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Posted to issues@solr.apache.org by "tflobbe (via GitHub)" <gi...@apache.org> on 2023/05/16 20:31:02 UTC
[GitHub] [solr-operator] tflobbe commented on a diff in pull request #561: Add managed scale-down for SolrClouds
tflobbe commented on code in PR #561:
URL: https://github.com/apache/solr-operator/pull/561#discussion_r1195591555
##########
controllers/solr_cluster_ops_util.go:
##########
@@ -0,0 +1,218 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package controllers
+
+import (
+ "context"
+ "errors"
+ solrv1beta1 "github.com/apache/solr-operator/api/v1beta1"
+ "github.com/apache/solr-operator/controllers/util"
+ "github.com/go-logr/logr"
+ appsv1 "k8s.io/api/apps/v1"
+ corev1 "k8s.io/api/core/v1"
+ "k8s.io/utils/pointer"
+ "sigs.k8s.io/controller-runtime/pkg/client"
+ "strconv"
+ "time"
+)
+
+func determineScaleClusterOpLockIfNecessary(ctx context.Context, r *SolrCloudReconciler, instance *solrv1beta1.SolrCloud, statefulSet *appsv1.StatefulSet, podList []corev1.Pod, logger logr.Logger) (clusterOpLock string, clusterOpMetadata string, retryLaterDuration time.Duration, err error) {
+ desiredPods := int(*instance.Spec.Replicas)
+ configuredPods := int(*statefulSet.Spec.Replicas)
+ if desiredPods != configuredPods {
+ scaleTo := -1
+ // Start a scaling operation
+ if desiredPods < configuredPods {
+ // Scale down!
+ // The option is enabled by default, so treat "nil" like "true"
+ if instance.Spec.Autoscaling.VacatePodsOnScaleDown == nil || *instance.Spec.Autoscaling.VacatePodsOnScaleDown {
+ if desiredPods > 0 {
+ // We only support one scaling down one pod at-a-time if not scaling down to 0 pods
+ scaleTo = configuredPods - 1
+ } else {
+ scaleTo = 0
+ }
+ } else {
+ // The cloud is not setup to use managed scale-down
+ err = scaleCloudUnmanaged(ctx, r, statefulSet, desiredPods, logger)
+ }
+ } else if desiredPods > configuredPods {
+ // Scale up!
+ // TODO: replicasScaleUp is not supported, so do not make a clusterOp out of it, just do the patch
+ err = scaleCloudUnmanaged(ctx, r, statefulSet, desiredPods, logger)
+ }
+ if scaleTo > -1 {
+ clusterOpLock = util.ScaleLock
+ clusterOpMetadata = strconv.Itoa(scaleTo)
+ }
+ }
+ return
+}
+
+func handleLockedClusterOpScale(ctx context.Context, r *SolrCloudReconciler, instance *solrv1beta1.SolrCloud, statefulSet *appsv1.StatefulSet, podList []corev1.Pod, logger logr.Logger) (retryLaterDuration time.Duration, err error) {
+ if scalingToNodes, hasAnn := statefulSet.Annotations[util.ClusterOpsMetadataAnnotation]; hasAnn {
+ if scalingToNodesInt, convErr := strconv.Atoi(scalingToNodes); convErr != nil {
+ logger.Error(convErr, "Could not convert statefulSet annotation to int for scale-down-to information", "annotation", util.ClusterOpsMetadataAnnotation, "value", scalingToNodes)
+ err = convErr
+ } else {
+ replicaManagementComplete := false
+ if scalingToNodesInt < int(*statefulSet.Spec.Replicas) {
+ // Manage scaling down the SolrCloud
+ replicaManagementComplete, err = handleManagedCloudScaleDown(ctx, r, instance, statefulSet, scalingToNodesInt, podList, logger)
+ // } else if scalingToNodesInt > int(*statefulSet.Spec.Replicas) {
+ // TODO: Utilize the scaled-up nodes in the future, however Solr does not currently have APIs for this.
+ // TODO: Think about the order of scale-up and restart when individual nodeService IPs are injected into the pods.
+ // TODO: Will likely want to do a scale-up of the service first, then do the rolling restart of the cluster, then utilize the node.
+ } else {
+ // This shouldn't happen. The ScalingToNodesAnnotation is removed when the statefulSet size changes, through a Patch.
+ // But if it does happen, we should just remove the annotation and move forward.
+ patchedStatefulSet := statefulSet.DeepCopy()
+ delete(patchedStatefulSet.Annotations, util.ClusterOpsLockAnnotation)
+ delete(patchedStatefulSet.Annotations, util.ClusterOpsMetadataAnnotation)
+ if err = r.Patch(ctx, patchedStatefulSet, client.StrategicMergeFrom(statefulSet)); err != nil {
+ logger.Error(err, "Error while patching StatefulSet to remove unneeded clusterLockOp annotation for scaling to the current amount of nodes")
+ } else {
+ statefulSet = patchedStatefulSet
+ }
+ }
+
+ // Scale down the statefulSet to represent the new number of utilizedPods, if it is lower than the current number of pods
+ // Also remove the "scalingToNodes" annotation, as that acts as a lock on the cluster, so that other operations,
+ // such as scale-up, pod updates and further scale-down cannot happen at the same time.
+ if replicaManagementComplete {
+ patchedStatefulSet := statefulSet.DeepCopy()
+ patchedStatefulSet.Spec.Replicas = pointer.Int32(int32(scalingToNodesInt))
+ delete(patchedStatefulSet.Annotations, util.ClusterOpsLockAnnotation)
+ delete(patchedStatefulSet.Annotations, util.ClusterOpsMetadataAnnotation)
+ if err = r.Patch(ctx, patchedStatefulSet, client.StrategicMergeFrom(statefulSet)); err != nil {
+ logger.Error(err, "Error while patching StatefulSet to scale down SolrCloud", "newUtilizedNodes", scalingToNodesInt)
+ }
+
+ // TODO: Create event for the CRD.
+ } else {
+ // Retry after five minutes to check if the replica management commands have been completed
+ retryLaterDuration = time.Second * 5
+ }
+ }
+ // If everything succeeded, the statefulSet will have an annotation updated
+ // and the reconcile loop will be called again.
+
+ return
+ } else {
+ err = errors.New("no clusterOpMetadata annotation is present in the statefulSet")
+ logger.Error(err, "Cannot perform scaling operation when no scale-to-nodes is provided via the clusterOpMetadata")
+ return time.Second * 10, err
+ }
+}
+
+// handleManagedCloudScaleDown does the logic of a managed and "locked" cloud scale down operation.
+// This will likely take many reconcile loops to complete, as it is moving replicas away from the nodes that will be scaled down.
+func handleManagedCloudScaleDown(ctx context.Context, r *SolrCloudReconciler, instance *solrv1beta1.SolrCloud, statefulSet *appsv1.StatefulSet, scaleDownTo int, podList []corev1.Pod, logger logr.Logger) (replicaManagementComplete bool, err error) {
+ // Before doing anything to the pod, make sure that users cannot send requests to the pod anymore.
+ podStoppedReadinessConditions := map[corev1.PodConditionType]podReadinessConditionChange{
+ util.SolrIsNotStoppedReadinessCondition: {
+ reason: ScaleDown,
+ message: "Pod is being deleted, traffic to the pod must be stopped",
+ status: false,
+ },
+ }
+
+ if scaleDownTo == 0 {
+ // Delete all collections & data, the user wants no data left if scaling the solrcloud down to 0
+ // This is a much different operation to deleting the SolrCloud/StatefulSet all-together
+ replicaManagementComplete, err = evictAllPods(ctx, r, instance, podList, podStoppedReadinessConditions, logger)
Review Comment:
Question: Why is this such different than deleting the SolrCloud/StatefulSet? Isn't this going to delete all data and stop the pods?
##########
controllers/util/solr_update_util.go:
##########
@@ -503,82 +503,65 @@ func GetAllManagedSolrNodeNames(solrCloud *solr.SolrCloud) map[string]bool {
}
// EvictReplicasForPodIfNecessary takes a solr Pod and migrates all replicas off of that Pod, if the Pod is using ephemeral storage.
-// If the pod is using persistent storage, this function is a no-op.
-// This function MUST be idempotent and return the same list of pods given the same kubernetes/solr state.
-func EvictReplicasForPodIfNecessary(ctx context.Context, solrCloud *solr.SolrCloud, pod *corev1.Pod, podHasReplicas bool, logger logr.Logger) (err error, canDeletePod bool) {
- var solrDataVolume *corev1.Volume
-
- // TODO: Remove these checks after v0.7.0, since it will be taken care by the evictReplicas podReadinessCondition
- dataVolumeName := solrCloud.DataVolumeName()
- for _, volume := range pod.Spec.Volumes {
- if volume.Name == dataVolumeName {
- solrDataVolume = &volume
- break
- }
- }
-
- // Only evict if the Data volume is not persistent
- if solrDataVolume != nil && solrDataVolume.VolumeSource.PersistentVolumeClaim == nil {
- // If the Cloud has 1 or zero pods, and this is the "-0" pod, then delete the data since we can't move it anywhere else
- // Otherwise, move the replicas to other pods
- if (solrCloud.Spec.Replicas == nil || *solrCloud.Spec.Replicas < 2) && strings.HasSuffix(pod.Name, "-0") {
- queryParams := url.Values{}
- queryParams.Add("action", "DELETENODE")
- queryParams.Add("node", SolrNodeName(solrCloud, pod.Name))
- // TODO: Figure out a way to do this, since DeleteNode will not delete the last replica of every type...
- canDeletePod = true
- } else {
- requestId := "move-replicas-" + pod.Name
-
- // First check to see if the Async Replace request has started
- if asyncState, message, asyncErr := solr_api.CheckAsyncRequest(ctx, solrCloud, requestId); asyncErr != nil {
- err = asyncErr
- } else if asyncState == "notfound" {
- if podHasReplicas {
- // Submit new Replace Node request
- replaceResponse := &solr_api.SolrAsyncResponse{}
- queryParams := url.Values{}
- queryParams.Add("action", "REPLACENODE")
- queryParams.Add("parallel", "true")
- queryParams.Add("sourceNode", SolrNodeName(solrCloud, pod.Name))
- queryParams.Add("async", requestId)
- err = solr_api.CallCollectionsApi(ctx, solrCloud, queryParams, replaceResponse)
- if hasError, apiErr := solr_api.CheckForCollectionsApiError("REPLACENODE", replaceResponse.ResponseHeader); hasError {
- err = apiErr
- }
- if err == nil {
- logger.Info("Migrating all replicas off of pod before deletion.", "requestId", requestId, "pod", pod.Name)
- } else {
- logger.Error(err, "Could not migrate all replicas off of pod before deletion. Will try again later.", "requestId", requestId, "message", message)
- }
+// 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.
+func EvictReplicasForPodIfNecessary(ctx context.Context, solrCloud *solr.SolrCloud, pod *corev1.Pod, podHasReplicas bool, evictionReason string, logger logr.Logger) (err error, canDeletePod bool) {
+ logger = logger.WithValues("evictionReason", evictionReason)
+ // If the Cloud has 1 or zero pods, and this is the "-0" pod, then delete the data since we can't move it anywhere else
+ // Otherwise, move the replicas to other pods
+ if (solrCloud.Spec.Replicas == nil || *solrCloud.Spec.Replicas < 2) && strings.HasSuffix(pod.Name, "-0") {
+ queryParams := url.Values{}
+ queryParams.Add("action", "DELETENODE")
+ queryParams.Add("node", SolrNodeName(solrCloud, pod.Name))
+ // TODO: Figure out a way to do this, since DeleteNode will not delete the last replica of every type...
+ canDeletePod = true
+ } else {
+ requestId := "move-replicas-" + pod.Name
+
+ // First check to see if the Async Replace request has started
+ if asyncState, message, asyncErr := solr_api.CheckAsyncRequest(ctx, solrCloud, requestId); asyncErr != nil {
+ err = asyncErr
+ } else if asyncState == "notfound" {
+ if podHasReplicas {
+ // Submit new Replace Node request
+ replaceResponse := &solr_api.SolrAsyncResponse{}
+ queryParams := url.Values{}
+ queryParams.Add("action", "REPLACENODE")
+ queryParams.Add("parallel", "true")
+ queryParams.Add("sourceNode", SolrNodeName(solrCloud, pod.Name))
+ queryParams.Add("async", requestId)
+ err = solr_api.CallCollectionsApi(ctx, solrCloud, queryParams, replaceResponse)
+ if hasError, apiErr := solr_api.CheckForCollectionsApiError("REPLACENODE", replaceResponse.ResponseHeader); hasError {
+ err = apiErr
+ }
+ if err == nil {
+ logger.Info("Migrating all replicas off of pod before deletion.", "requestId", requestId, "pod", pod.Name)
} else {
- canDeletePod = true
+ logger.Error(err, "Could not migrate all replicas off of pod before deletion. Will try again later.", "requestId", requestId, "message", message)
}
-
} else {
- logger.Info("Found async status", "requestId", requestId, "state", asyncState)
- // Only continue to delete the pod if the ReplaceNode request is complete and successful
- if asyncState == "completed" {
- canDeletePod = true
- logger.Info("Migration of all replicas off of pod before deletion complete. Pod can now be deleted.", "pod", pod.Name)
- } else if asyncState == "failed" {
- logger.Info("Migration of all replicas off of pod before deletion failed. Will try again.", "pod", pod.Name, "message", message)
- }
+ canDeletePod = true
+ }
- // Delete the async request Id if the async request is successful or failed.
- // If the request failed, this will cause a retry since the next reconcile won't find the async requestId in Solr.
- if asyncState == "completed" || asyncState == "failed" {
- if message, err = solr_api.DeleteAsyncRequest(ctx, solrCloud, requestId); err != nil {
- logger.Error(err, "Could not delete Async request status.", "requestId", requestId, "message", message)
- } else {
- canDeletePod = false
- }
+ } else {
+ logger.Info("Found async status", "requestId", requestId, "state", asyncState)
+ // Only continue to delete the pod if the ReplaceNode request is complete and successful
+ if asyncState == "completed" {
+ canDeletePod = true
Review Comment:
Do you think it makes sense to check again for the pod before proceeding to delete it? Maybe keep doing `REPLACENODE` until it's empty? there is still a race condition, but much shorter
##########
controllers/solr_cluster_ops_util.go:
##########
@@ -0,0 +1,218 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package controllers
+
+import (
+ "context"
+ "errors"
+ solrv1beta1 "github.com/apache/solr-operator/api/v1beta1"
+ "github.com/apache/solr-operator/controllers/util"
+ "github.com/go-logr/logr"
+ appsv1 "k8s.io/api/apps/v1"
+ corev1 "k8s.io/api/core/v1"
+ "k8s.io/utils/pointer"
+ "sigs.k8s.io/controller-runtime/pkg/client"
+ "strconv"
+ "time"
+)
+
+func determineScaleClusterOpLockIfNecessary(ctx context.Context, r *SolrCloudReconciler, instance *solrv1beta1.SolrCloud, statefulSet *appsv1.StatefulSet, podList []corev1.Pod, logger logr.Logger) (clusterOpLock string, clusterOpMetadata string, retryLaterDuration time.Duration, err error) {
+ desiredPods := int(*instance.Spec.Replicas)
+ configuredPods := int(*statefulSet.Spec.Replicas)
+ if desiredPods != configuredPods {
+ scaleTo := -1
+ // Start a scaling operation
+ if desiredPods < configuredPods {
+ // Scale down!
+ // The option is enabled by default, so treat "nil" like "true"
+ if instance.Spec.Autoscaling.VacatePodsOnScaleDown == nil || *instance.Spec.Autoscaling.VacatePodsOnScaleDown {
+ if desiredPods > 0 {
+ // We only support one scaling down one pod at-a-time if not scaling down to 0 pods
+ scaleTo = configuredPods - 1
+ } else {
+ scaleTo = 0
+ }
+ } else {
+ // The cloud is not setup to use managed scale-down
+ err = scaleCloudUnmanaged(ctx, r, statefulSet, desiredPods, logger)
+ }
+ } else if desiredPods > configuredPods {
+ // Scale up!
+ // TODO: replicasScaleUp is not supported, so do not make a clusterOp out of it, just do the patch
+ err = scaleCloudUnmanaged(ctx, r, statefulSet, desiredPods, logger)
+ }
+ if scaleTo > -1 {
+ clusterOpLock = util.ScaleLock
+ clusterOpMetadata = strconv.Itoa(scaleTo)
+ }
+ }
+ return
+}
+
+func handleLockedClusterOpScale(ctx context.Context, r *SolrCloudReconciler, instance *solrv1beta1.SolrCloud, statefulSet *appsv1.StatefulSet, podList []corev1.Pod, logger logr.Logger) (retryLaterDuration time.Duration, err error) {
+ if scalingToNodes, hasAnn := statefulSet.Annotations[util.ClusterOpsMetadataAnnotation]; hasAnn {
+ if scalingToNodesInt, convErr := strconv.Atoi(scalingToNodes); convErr != nil {
+ logger.Error(convErr, "Could not convert statefulSet annotation to int for scale-down-to information", "annotation", util.ClusterOpsMetadataAnnotation, "value", scalingToNodes)
+ err = convErr
+ } else {
+ replicaManagementComplete := false
+ if scalingToNodesInt < int(*statefulSet.Spec.Replicas) {
+ // Manage scaling down the SolrCloud
+ replicaManagementComplete, err = handleManagedCloudScaleDown(ctx, r, instance, statefulSet, scalingToNodesInt, podList, logger)
+ // } else if scalingToNodesInt > int(*statefulSet.Spec.Replicas) {
+ // TODO: Utilize the scaled-up nodes in the future, however Solr does not currently have APIs for this.
+ // TODO: Think about the order of scale-up and restart when individual nodeService IPs are injected into the pods.
+ // TODO: Will likely want to do a scale-up of the service first, then do the rolling restart of the cluster, then utilize the node.
+ } else {
+ // This shouldn't happen. The ScalingToNodesAnnotation is removed when the statefulSet size changes, through a Patch.
+ // But if it does happen, we should just remove the annotation and move forward.
+ patchedStatefulSet := statefulSet.DeepCopy()
+ delete(patchedStatefulSet.Annotations, util.ClusterOpsLockAnnotation)
+ delete(patchedStatefulSet.Annotations, util.ClusterOpsMetadataAnnotation)
+ if err = r.Patch(ctx, patchedStatefulSet, client.StrategicMergeFrom(statefulSet)); err != nil {
+ logger.Error(err, "Error while patching StatefulSet to remove unneeded clusterLockOp annotation for scaling to the current amount of nodes")
+ } else {
+ statefulSet = patchedStatefulSet
+ }
+ }
+
+ // Scale down the statefulSet to represent the new number of utilizedPods, if it is lower than the current number of pods
+ // Also remove the "scalingToNodes" annotation, as that acts as a lock on the cluster, so that other operations,
+ // such as scale-up, pod updates and further scale-down cannot happen at the same time.
+ if replicaManagementComplete {
+ patchedStatefulSet := statefulSet.DeepCopy()
+ patchedStatefulSet.Spec.Replicas = pointer.Int32(int32(scalingToNodesInt))
+ delete(patchedStatefulSet.Annotations, util.ClusterOpsLockAnnotation)
+ delete(patchedStatefulSet.Annotations, util.ClusterOpsMetadataAnnotation)
+ if err = r.Patch(ctx, patchedStatefulSet, client.StrategicMergeFrom(statefulSet)); err != nil {
+ logger.Error(err, "Error while patching StatefulSet to scale down SolrCloud", "newUtilizedNodes", scalingToNodesInt)
+ }
+
+ // TODO: Create event for the CRD.
+ } else {
+ // Retry after five minutes to check if the replica management commands have been completed
+ retryLaterDuration = time.Second * 5
+ }
+ }
+ // If everything succeeded, the statefulSet will have an annotation updated
+ // and the reconcile loop will be called again.
+
+ return
+ } else {
+ err = errors.New("no clusterOpMetadata annotation is present in the statefulSet")
+ logger.Error(err, "Cannot perform scaling operation when no scale-to-nodes is provided via the clusterOpMetadata")
+ return time.Second * 10, err
+ }
+}
+
+// handleManagedCloudScaleDown does the logic of a managed and "locked" cloud scale down operation.
+// This will likely take many reconcile loops to complete, as it is moving replicas away from the nodes that will be scaled down.
+func handleManagedCloudScaleDown(ctx context.Context, r *SolrCloudReconciler, instance *solrv1beta1.SolrCloud, statefulSet *appsv1.StatefulSet, scaleDownTo int, podList []corev1.Pod, logger logr.Logger) (replicaManagementComplete bool, err error) {
+ // Before doing anything to the pod, make sure that users cannot send requests to the pod anymore.
+ podStoppedReadinessConditions := map[corev1.PodConditionType]podReadinessConditionChange{
+ util.SolrIsNotStoppedReadinessCondition: {
+ reason: ScaleDown,
+ message: "Pod is being deleted, traffic to the pod must be stopped",
+ status: false,
+ },
+ }
+
+ if scaleDownTo == 0 {
+ // Delete all collections & data, the user wants no data left if scaling the solrcloud down to 0
+ // This is a much different operation to deleting the SolrCloud/StatefulSet all-together
+ replicaManagementComplete, err = evictAllPods(ctx, r, instance, podList, podStoppedReadinessConditions, logger)
+ } else {
+ // Only evict the last pod, even if we are trying to scale down multiple pods.
+ // Scale down will happen one pod at a time.
+ replicaManagementComplete, err = evictSinglePod(ctx, r, instance, scaleDownTo, podList, podStoppedReadinessConditions, logger)
+ }
+ // TODO: It would be great to support a multi-node scale down when Solr supports evicting many SolrNodes at once.
+
+ return
+}
+
+// scaleCloudUnmanaged does simple scaling of a SolrCloud without moving replicas.
+// This is not a "locked" cluster operation, and does not block other cluster operations from taking place.
+func scaleCloudUnmanaged(ctx context.Context, r *SolrCloudReconciler, statefulSet *appsv1.StatefulSet, scaleTo int, logger logr.Logger) (err error) {
+ // Before doing anything to the pod, make sure that users cannot send requests to the pod anymore.
+ patchedStatefulSet := statefulSet.DeepCopy()
+ patchedStatefulSet.Spec.Replicas = pointer.Int32(int32(scaleTo))
+ if err = r.Patch(ctx, patchedStatefulSet, client.StrategicMergeFrom(statefulSet)); err != nil {
+ logger.Error(err, "Error while patching StatefulSet to scale SolrCloud.", "fromNodes", *statefulSet.Spec.Replicas, "toNodes", scaleTo)
+ }
+ return err
+}
+
+func evictAllPods(ctx context.Context, r *SolrCloudReconciler, instance *solrv1beta1.SolrCloud, podList []corev1.Pod, readinessConditions map[corev1.PodConditionType]podReadinessConditionChange, logger logr.Logger) (podsAreEmpty bool, err error) {
+ // If there are no pods, we can't empty them. Just return true
+ if len(podList) == 0 {
+ return true, nil
+ }
+
+ for i, pod := range podList {
+ if updatedPod, e := EnsurePodReadinessConditions(ctx, r, &pod, readinessConditions, logger); e != nil {
+ err = e
+ return
+ } else {
+ podList[i] = *updatedPod
+ }
+ }
+
+ // Delete all collections & data, the user wants no data left if scaling the solrcloud down to 0
+ // This is a much different operation to deleting the SolrCloud/StatefulSet all-together
+ // TODO: Implement delete all collections. Currently just leave the data
+ //if err, podsAreEmpty = util.DeleteAllCollectionsIfNecessary(ctx, instance, "scaleDown", logger); err != nil {
+ // logger.Error(err, "Error while evicting all collections in SolrCloud, when scaling down SolrCloud to 0 pods")
+ //}
+ podsAreEmpty = true
+
+ return
+}
+
+func evictSinglePod(ctx context.Context, r *SolrCloudReconciler, instance *solrv1beta1.SolrCloud, scaleDownTo int, podList []corev1.Pod, readinessConditions map[corev1.PodConditionType]podReadinessConditionChange, logger logr.Logger) (podIsEmpty bool, err error) {
+ var pod *corev1.Pod
+ podName := instance.GetSolrPodName(scaleDownTo)
+ for _, p := range podList {
+ if p.Name == podName {
+ pod = &p
+ break
+ }
+ }
+
+ // TODO: Get whether the pod has replicas or not
+ podHasReplicas := true
+
+ // The pod doesn't exist, we cannot empty it
Review Comment:
Question: How can this happen?
##########
docs/solr-cloud/autoscaling.md:
##########
@@ -0,0 +1,85 @@
+<!--
+ Licensed to the Apache Software Foundation (ASF) under one or more
+ contributor license agreements. See the NOTICE file distributed with
+ this work for additional information regarding copyright ownership.
+ The ASF licenses this file to You under the Apache License, Version 2.0
+ the "License"); you may not use this file except in compliance with
+ the License. You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+ -->
+
+# SolrCloud Scaling
+_Since v0.8.0_
+
+Solr Clouds are complex distributed systems, and thus require additional help when trying to scale up or down.
+
+Scaling/Autoscaling can mean different things in different situations, and this is true even within the `SolrCloud.spec.autoscaling` section.
+- Replicas can be moved when new nodes are added or when nodes need to be taken down
+- Nodes can be added/removed if more or less resources are desired.
+
+The following sections describes all the features that the Solr Operator currently supports to aid in scaling & autoscaling SolrClouds.
+
+## Configuration
+
+The `autoscaling` section in the SolrCloud CRD can be configured in the following ways
+
+```yaml
+spec:
+ autoscaling:
+ vacatePodsOnScaleDown: true # Default: true
+```
+
+## Replica Movement
+
+Solr can be scaled up & down either manually or by `HorizontalPodAutoscaler`'s, however no matter how the `SolrCloud.Spec.Replicas` value
+changes, the Solr Operator must implement this change the same way.
+
+For now Replicas are not scaled up and down themselves, they are just moved to utilize new Solr pods or vacate soon-to-be-deleted Solr pods.
+
+### Solr Pod Scale-Down
+
+When the desired number of Solr Pods that should be run `SolrCloud.Spec.Replicas` is decreased,
+the `SolrCloud.spec.autoscaling.vacatePodsOnScaleDown` option determines whether the Solr Operator should move replicas
+off of the pods that are about to be deleted.
+
+When a StatefulSet, which the Solr Operator uses to run Solr pods, has its size decreased by `x` pods, it's the last
+`x` pods that are deleted. So if a StatefulSet `tmp` has size 4, it will have pods `tmp-0`, `tmp-1`, `tmp-2` and `tmp-3`.
+If that `tmp` then is scaled down to size 2, then pods `tmp-2` and `tmp-3` will be deleted because they are `tmp`'s last pods numerically.
Review Comment:
> then pods `tmp-2` and `tmp-3` will be deleted because they are `tmp`'s last pods numerically
May be
> then pod `tmp-3` will be deleted first, followed by `tmp-2`because they are `tmp`'s last pods numerically
##########
docs/solr-cloud/autoscaling.md:
##########
@@ -0,0 +1,85 @@
+<!--
+ Licensed to the Apache Software Foundation (ASF) under one or more
+ contributor license agreements. See the NOTICE file distributed with
+ this work for additional information regarding copyright ownership.
+ The ASF licenses this file to You under the Apache License, Version 2.0
+ the "License"); you may not use this file except in compliance with
+ the License. You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+ -->
+
+# SolrCloud Scaling
+_Since v0.8.0_
+
+Solr Clouds are complex distributed systems, and thus require additional help when trying to scale up or down.
+
+Scaling/Autoscaling can mean different things in different situations, and this is true even within the `SolrCloud.spec.autoscaling` section.
+- Replicas can be moved when new nodes are added or when nodes need to be taken down
+- Nodes can be added/removed if more or less resources are desired.
+
+The following sections describes all the features that the Solr Operator currently supports to aid in scaling & autoscaling SolrClouds.
+
+## Configuration
+
+The `autoscaling` section in the SolrCloud CRD can be configured in the following ways
+
+```yaml
+spec:
+ autoscaling:
+ vacatePodsOnScaleDown: true # Default: true
+```
+
+## Replica Movement
+
+Solr can be scaled up & down either manually or by `HorizontalPodAutoscaler`'s, however no matter how the `SolrCloud.Spec.Replicas` value
+changes, the Solr Operator must implement this change the same way.
+
+For now Replicas are not scaled up and down themselves, they are just moved to utilize new Solr pods or vacate soon-to-be-deleted Solr pods.
+
+### Solr Pod Scale-Down
+
+When the desired number of Solr Pods that should be run `SolrCloud.Spec.Replicas` is decreased,
+the `SolrCloud.spec.autoscaling.vacatePodsOnScaleDown` option determines whether the Solr Operator should move replicas
+off of the pods that are about to be deleted.
+
+When a StatefulSet, which the Solr Operator uses to run Solr pods, has its size decreased by `x` pods, it's the last
+`x` pods that are deleted. So if a StatefulSet `tmp` has size 4, it will have pods `tmp-0`, `tmp-1`, `tmp-2` and `tmp-3`.
+If that `tmp` then is scaled down to size 2, then pods `tmp-2` and `tmp-3` will be deleted because they are `tmp`'s last pods numerically.
+
+If Solr has replicas placed on the pods that will be deleted as a part of the scale-down, then it has a problem.
+Solr will expect that these replicas will eventually come back online, because they are a part of the clusterState.
+However, the Solr Operator has no expectations for these replicas to come back, because the cloud has been scaled down.
+Therefore, the safest option is to move the replicas off of these pods before the scale-down operation occurs.
Review Comment:
I think this isn't very clear. I think a simpler explanation of what the operator will do would be better, something like:
```
The Solr Operator can update the cluster state to handle the scale-down operation by moving replicas off of the soon-to-be-deleted pods
```
Or something like that. I feel all the explanation of the difference between Solr and Solr Operator just adds confusion.
##########
controllers/solr_cluster_ops_util.go:
##########
@@ -0,0 +1,218 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package controllers
+
+import (
+ "context"
+ "errors"
+ solrv1beta1 "github.com/apache/solr-operator/api/v1beta1"
+ "github.com/apache/solr-operator/controllers/util"
+ "github.com/go-logr/logr"
+ appsv1 "k8s.io/api/apps/v1"
+ corev1 "k8s.io/api/core/v1"
+ "k8s.io/utils/pointer"
+ "sigs.k8s.io/controller-runtime/pkg/client"
+ "strconv"
+ "time"
+)
+
+func determineScaleClusterOpLockIfNecessary(ctx context.Context, r *SolrCloudReconciler, instance *solrv1beta1.SolrCloud, statefulSet *appsv1.StatefulSet, podList []corev1.Pod, logger logr.Logger) (clusterOpLock string, clusterOpMetadata string, retryLaterDuration time.Duration, err error) {
+ desiredPods := int(*instance.Spec.Replicas)
+ configuredPods := int(*statefulSet.Spec.Replicas)
+ if desiredPods != configuredPods {
+ scaleTo := -1
+ // Start a scaling operation
+ if desiredPods < configuredPods {
+ // Scale down!
+ // The option is enabled by default, so treat "nil" like "true"
+ if instance.Spec.Autoscaling.VacatePodsOnScaleDown == nil || *instance.Spec.Autoscaling.VacatePodsOnScaleDown {
+ if desiredPods > 0 {
+ // We only support one scaling down one pod at-a-time if not scaling down to 0 pods
+ scaleTo = configuredPods - 1
+ } else {
+ scaleTo = 0
+ }
+ } else {
+ // The cloud is not setup to use managed scale-down
+ err = scaleCloudUnmanaged(ctx, r, statefulSet, desiredPods, logger)
+ }
+ } else if desiredPods > configuredPods {
+ // Scale up!
+ // TODO: replicasScaleUp is not supported, so do not make a clusterOp out of it, just do the patch
+ err = scaleCloudUnmanaged(ctx, r, statefulSet, desiredPods, logger)
+ }
+ if scaleTo > -1 {
+ clusterOpLock = util.ScaleLock
+ clusterOpMetadata = strconv.Itoa(scaleTo)
+ }
+ }
+ return
+}
+
+func handleLockedClusterOpScale(ctx context.Context, r *SolrCloudReconciler, instance *solrv1beta1.SolrCloud, statefulSet *appsv1.StatefulSet, podList []corev1.Pod, logger logr.Logger) (retryLaterDuration time.Duration, err error) {
+ if scalingToNodes, hasAnn := statefulSet.Annotations[util.ClusterOpsMetadataAnnotation]; hasAnn {
+ if scalingToNodesInt, convErr := strconv.Atoi(scalingToNodes); convErr != nil {
+ logger.Error(convErr, "Could not convert statefulSet annotation to int for scale-down-to information", "annotation", util.ClusterOpsMetadataAnnotation, "value", scalingToNodes)
+ err = convErr
+ } else {
+ replicaManagementComplete := false
+ if scalingToNodesInt < int(*statefulSet.Spec.Replicas) {
+ // Manage scaling down the SolrCloud
+ replicaManagementComplete, err = handleManagedCloudScaleDown(ctx, r, instance, statefulSet, scalingToNodesInt, podList, logger)
+ // } else if scalingToNodesInt > int(*statefulSet.Spec.Replicas) {
+ // TODO: Utilize the scaled-up nodes in the future, however Solr does not currently have APIs for this.
+ // TODO: Think about the order of scale-up and restart when individual nodeService IPs are injected into the pods.
+ // TODO: Will likely want to do a scale-up of the service first, then do the rolling restart of the cluster, then utilize the node.
+ } else {
+ // This shouldn't happen. The ScalingToNodesAnnotation is removed when the statefulSet size changes, through a Patch.
+ // But if it does happen, we should just remove the annotation and move forward.
+ patchedStatefulSet := statefulSet.DeepCopy()
+ delete(patchedStatefulSet.Annotations, util.ClusterOpsLockAnnotation)
+ delete(patchedStatefulSet.Annotations, util.ClusterOpsMetadataAnnotation)
+ if err = r.Patch(ctx, patchedStatefulSet, client.StrategicMergeFrom(statefulSet)); err != nil {
+ logger.Error(err, "Error while patching StatefulSet to remove unneeded clusterLockOp annotation for scaling to the current amount of nodes")
+ } else {
+ statefulSet = patchedStatefulSet
+ }
+ }
+
+ // Scale down the statefulSet to represent the new number of utilizedPods, if it is lower than the current number of pods
+ // Also remove the "scalingToNodes" annotation, as that acts as a lock on the cluster, so that other operations,
+ // such as scale-up, pod updates and further scale-down cannot happen at the same time.
Review Comment:
Isn't there a `lock` annotation being used ((as I see blow)?
##########
docs/solr-cloud/autoscaling.md:
##########
@@ -0,0 +1,85 @@
+<!--
+ Licensed to the Apache Software Foundation (ASF) under one or more
+ contributor license agreements. See the NOTICE file distributed with
+ this work for additional information regarding copyright ownership.
+ The ASF licenses this file to You under the Apache License, Version 2.0
+ the "License"); you may not use this file except in compliance with
+ the License. You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+ -->
+
+# SolrCloud Scaling
+_Since v0.8.0_
+
+Solr Clouds are complex distributed systems, and thus require additional help when trying to scale up or down.
+
+Scaling/Autoscaling can mean different things in different situations, and this is true even within the `SolrCloud.spec.autoscaling` section.
+- Replicas can be moved when new nodes are added or when nodes need to be taken down
+- Nodes can be added/removed if more or less resources are desired.
+
+The following sections describes all the features that the Solr Operator currently supports to aid in scaling & autoscaling SolrClouds.
+
+## Configuration
+
+The `autoscaling` section in the SolrCloud CRD can be configured in the following ways
+
+```yaml
+spec:
+ autoscaling:
+ vacatePodsOnScaleDown: true # Default: true
+```
+
+## Replica Movement
+
+Solr can be scaled up & down either manually or by `HorizontalPodAutoscaler`'s, however no matter how the `SolrCloud.Spec.Replicas` value
+changes, the Solr Operator must implement this change the same way.
+
+For now Replicas are not scaled up and down themselves, they are just moved to utilize new Solr pods or vacate soon-to-be-deleted Solr pods.
+
+### Solr Pod Scale-Down
+
+When the desired number of Solr Pods that should be run `SolrCloud.Spec.Replicas` is decreased,
+the `SolrCloud.spec.autoscaling.vacatePodsOnScaleDown` option determines whether the Solr Operator should move replicas
+off of the pods that are about to be deleted.
+
+When a StatefulSet, which the Solr Operator uses to run Solr pods, has its size decreased by `x` pods, it's the last
+`x` pods that are deleted. So if a StatefulSet `tmp` has size 4, it will have pods `tmp-0`, `tmp-1`, `tmp-2` and `tmp-3`.
+If that `tmp` then is scaled down to size 2, then pods `tmp-2` and `tmp-3` will be deleted because they are `tmp`'s last pods numerically.
+
+If Solr has replicas placed on the pods that will be deleted as a part of the scale-down, then it has a problem.
+Solr will expect that these replicas will eventually come back online, because they are a part of the clusterState.
+However, the Solr Operator has no expectations for these replicas to come back, because the cloud has been scaled down.
+Therefore, the safest option is to move the replicas off of these pods before the scale-down operation occurs.
+
+If `autoscaling.vacatePodsOnScaleDown` option is not enabled, then whenever the `SolrCloud.Spec.Replicas` is decreased,
+that change will be reflected in the StatefulSet immediately.
+Pods will be deleted even if replicas live on those pods.
+
+If `autoscaling.vacatePodsOnScaleDown` option is enabled, which it is by default, then the following steps occur:
+1. Acquire a cluster-ops lock on the SolrCloud. (This means other cluster operations, such as a rolling restart, cannot occur during the scale down operation)
+1. Scale down the last pod.
+ 1. Mark the pod as "notReady" so that traffic is diverted away from this pod.
Review Comment:
Question: Is this only an ingress change? traffic that goes directly to the pod should continue to succeed, right? Otherwise, there will be update errors, replicas going DOWN, unnecessarily
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