Add PVC volume expansion

config/rbac/role.yaml

@@ -44,6 +44,8 @@ rules:
   - delete
   - get
   - list
+  - patch
+  - update
   - watch
 - apiGroups:
   - ""

controllers/solr_cluster_ops_util.go

@@ -27,6 +27,7 @@ import (
 	"github.com/go-logr/logr"
 	appsv1 "k8s.io/api/apps/v1"
 	corev1 "k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/api/resource"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/utils/pointer"
 	"net/url"
@@ -53,6 +54,7 @@ const (
 	ScaleUpLock         SolrClusterOperationType = "ScalingUp"
 	UpdateLock          SolrClusterOperationType = "RollingUpdate"
 	BalanceReplicasLock SolrClusterOperationType = "BalanceReplicas"
+	PvcExpansionLock    SolrClusterOperationType = "PVCExpansion"
 )
 
 // RollingUpdateMetadata contains metadata for rolling update cluster operations.
@@ -150,6 +152,60 @@ func retryNextQueuedClusterOpWithQueue(statefulSet *appsv1.StatefulSet, clusterO
 	return hasOp, err
 }
 
+func determinePvcExpansionClusterOpLockIfNecessary(instance *solrv1beta1.SolrCloud, statefulSet *appsv1.StatefulSet) (clusterOp *SolrClusterOp, retryLaterDuration time.Duration, err error) {
+	if instance.Spec.StorageOptions.PersistentStorage != nil &&
+		instance.Spec.StorageOptions.PersistentStorage.PersistentVolumeClaimTemplate.Spec.Resources.Requests.Storage() != nil &&
+		instance.Spec.StorageOptions.PersistentStorage.PersistentVolumeClaimTemplate.Spec.Resources.Requests.Storage().String() != statefulSet.Annotations[util.StorageMinimumSizeAnnotation] {
+		// First make sure that the new Storage request is greater than what already is set.
+		// PVCs cannot be shrunk
+		newSize := instance.Spec.StorageOptions.PersistentStorage.PersistentVolumeClaimTemplate.Spec.Resources.Requests.Storage()
+		// If there is no old size to update, the StatefulSet can be just set to use the new PVC size without any issue.
+		// Only do a cluster operation if we are expanding from an existing size to a new size
+		if oldSizeStr, hasOldSize := statefulSet.Annotations[util.StorageMinimumSizeAnnotation]; hasOldSize {
+			if oldSize, e := resource.ParseQuantity(oldSizeStr); e != nil {
+				err = e
+				// TODO: add an event
+			} else {
+				// Only update to the new size if it is bigger, we cannot shrink PVCs
+				if newSize.Cmp(oldSize) > 0 {
+					clusterOp = &SolrClusterOp{
+						Operation: PvcExpansionLock,
+						Metadata:  newSize.String(),
+					}
+				}
+				// TODO: add an event saying that we cannot shrink PVCs
+			}
+		}
+	}
+	return
+}
+
+// handleManagedCloudScaleUp does the logic of a managed and "locked" cloud scale up operation.
+// This will likely take many reconcile loops to complete, as it is moving replicas to the pods that have recently been scaled up.
+func handlePvcExpansion(ctx context.Context, r *SolrCloudReconciler, instance *solrv1beta1.SolrCloud, statefulSet *appsv1.StatefulSet, clusterOp *SolrClusterOp, logger logr.Logger) (operationComplete bool, retryLaterDuration time.Duration, err error) {
+	var newSize resource.Quantity
+	newSize, err = resource.ParseQuantity(clusterOp.Metadata)
+	if err != nil {
+		logger.Error(err, "Could not convert PvcExpansion metadata to a resource.Quantity, as it represents the new size of PVCs", "metadata", clusterOp.Metadata)
+		return
+	}
+	operationComplete, err = r.expandPVCs(ctx, instance, statefulSet.Spec.Selector.MatchLabels, newSize, logger)
+	if err == nil && operationComplete {
+		originalStatefulSet := statefulSet.DeepCopy()
+		statefulSet.Annotations[util.StorageMinimumSizeAnnotation] = newSize.String()
+		statefulSet.Spec.Template.Annotations[util.StorageMinimumSizeAnnotation] = newSize.String()
+		if err = r.Patch(ctx, statefulSet, client.StrategicMergeFrom(originalStatefulSet)); err != nil {
+			logger.Error(err, "Error while patching StatefulSet to set the new minimum PVC size after PVCs the completion of PVC resizing", "newSize", newSize)
+			operationComplete = false
+		}
+		// Return and wait for the StatefulSet to be updated which will call the reconcile to start the rolling restart
+		retryLaterDuration = 0
+	} else if err == nil {
+		retryLaterDuration = time.Second * 5
+	}
+	return
+}
+
 func determineScaleClusterOpLockIfNecessary(ctx context.Context, r *SolrCloudReconciler, instance *solrv1beta1.SolrCloud, statefulSet *appsv1.StatefulSet, scaleDownOpIsQueued bool, podList []corev1.Pod, blockReconciliationOfStatefulSet bool, logger logr.Logger) (clusterOp *SolrClusterOp, retryLaterDuration time.Duration, err error) {
 	desiredPods := int(*instance.Spec.Replicas)
 	configuredPods := int(*statefulSet.Spec.Replicas)
@@ -291,7 +347,8 @@ func cleanupManagedCloudScaleDown(ctx context.Context, r *SolrCloudReconciler, p
 // handleManagedCloudScaleUp does the logic of a managed and "locked" cloud scale up operation.
 // This will likely take many reconcile loops to complete, as it is moving replicas to the pods that have recently been scaled up.
 func handleManagedCloudScaleUp(ctx context.Context, r *SolrCloudReconciler, instance *solrv1beta1.SolrCloud, statefulSet *appsv1.StatefulSet, clusterOp *SolrClusterOp, podList []corev1.Pod, logger logr.Logger) (operationComplete bool, nextClusterOperation *SolrClusterOp, err error) {
-	desiredPods, err := strconv.Atoi(clusterOp.Metadata)
+	desiredPods := 0
+	desiredPods, err = strconv.Atoi(clusterOp.Metadata)
 	if err != nil {
 		logger.Error(err, "Could not convert ScaleUp metadata to int, as it represents the number of nodes to scale to", "metadata", clusterOp.Metadata)
 		return

controllers/solrcloud_controller.go

@@ -22,6 +22,7 @@ import (
 	"crypto/md5"
 	"fmt"
 	policyv1 "k8s.io/api/policy/v1"
+	"k8s.io/apimachinery/pkg/api/resource"
 	"k8s.io/apimachinery/pkg/runtime"
 	"reflect"
 	"sort"
@@ -72,7 +73,7 @@ func UseZkCRD(useCRD bool) {
 //+kubebuilder:rbac:groups=networking.k8s.io,resources=ingresses/status,verbs=get
 //+kubebuilder:rbac:groups="",resources=configmaps,verbs=get;list;watch;create;update;patch;delete
 //+kubebuilder:rbac:groups="",resources=configmaps/status,verbs=get
-//+kubebuilder:rbac:groups="",resources=persistentvolumeclaims,verbs=get;list;watch;delete
+//+kubebuilder:rbac:groups="",resources=persistentvolumeclaims,verbs=get;list;watch;update;patch;delete
 //+kubebuilder:rbac:groups=policy,resources=poddisruptionbudgets,verbs=get;list;watch;create;update;patch;delete
 //+kubebuilder:rbac:groups=zookeeper.pravega.io,resources=zookeeperclusters,verbs=get;list;watch;create;update;patch;delete
 //+kubebuilder:rbac:groups=zookeeper.pravega.io,resources=zookeeperclusters/status,verbs=get
@@ -483,6 +484,8 @@ func (r *SolrCloudReconciler) Reconcile(ctx context.Context, req ctrl.Request) (
 			operationComplete, nextClusterOperation, err = handleManagedCloudScaleUp(ctx, r, instance, statefulSet, clusterOp, podList, logger)
 		case BalanceReplicasLock:
 			operationComplete, requestInProgress, retryLaterDuration, err = util.BalanceReplicasForCluster(ctx, instance, statefulSet, clusterOp.Metadata, clusterOp.Metadata, logger)
+		case PvcExpansionLock:
+			operationComplete, retryLaterDuration, err = handlePvcExpansion(ctx, r, instance, statefulSet, clusterOp, logger)
 		default:
 			operationFound = false
 			// This shouldn't happen, but we don't want to be stuck if it does.
@@ -550,6 +553,12 @@ func (r *SolrCloudReconciler) Reconcile(ctx context.Context, req ctrl.Request) (
 				clusterOpQueue[queueIdx] = *clusterOp
 				clusterOp = nil
 			}
+			clusterOp, retryLaterDuration, err = determinePvcExpansionClusterOpLockIfNecessary(instance, statefulSet)
+			// If the new clusterOperation is an update to a queued clusterOp, just change the operation that is already queued
+			if queueIdx, opIsQueued := queuedRetryOps[UpdateLock]; clusterOp != nil && opIsQueued {
+				clusterOpQueue[queueIdx] = *clusterOp
+				clusterOp = nil
+			}
 
 			// If a non-managed scale needs to take place, this method will update the StatefulSet without starting
 			// a "locked" cluster operation
@@ -932,6 +941,46 @@ func (r *SolrCloudReconciler) reconcileZk(ctx context.Context, logger logr.Logge
 	return nil
 }
 
+func (r *SolrCloudReconciler) expandPVCs(ctx context.Context, cloud *solrv1beta1.SolrCloud, pvcLabelSelector map[string]string, newSize resource.Quantity, logger logr.Logger) (expansionComplete bool, err error) {
+	var pvcList corev1.PersistentVolumeClaimList
+	pvcList, err = r.getPVCList(ctx, cloud, pvcLabelSelector)
+	if err != nil {
+		return
+	}
+	expansionCompleteCount := 0
+	for _, pvcItem := range pvcList.Items {
+		if pvcExpansionComplete, e := r.expandPVC(ctx, &pvcItem, newSize, logger); e != nil {
+			err = e
+		} else if pvcExpansionComplete {
+			expansionCompleteCount += 1
+		}
+	}
+	// If all PVCs have been expanded, then we are done
+	expansionComplete = err == nil && expansionCompleteCount == len(pvcList.Items)
+	return
+}
+
+func (r *SolrCloudReconciler) expandPVC(ctx context.Context, pvc *corev1.PersistentVolumeClaim, newSize resource.Quantity, logger logr.Logger) (expansionComplete bool, err error) {
+	// If the current capacity is >= the new size, then there is nothing to do, expansion is complete
+	if pvc.Status.Capacity.Storage().Cmp(newSize) >= 0 {
+		// TODO: Eventually use the pvc.Status.AllocatedResources and pvc.Status.AllocatedResourceStatuses to determine the status of PVC Expansion and react to failures
+		expansionComplete = true
+	} else if !pvc.Spec.Resources.Requests.Storage().Equal(newSize) {
+		// Update the pvc if the capacity request is different.
+		// The newSize might be smaller than the current size, but this is supported as the last size might have been too
+		// big for the storage quota, so it was lowered.
+		// As long as the PVCs current capacity is lower than the new size, we are still good to update the PVC.
+		originalPvc := pvc.DeepCopy()
+		pvc.Spec.Resources.Requests[corev1.ResourceStorage] = newSize
+		if err = r.Patch(ctx, pvc, client.StrategicMergeFrom(originalPvc)); err != nil {
+			logger.Error(err, "Error while expanding PersistentVolumeClaim size", "persistentVolumeClaim", pvc.Name, "size", newSize)
+		} else {
+			logger.Info("Expanded PersistentVolumeClaim size", "persistentVolumeClaim", pvc.Name, "size", newSize)
+		}
+	}
+	return
+}
+
 // Logic derived from:
 // - https://book.kubebuilder.io/reference/using-finalizers.html
 // - https://github.com/pravega/zookeeper-operator/blob/v0.2.9/pkg/controller/zookeepercluster/zookeepercluster_controller.go#L629
@@ -978,16 +1027,15 @@ func (r *SolrCloudReconciler) reconcileStorageFinalizer(ctx context.Context, clo
 	return nil
 }
 
-func (r *SolrCloudReconciler) getPVCCount(ctx context.Context, cloud *solrv1beta1.SolrCloud, pvcLabelSelector map[string]string) (pvcCount int, err error) {
+func (r *SolrCloudReconciler) getPVCCount(ctx context.Context, cloud *solrv1beta1.SolrCloud, pvcLabelSelector map[string]string) (int, error) {
 	pvcList, err := r.getPVCList(ctx, cloud, pvcLabelSelector)
 	if err != nil {
 		return -1, err
 	}
-	pvcCount = len(pvcList.Items)
-	return pvcCount, nil
+	return len(pvcList.Items), nil
 }
 
-func (r *SolrCloudReconciler) cleanupOrphanPVCs(ctx context.Context, cloud *solrv1beta1.SolrCloud, statefulSet *appsv1.StatefulSet, pvcLabelSelector map[string]string, logger logr.Logger) (err error) {
+func (r *SolrCloudReconciler) cleanupOrphanPVCs(ctx context.Context, cloud *solrv1beta1.SolrCloud, statefulSet *appsv1.StatefulSet, pvcLabelSelector map[string]string, logger logr.Logger) error {
 	// this check should make sure we do not delete the PVCs before the STS has scaled down
 	if cloud.Status.ReadyReplicas == cloud.Status.Replicas {
 		pvcList, err := r.getPVCList(ctx, cloud, pvcLabelSelector)
@@ -1007,32 +1055,33 @@ func (r *SolrCloudReconciler) cleanupOrphanPVCs(ctx context.Context, cloud *solr
 				}
 			}
 		}
+		return err
 	}
 	return nil
 }
 
-func (r *SolrCloudReconciler) getPVCList(ctx context.Context, cloud *solrv1beta1.SolrCloud, pvcLabelSelector map[string]string) (pvList corev1.PersistentVolumeClaimList, err error) {
+func (r *SolrCloudReconciler) getPVCList(ctx context.Context, cloud *solrv1beta1.SolrCloud, pvcLabelSelector map[string]string) (corev1.PersistentVolumeClaimList, error) {
 	selector, err := metav1.LabelSelectorAsSelector(&metav1.LabelSelector{
 		MatchLabels: pvcLabelSelector,
 	})
-	pvclistOps := &client.ListOptions{
+	pvcListOps := &client.ListOptions{
 		Namespace:     cloud.Namespace,
 		LabelSelector: selector,
 	}
 	pvcList := &corev1.PersistentVolumeClaimList{}
-	err = r.Client.List(ctx, pvcList, pvclistOps)
+	err = r.Client.List(ctx, pvcList, pvcListOps)
 	return *pvcList, err
 }
 
-func (r *SolrCloudReconciler) cleanUpAllPVCs(ctx context.Context, cloud *solrv1beta1.SolrCloud, pvcLabelSelector map[string]string, logger logr.Logger) (err error) {
+func (r *SolrCloudReconciler) cleanUpAllPVCs(ctx context.Context, cloud *solrv1beta1.SolrCloud, pvcLabelSelector map[string]string, logger logr.Logger) error {
 	pvcList, err := r.getPVCList(ctx, cloud, pvcLabelSelector)
 	if err != nil {
 		return err
 	}
 	for _, pvcItem := range pvcList.Items {
 		r.deletePVC(ctx, pvcItem, logger)
 	}
-	return nil
+	return err
 }
 
 func (r *SolrCloudReconciler) deletePVC(ctx context.Context, pvcItem corev1.PersistentVolumeClaim, logger logr.Logger) {

controllers/util/solr_util.go

@@ -57,6 +57,7 @@ const (
 	// These are to be saved on a statefulSet update
 	ClusterOpsLockAnnotation       = "solr.apache.org/clusterOpsLock"
 	ClusterOpsRetryQueueAnnotation = "solr.apache.org/clusterOpsRetryQueue"
+	StorageMinimumSizeAnnotation   = "solr.apache.org/storageMinimumSize"
 
 	SolrIsNotStoppedReadinessCondition       = "solr.apache.org/isNotStopped"
 	SolrReplicasNotEvictedReadinessCondition = "solr.apache.org/replicasNotEvicted"
@@ -200,6 +201,13 @@ func GenerateStatefulSet(solrCloud *solr.SolrCloud, solrCloudStatus *solr.SolrCl
 				Spec: pvc.Spec,
 			},
 		}
+		if pvc.Spec.Resources.Requests.Storage() != nil {
+			annotations[StorageMinimumSizeAnnotation] = pvc.Spec.Resources.Requests.Storage().String()
+			if podAnnotations == nil {
+				podAnnotations = make(map[string]string, 1)
+			}
+			podAnnotations[StorageMinimumSizeAnnotation] = pvc.Spec.Resources.Requests.Storage().String()
+		}
 	} else {
 		ephemeralVolume := corev1.Volume{
 			Name:         solrDataVolumeName,
@@ -680,6 +688,22 @@ func MaintainPreservedStatefulSetFields(expected, found *appsv1.StatefulSet) {
 			}
 			expected.Annotations[ClusterOpsRetryQueueAnnotation] = queue
 		}
+		if storage, hasStorage := found.Annotations[StorageMinimumSizeAnnotation]; hasStorage {
+			if expected.Annotations == nil {
+				expected.Annotations = make(map[string]string, 1)
+			}
+			expected.Annotations[StorageMinimumSizeAnnotation] = storage
+		}
+	}
+	if found.Spec.Template.Annotations != nil {
+		// Note: the Pod template storage annotation is used to start a rolling restart,
+		// it should always match the StatefulSet's storage annotation
+		if storage, hasStorage := found.Spec.Template.Annotations[StorageMinimumSizeAnnotation]; hasStorage {
+			if expected.Spec.Template.Annotations == nil {
+				expected.Spec.Template.Annotations = make(map[string]string, 1)
+			}
+			expected.Spec.Template.Annotations[StorageMinimumSizeAnnotation] = storage
+		}
 	}
 
 	// Scaling (i.e. changing) the number of replicas in the SolrCloud statefulSet is handled during the clusterOps

docs/solr-cloud/solr-cloud-crd.md

@@ -61,8 +61,9 @@ These options can be found in `SolrCloud.spec.dataStorage`
   - **`pvcTemplate`** - The template of the PVC to use for the solr data PVCs. By default the name will be "data".
     Only the `pvcTemplate.spec` field is required, metadata is optional.
 
-    Note: This template cannot be changed unless the SolrCloud is deleted and recreated.
-    This is a [limitation of StatefulSets and PVCs in Kubernetes](https://github.com/kubernetes/enhancements/issues/661).
+    Note: Currently, [Kubernetes does not support PVC resizing (expanding) in StatefulSets](https://github.com/kubernetes/enhancements/issues/661).
+    However, The Solr Operator will manage the PVC expansion for users until this is supported by default in Kubernetes.
+    Therefore the `pvcTemplate.spec` can have an update to `pvcTemplate.spec.resources.requests`, but all other fields should be considered immutable.
 - **`ephemeral`**
 
   There are two types of ephemeral volumes that can be specified.

docs/upgrade-notes.md

@@ -124,7 +124,7 @@ _Note that the Helm chart version does not contain a `v` prefix, which the downl
 ### v0.8.0
 - **The minimum supported Solr version is now 8.11**
   If you are unable to use a newer version of Solr, please install the `v0.7.1` version of the Solr Operator.
-  However, it is strongly suggested to upgrade to newer versions of Solr that are actively supported.q
+  However, it is strongly suggested to upgrade to newer versions of Solr that are actively supported.
   See the [version compatibility matrix](#solr-versions) for more information.
 
 - **Kubernetes support is now limited to 1.22+.**  

helm/solr-operator/templates/role.yaml

@@ -48,6 +48,8 @@ rules:
   - delete
   - get
   - list
+  - patch
+  - update
   - watch
 - apiGroups:
   - ""

helm/solr/Chart.yaml

@@ -42,15 +42,12 @@ annotations:
   # Allowed syntax is described at: https://artifacthub.io/docs/topics/annotations/helm/#example
   artifacthub.io/changes: |
     - kind: added
-      description: Addition 1
+      description: Allow resizing (expanding) of persistent data PVCs
       links:
         - name: Github Issue
-          url: https://github.com/issue-url
-    - kind: changed
-      description: Change 2
-      links:
+          url: https://github.com/apache/solr-operator/issues/709
         - name: Github PR
-          url: https://github.com/pr-url
+          url: https://github.com/apache/solr-operator/pull/712
   artifacthub.io/containsSecurityUpdates: "false"
   artifacthub.io/recommendations: |
     - url: https://artifacthub.io/packages/helm/apache-solr/solr-operator