

@@ -528,3 +528,44 @@ func getTopologyConstrainedPools(initData *ocsv1.StorageCluster) string {
 	}
 	return string(topologyConstrainedPoolsStr)
 }
+
+// getTopologyConstrainedPoolsExternalMode constructs the topologyConstrainedPools string for external mode from the data map
+func getTopologyConstrainedPoolsExternalMode(data map[string]string) (string, error) {
+	type topologySegment struct {
+		DomainLabel string `json:"domainLabel"`
+		DomainValue string `json:"value"`
+	}
+	// TopologyConstrainedPool stores the pool name and a list of its associated topology domain values.
+	type topologyConstrainedPool struct {
+		PoolName       string            `json:"poolName"`
+		DomainSegments []topologySegment `json:"domainSegments"`
+	}
+	var topologyConstrainedPools []topologyConstrainedPool
+
+	domainLabel := data["topologyFailureDomainLabel"]
+	domainValues := strings.Split(data["topologyFailureDomainValues"], ",")
+	poolNames := strings.Split(data["topologyPools"], ",")
+
+	// Check if the number of pool names and domain values are equal
+	if len(poolNames) != len(domainValues) {
+		return "", fmt.Errorf("number of pool names and domain values are not equal")
+	}
+
+	for i, poolName := range poolNames {
+		topologyConstrainedPools = append(topologyConstrainedPools, topologyConstrainedPool{
+			PoolName: poolName,
+			DomainSegments: []topologySegment{
+				{
+					DomainLabel: domainLabel,
+					DomainValue: domainValues[i],
+				},
+			},
+		})
+	}
+	// returning as string as parameters are of type map[string]string
+	topologyConstrainedPoolsStr, err := json.MarshalIndent(topologyConstrainedPools, "", "  ")
+	if err != nil {
+		return "", err
+	}
+	return string(topologyConstrainedPoolsStr), nil
+}