Fix scaling when using ingress-addressed nodes

api/v1beta1/solrcloud_types.go

@@ -1227,6 +1227,13 @@ func (sc *SolrCloud) GetAllSolrPodNames() []string {
 	if sc.Spec.Replicas != nil {
 		replicas = int(*sc.Spec.Replicas)
 	}
+	if int(sc.Status.Replicas) > replicas {
+		replicas = int(sc.Status.Replicas)
+	}
+	return sc.GetSolrPodNames(replicas)
+}
+
+func (sc *SolrCloud) GetSolrPodNames(replicas int) []string {
 	podNames := make([]string, replicas)
 	statefulSetName := sc.StatefulSetName()
 	for i := range podNames {

controllers/solr_cluster_ops_util.go

@@ -151,7 +151,7 @@ func retryNextQueuedClusterOpWithQueue(statefulSet *appsv1.StatefulSet, clusterO
 	return hasOp, err
 }
 
-func determineScaleClusterOpLockIfNecessary(ctx context.Context, r *SolrCloudReconciler, instance *solrv1beta1.SolrCloud, statefulSet *appsv1.StatefulSet, scaleDownOpIsQueued bool, podList []corev1.Pod, logger logr.Logger) (clusterOp *SolrClusterOp, retryLaterDuration time.Duration, err error) {
+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)
 	if desiredPods != configuredPods {
@@ -170,11 +170,26 @@ func determineScaleClusterOpLockIfNecessary(ctx context.Context, r *SolrCloudRec
 				Metadata:  strconv.Itoa(configuredPods - 1),
 			}
 		} else if desiredPods > configuredPods && (instance.Spec.Scaling.PopulatePodsOnScaleUp == nil || *instance.Spec.Scaling.PopulatePodsOnScaleUp) {
+			// We need to wait for all pods to become healthy to scale up in a managed fashion, otherwise
+			// the balancing will skip some pods
 			if len(podList) < configuredPods {
 				// There are not enough pods, the statefulSet controller has yet to create the previously desired pods.
 				// Do not start the scale up until these missing pods are created.
 				return nil, time.Second * 5, nil
 			}
+			// If Solr nodes are advertised by their individual node services (through an ingress)
+			// then make sure that the host aliases are set for all desired pods before starting a scale-up.
+			// If the host aliases do not already include the soon-to-be created pods, then Solr might not be able to balance
+			// replicas onto the new hosts.
+			// We need to make sure that the StatefulSet is updated with these new hostAliases before the scale up occurs.
+			if instance.UsesIndividualNodeServices() && instance.Spec.SolrAddressability.External.UseExternalAddress {
+				for _, pod := range podList {
+					if len(pod.Spec.HostAliases) < desiredPods {
+						return nil, time.Second * 5, nil
+					}
+				}
+			}
+
 			clusterOp = &SolrClusterOp{
 				Operation: ScaleUpLock,
 				Metadata:  strconv.Itoa(desiredPods),
@@ -349,7 +364,8 @@ func handleManagedCloudRollingUpdate(ctx context.Context, r *SolrCloudReconciler
 		}
 		operationComplete = true
 		// Only do a re-balancing for rolling restarts that migrated replicas
-		if updateMetadata.RequiresReplicaMigration {
+		// If a scale-up will occur afterwards, skip the re-balancing, because it will occur after the scale-up anyway
+		if updateMetadata.RequiresReplicaMigration && *instance.Spec.Replicas <= *statefulSet.Spec.Replicas {
 			nextClusterOp = &SolrClusterOp{
 				Operation: BalanceReplicasLock,
 				Metadata:  "RollingUpdateComplete",
@@ -371,7 +387,7 @@ func handleManagedCloudRollingUpdate(ctx context.Context, r *SolrCloudReconciler
 		// We won't kill pods that we need the cluster state for, but we can kill the pods that are already not running.
 		// This is important for scenarios where there is a bad pod config and nothing is running, but we need to do
 		// a restart to get a working pod config.
-		state, retryLater, apiError := util.GetNodeReplicaState(ctx, instance, hasReadyPod, logger)
+		state, retryLater, apiError := util.GetNodeReplicaState(ctx, instance, statefulSet, hasReadyPod, logger)
 		if apiError != nil {
 			return false, true, 0, nil, apiError
 		} else if !retryLater {

controllers/solrcloud_controller.go

@@ -152,6 +152,11 @@ func (r *SolrCloudReconciler) Reconcile(ctx context.Context, req ctrl.Request) (
 	hostNameIpMap := make(map[string]string)
 	// Generate a service for every Node
 	if instance.UsesIndividualNodeServices() {
+		// When updating the statefulSet below, the hostNameIpMap is just used to add new IPs or modify existing ones.
+		// When scaling down, the hostAliases that are no longer found here will not be removed from the hostAliases in the statefulSet pod spec.
+		// Therefore, it should be ok that we are not reconciling the node services that will be scaled down in the future.
+		// This is unfortunately the reality since we don't have the statefulSet yet to determine how many Solr pods are still running,
+		// we just have Spec.replicas which is the requested pod count.
 		for _, nodeName := range solrNodeNames {
 			err, ip := r.reconcileNodeService(ctx, logger, instance, nodeName)
 			if err != nil {
@@ -161,6 +166,7 @@ func (r *SolrCloudReconciler) Reconcile(ctx context.Context, req ctrl.Request) (
 			if instance.Spec.SolrAddressability.External.UseExternalAddress {
 				if ip == "" {
 					// If we are using this IP in the hostAliases of the statefulSet, it needs to be set for every service before trying to update the statefulSet
+					// TODO: Make an event here
 					blockReconciliationOfStatefulSet = true
 				} else {
 					hostNameIpMap[instance.AdvertisedNodeHost(nodeName)] = ip
@@ -319,36 +325,6 @@ func (r *SolrCloudReconciler) Reconcile(ctx context.Context, req ctrl.Request) (
 		}
 	}
 
-	extAddressabilityOpts := instance.Spec.SolrAddressability.External
-	if extAddressabilityOpts != nil && extAddressabilityOpts.Method == solrv1beta1.Ingress {
-		// Generate Ingress
-		ingress := util.GenerateIngress(instance, solrNodeNames)
-
-		// Check if the Ingress already exists
-		ingressLogger := logger.WithValues("ingress", ingress.Name)
-		foundIngress := &netv1.Ingress{}
-		err = r.Get(ctx, types.NamespacedName{Name: ingress.Name, Namespace: ingress.Namespace}, foundIngress)
-		if err != nil && errors.IsNotFound(err) {
-			ingressLogger.Info("Creating Ingress")
-			if err = controllerutil.SetControllerReference(instance, ingress, r.Scheme); err == nil {
-				err = r.Create(ctx, ingress)
-			}
-		} else if err == nil {
-			var needsUpdate bool
-			needsUpdate, err = util.OvertakeControllerRef(instance, foundIngress, r.Scheme)
-			needsUpdate = util.CopyIngressFields(ingress, foundIngress, ingressLogger) || needsUpdate
-
-			// Update the found Ingress and write the result back if there are any changes
-			if needsUpdate && err == nil {
-				ingressLogger.Info("Updating Ingress")
-				err = r.Update(ctx, foundIngress)
-			}
-		}
-		if err != nil {
-			return requeueOrNot, err
-		}
-	}
-
 	var statefulSet *appsv1.StatefulSet
 
 	if !blockReconciliationOfStatefulSet {
@@ -416,6 +392,39 @@ func (r *SolrCloudReconciler) Reconcile(ctx context.Context, req ctrl.Request) (
 	if err != nil {
 		return requeueOrNot, err
 	}
+	if statefulSet != nil && statefulSet.Spec.Replicas != nil {
+		solrNodeNames = instance.GetSolrPodNames(int(*statefulSet.Spec.Replicas))
+	}
+
+	extAddressabilityOpts := instance.Spec.SolrAddressability.External
+	if extAddressabilityOpts != nil && extAddressabilityOpts.Method == solrv1beta1.Ingress {
+		// Generate Ingress
+		ingress := util.GenerateIngress(instance, solrNodeNames)
+
+		// Check if the Ingress already exists
+		ingressLogger := logger.WithValues("ingress", ingress.Name)
+		foundIngress := &netv1.Ingress{}
+		err = r.Get(ctx, types.NamespacedName{Name: ingress.Name, Namespace: ingress.Namespace}, foundIngress)
+		if err != nil && errors.IsNotFound(err) {
+			ingressLogger.Info("Creating Ingress")
+			if err = controllerutil.SetControllerReference(instance, ingress, r.Scheme); err == nil {
+				err = r.Create(ctx, ingress)
+			}
+		} else if err == nil {
+			var needsUpdate bool
+			needsUpdate, err = util.OvertakeControllerRef(instance, foundIngress, r.Scheme)
+			needsUpdate = util.CopyIngressFields(ingress, foundIngress, ingressLogger) || needsUpdate
+
+			// Update the found Ingress and write the result back if there are any changes
+			if needsUpdate && err == nil {
+				ingressLogger.Info("Updating Ingress")
+				err = r.Update(ctx, foundIngress)
+			}
+		}
+		if err != nil {
+			return requeueOrNot, err
+		}
+	}
 
 	// *********************************************************
 	// The operations after this require a statefulSet to exist,
@@ -546,7 +555,7 @@ func (r *SolrCloudReconciler) Reconcile(ctx context.Context, req ctrl.Request) (
 			// a "locked" cluster operation
 			if clusterOp == nil {
 				_, scaleDownOpIsQueued := queuedRetryOps[ScaleDownLock]
-				clusterOp, retryLaterDuration, err = determineScaleClusterOpLockIfNecessary(ctx, r, instance, statefulSet, scaleDownOpIsQueued, podList, logger)
+				clusterOp, retryLaterDuration, err = determineScaleClusterOpLockIfNecessary(ctx, r, instance, statefulSet, scaleDownOpIsQueued, podList, blockReconciliationOfStatefulSet, logger)
 
 				// If the new clusterOperation is an update to a queued clusterOp, just change the operation that is already queued
 				if clusterOp != nil {

controllers/util/common.go

@@ -432,7 +432,29 @@ func CopyPodTemplates(from, to *corev1.PodTemplateSpec, basePath string, logger
 
 	if !DeepEqualWithNils(to.Spec.HostAliases, from.Spec.HostAliases) {
 		requireUpdate = true
-		to.Spec.HostAliases = from.Spec.HostAliases
+		if to.Spec.HostAliases == nil {
+			to.Spec.HostAliases = from.Spec.HostAliases
+		} else {
+			// Do not remove aliases that are no longer used.
+			// This is in case Solr is scaling down and we want to keep the old addresses for future use.
+			for _, fromAlias := range from.Spec.HostAliases {
+				found := false
+				for i, toAlias := range to.Spec.HostAliases {
+					if fromAlias.Hostnames[0] == toAlias.Hostnames[0] {
+						found = true
+						if !DeepEqualWithNils(toAlias, fromAlias) {
+							requireUpdate = true
+							to.Spec.HostAliases[i] = fromAlias
+							break
+						}
+					}
+				}
+				if !found {
+					requireUpdate = true
+					to.Spec.HostAliases = append(to.Spec.HostAliases, fromAlias)
+				}
+			}
+		}
 		logger.Info("Update required because field changed", "field", basePath+"Spec.HostAliases", "from", to.Spec.HostAliases, "to", from.Spec.HostAliases)
 	}
 

controllers/util/solr_update_util.go

@@ -24,6 +24,7 @@ import (
 	"github.com/apache/solr-operator/controllers/util/solr_api"
 	"github.com/go-logr/logr"
 	"github.com/robfig/cron/v3"
+	appsv1 "k8s.io/api/apps/v1"
 	corev1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/util/intstr"
 	"net/url"
@@ -119,7 +120,7 @@ func (state NodeReplicaState) PodHasReplicas(cloud *solr.SolrCloud, podName stri
 	return isInClusterState && contents.replicas > 0
 }
 
-func GetNodeReplicaState(ctx context.Context, cloud *solr.SolrCloud, hasReadyPod bool, logger logr.Logger) (state NodeReplicaState, retryLater bool, err error) {
+func GetNodeReplicaState(ctx context.Context, cloud *solr.SolrCloud, statefulSet *appsv1.StatefulSet, hasReadyPod bool, logger logr.Logger) (state NodeReplicaState, retryLater bool, err error) {
 	clusterResp := &solr_api.SolrClusterStatusResponse{}
 	overseerResp := &solr_api.SolrOverseerStatusResponse{}
 
@@ -138,7 +139,7 @@ func GetNodeReplicaState(ctx context.Context, cloud *solr.SolrCloud, hasReadyPod
 			}
 		}
 		if err == nil {
-			state = findSolrNodeContents(clusterResp.ClusterStatus, overseerResp.Leader, GetAllManagedSolrNodeNames(cloud))
+			state = findSolrNodeContents(clusterResp.ClusterStatus, overseerResp.Leader, GetManagedSolrNodeNames(cloud, int(*statefulSet.Spec.Replicas)))
 		} else {
 			logger.Error(err, "Could not fetch cluster state information for cloud")
 		}
@@ -535,6 +536,15 @@ func GetAllManagedSolrNodeNames(solrCloud *solr.SolrCloud) map[string]bool {
 	return allNodeNames
 }
 
+func GetManagedSolrNodeNames(solrCloud *solr.SolrCloud, currentlyConfiguredPodCount int) map[string]bool {
+	podNames := solrCloud.GetSolrPodNames(currentlyConfiguredPodCount)
+	allNodeNames := make(map[string]bool, len(podNames))
+	for _, podName := range podNames {
+		allNodeNames[SolrNodeName(solrCloud, podName)] = true
+	}
+	return allNodeNames
+}
+
 // EvictReplicasForPodIfNecessary takes a solr Pod and migrates all replicas off of that Pod.
 // For updates this will only be called for pods using ephemeral data.
 // For scale-down operations, this can be called for pods using ephemeral or persistent data.

controllers/util/solr_util.go

@@ -556,6 +556,9 @@ func GenerateStatefulSet(solrCloud *solr.SolrCloud, solrCloudStatus *solr.SolrCl
 			VolumeClaimTemplates: pvcs,
 		},
 	}
+	if solrCloud.UsesHeadlessService() {
+		stateful.Spec.Template.Spec.Subdomain = solrCloud.HeadlessServiceName()
+	}
 
 	var imagePullSecrets []corev1.LocalObjectReference
 

helm/solr-operator/Chart.yaml

@@ -61,7 +61,6 @@ annotations:
           url: https://github.com/apache/solr-operator/issues/624
         - name: Github PR
           url: https://github.com/apache/solr-operator/pull/648
-    - kind: fixed
       description: Avoid reset of security.json if get request fails  
       links:
         - name: Github Issue
@@ -89,6 +88,13 @@ annotations:
           url: https://issues.apache.org/jira/browse/SOLR-17216
         - name: Github PR
           url: https://github.com/apache/solr-operator/pull/698
+    - kind: fixed
+      description: SolrClouds addressed via an Ingress now scale up and down safely.
+      links:
+        - name: Github Issue
+          url: https://github.com/apache/solr-operator/issues/682
+        - name: Github PR
+          url: https://github.com/apache/solr-operator/pull/692
   artifacthub.io/images: |
     - name: solr-operator
       image: apache/solr-operator:v0.9.0-prerelease

tests/e2e/solrcloud_rolling_upgrade_test.go

@@ -163,7 +163,7 @@ var _ = FDescribe("E2E - SolrCloud - Rolling Upgrades", func() {
 			}
 
 			By("waiting for the balanceReplicas to finish")
-			expectStatefulSetWithChecks(ctx, solrCloud, solrCloud.StatefulSetName(), func(g Gomega, found *appsv1.StatefulSet) {
+			expectStatefulSetWithChecksAndTimeout(ctx, solrCloud, solrCloud.StatefulSetName(), time.Second*30, time.Second, func(g Gomega, found *appsv1.StatefulSet) {
 				clusterOp, err := controllers.GetCurrentClusterOp(found)
 				g.Expect(err).ToNot(HaveOccurred(), "Error occurred while finding clusterLock for SolrCloud")
 				g.Expect(clusterOp).To(BeNil(), "StatefulSet should not have a balanceReplicas lock after balancing is complete.")