HoustonPutman commented on code in PR #1650: URL: https://github.com/apache/solr/pull/1650#discussion_r1226878099
########## solr/core/src/java/org/apache/solr/cluster/placement/plugins/OrderedNodePlacementPlugin.java: ########## @@ -0,0 +1,604 @@ +/* + * 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 org.apache.solr.cluster.placement.plugins; + +import java.lang.invoke.MethodHandles; +import java.util.ArrayList; +import java.util.Collection; +import java.util.Collections; +import java.util.HashMap; +import java.util.HashSet; +import java.util.List; +import java.util.Locale; +import java.util.Map; +import java.util.Optional; +import java.util.PriorityQueue; +import java.util.Set; +import java.util.TreeSet; +import java.util.concurrent.atomic.AtomicBoolean; +import java.util.function.IntSupplier; +import java.util.stream.Collectors; +import org.apache.solr.cluster.Node; +import org.apache.solr.cluster.Replica; +import org.apache.solr.cluster.Shard; +import org.apache.solr.cluster.SolrCollection; +import org.apache.solr.cluster.placement.BalancePlan; +import org.apache.solr.cluster.placement.BalanceRequest; +import org.apache.solr.cluster.placement.DeleteCollectionRequest; +import org.apache.solr.cluster.placement.DeleteReplicasRequest; +import org.apache.solr.cluster.placement.DeleteShardsRequest; +import org.apache.solr.cluster.placement.ModificationRequest; +import org.apache.solr.cluster.placement.PlacementContext; +import org.apache.solr.cluster.placement.PlacementException; +import org.apache.solr.cluster.placement.PlacementModificationException; +import org.apache.solr.cluster.placement.PlacementPlan; +import org.apache.solr.cluster.placement.PlacementPlugin; +import org.apache.solr.cluster.placement.PlacementRequest; +import org.apache.solr.cluster.placement.ReplicaPlacement; +import org.apache.solr.common.util.CollectionUtil; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +public abstract class OrderedNodePlacementPlugin implements PlacementPlugin { + private static final Logger log = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass()); + + @Override + public List<PlacementPlan> computePlacements( + Collection<PlacementRequest> requests, PlacementContext placementContext) + throws PlacementException { + List<PlacementPlan> placementPlans = new ArrayList<>(requests.size()); + Set<Node> allNodes = new HashSet<>(); + Set<SolrCollection> allCollections = new HashSet<>(); + for (PlacementRequest request : requests) { + allNodes.addAll(request.getTargetNodes()); + allCollections.add(request.getCollection()); + } + Collection<WeightedNode> weightedNodes = + getWeightedNodes(placementContext, allNodes, allCollections, true).values(); + for (PlacementRequest request : requests) { + int totalReplicasPerShard = 0; + for (Replica.ReplicaType rt : Replica.ReplicaType.values()) { + totalReplicasPerShard += request.getCountReplicasToCreate(rt); + } + + List<WeightedNode> nodesForRequest = + weightedNodes.stream() + .filter(wn -> request.getTargetNodes().contains(wn.getNode())) + .collect(Collectors.toList()); + + Set<ReplicaPlacement> replicaPlacements = + CollectionUtil.newHashSet(totalReplicasPerShard * request.getShardNames().size()); + + SolrCollection solrCollection = request.getCollection(); + // Now place randomly all replicas of all shards on available nodes + for (String shardName : request.getShardNames()) { + for (Replica.ReplicaType replicaType : Replica.ReplicaType.values()) { + int replicaCount = request.getCountReplicasToCreate(replicaType); + if (replicaCount == 0) { + continue; + } + if (log.isDebugEnabled()) { + log.debug( + "Placing replicas for Collection: {}, Shard: {}, ReplicaType: {}", + solrCollection.getName(), + shardName, + replicaType); + } + Replica pr = + PlacementPlugin.createProjectedReplica(solrCollection, shardName, replicaType, null); + PriorityQueue<WeightedNode> nodesForReplicaType = new PriorityQueue<>(); + nodesForRequest.stream() + .filter(n -> n.canAddReplica(pr)) + .forEach( + n -> { + n.sortByRelevantWeightWithReplica(pr); + n.addToSortedCollection(nodesForReplicaType); + }); + + int replicasPlaced = 0; + while (!nodesForReplicaType.isEmpty() && replicasPlaced < replicaCount) { + WeightedNode node = nodesForReplicaType.poll(); + if (!node.canAddReplica(pr)) { + if (log.isDebugEnabled()) { + log.debug( + "Node can no longer accept replica, removing from selection list: {}", + node.getNode()); + } + continue; + } + if (node.hasWeightChangedSinceSort()) { + if (log.isDebugEnabled()) { + log.debug( + "Node's sort is out-of-date, adding back to selection list: {}", + node.getNode()); + } + node.addToSortedCollection(nodesForReplicaType); + // The node will be re-sorted, + // so go back to the top of the loop to get the new lowest-sorted node + continue; + } + if (log.isDebugEnabled()) { + log.debug("Node chosen to host replica: {}", node.getNode()); + } + + boolean needsToResortAll = + node.addReplica( + PlacementPlugin.createProjectedReplica( + solrCollection, shardName, replicaType, node.getNode())); + replicasPlaced += 1; + replicaPlacements.add( + placementContext + .getPlacementPlanFactory() + .createReplicaPlacement( + solrCollection, shardName, node.getNode(), replicaType)); + // Only update the priorityQueue if there are still replicas to be placed + if (replicasPlaced < replicaCount) { + if (needsToResortAll) { + if (log.isDebugEnabled()) { + log.debug("Replica addition requires re-sorting of entire selection list"); + } + List<WeightedNode> nodeList = new ArrayList<>(nodesForReplicaType); + nodesForReplicaType.clear(); + nodeList.forEach(n -> n.addToSortedCollection(nodesForReplicaType)); + } + // Add the chosen node back to the list if it can accept another replica of the + // shard/replicaType. + // The default implementation of "canAddReplica()" returns false for replicas + // of shards that the node already contains, so this will usually be false. + if (node.canAddReplica(pr)) { + nodesForReplicaType.add(node); + } + } + } + + if (replicasPlaced < replicaCount) { + throw new PlacementException( + String.format( + Locale.ROOT, + "Not enough eligible nodes to place %d replica(s) of type %s for shard %s of collection %s. Only able to place %d replicas.", + replicaCount, + replicaType, + shardName, + solrCollection.getName(), + replicasPlaced)); + } + } + } + + placementPlans.add( + placementContext + .getPlacementPlanFactory() + .createPlacementPlan(request, replicaPlacements)); + } + return placementPlans; + } + + @Override + public BalancePlan computeBalancing( + BalanceRequest balanceRequest, PlacementContext placementContext) throws PlacementException { + Map<Replica, Node> replicaMovements = new HashMap<>(); + TreeSet<WeightedNode> orderedNodes = new TreeSet<>(); + Collection<WeightedNode> weightedNodes = + getWeightedNodes( + placementContext, + balanceRequest.getNodes(), + placementContext.getCluster().collections(), + true) + .values(); + // This is critical to store the last sort weight for this node + weightedNodes.forEach( + node -> { + node.sortWithoutChanges(); + node.addToSortedCollection(orderedNodes); + }); + + // While the node with the least cores still has room to take a replica from the node with the + // most cores, loop + Map<Replica, Node> newReplicaMovements = new HashMap<>(); + ArrayList<WeightedNode> traversedHighNodes = new ArrayList<>(orderedNodes.size() - 1); + while (orderedNodes.size() > 1 + && orderedNodes.first().calcWeight() < orderedNodes.last().calcWeight()) { + WeightedNode lowestWeight = orderedNodes.pollFirst(); + if (lowestWeight == null) { + break; + } + if (lowestWeight.hasWeightChangedSinceSort()) { + if (log.isDebugEnabled()) { + log.debug( + "Re-sorting lowest weighted node: {}, sorting weight is out-of-date.", + lowestWeight.getNode().getName()); + } + // Re-sort this node and go back to find the lowest weight + lowestWeight.addToSortedCollection(orderedNodes); + continue; + } + if (log.isDebugEnabled()) { + log.debug( + "Lowest weighted node: {}, weight: {}", + lowestWeight.getNode().getName(), + lowestWeight.calcWeight()); + } + + newReplicaMovements.clear(); + // If a compatible node was found to move replicas, break and find the lowest weighted node + // again + while (newReplicaMovements.isEmpty() + && !orderedNodes.isEmpty() + && orderedNodes.last().calcWeight() > lowestWeight.calcWeight() + 1) { + WeightedNode highestWeight = orderedNodes.pollLast(); + if (highestWeight == null) { + break; + } + if (highestWeight.hasWeightChangedSinceSort()) { + if (log.isDebugEnabled()) { + log.debug( + "Re-sorting highest weighted node: {}, sorting weight is out-of-date.", + highestWeight.getNode().getName()); + } + // Re-sort this node and go back to find the highest weight + highestWeight.addToSortedCollection(orderedNodes); + continue; + } + if (log.isDebugEnabled()) { + log.debug( + "Highest weighted node: {}, weight: {}", + highestWeight.getNode().getName(), + highestWeight.calcWeight()); + } + + traversedHighNodes.add(highestWeight); + // select a replica from the node with the most cores to move to the node with the least + // cores + Set<Replica> availableReplicasToMove = highestWeight.getAllReplicasOnNode(); + int combinedNodeWeights = highestWeight.calcWeight() + lowestWeight.calcWeight(); + for (Replica r : availableReplicasToMove) { + // Only continue if the replica can be removed from the old node and moved to the new node + if (!highestWeight.canRemoveReplicas(Set.of(r)).isEmpty() + || !lowestWeight.canAddReplica(r)) { + continue; + } + lowestWeight.addReplica(r); + highestWeight.removeReplica(r); + int lowestWeightWithReplica = lowestWeight.calcWeight(); + int highestWeightWithoutReplica = highestWeight.calcWeight(); + if (log.isDebugEnabled()) { + log.debug( + "Replica: {}, toNode weight with replica: {}, fromNode weight without replica: {}", + r.getReplicaName(), + lowestWeightWithReplica, + highestWeightWithoutReplica); + } + + // If the combined weight of both nodes is lower after the move, make the move. + // Otherwise, make the move if it doesn't cause the weight of the higher node to + // go below the weight of the lower node, because that is over-correction. + if (highestWeightWithoutReplica + lowestWeightWithReplica >= combinedNodeWeights + && highestWeightWithoutReplica < lowestWeightWithReplica) { + // Undo the move + lowestWeight.removeReplica(r); + highestWeight.addReplica(r); + continue; + } + if (log.isDebugEnabled()) { + log.debug( + "Replica Movement chosen. From: {}, To: {}, Replica: {}", + highestWeight.getNode().getName(), + lowestWeight.getNode().getName(), + r); + } + newReplicaMovements.put(r, lowestWeight.getNode()); + + // Do not go beyond here, do another loop and see if other nodes can move replicas. + // It might end up being the same nodes in the next loop that end up moving another + // replica, but that's ok. + break; + } + } + traversedHighNodes.forEach(n -> n.addToSortedCollection(orderedNodes)); + traversedHighNodes.clear(); + if (newReplicaMovements.size() > 0) { + replicaMovements.putAll(newReplicaMovements); + // There are no replicas to move to the lowestWeight, remove it from our loop + lowestWeight.addToSortedCollection(orderedNodes); + } + } + + return placementContext + .getBalancePlanFactory() + .createBalancePlan(balanceRequest, replicaMovements); + } + + protected Map<Node, WeightedNode> getWeightedNodes( + PlacementContext placementContext, + Set<Node> nodes, + Iterable<SolrCollection> relevantCollections, + boolean skipNodesWithErrors) + throws PlacementException { + Map<Node, WeightedNode> weightedNodes = + getBaseWeightedNodes(placementContext, nodes, relevantCollections, skipNodesWithErrors); + + for (SolrCollection collection : placementContext.getCluster().collections()) { + for (Shard shard : collection.shards()) { + for (Replica replica : shard.replicas()) { + WeightedNode weightedNode = weightedNodes.get(replica.getNode()); + if (weightedNode != null) { + weightedNode.initReplica(replica); + } + } + } + } + + return weightedNodes; + } + + protected abstract Map<Node, WeightedNode> getBaseWeightedNodes( + PlacementContext placementContext, + Set<Node> nodes, + Iterable<SolrCollection> relevantCollections, + boolean skipNodesWithErrors) + throws PlacementException; + + @Override + public void verifyAllowedModification( + ModificationRequest modificationRequest, PlacementContext placementContext) + throws PlacementException { + if (modificationRequest instanceof DeleteShardsRequest) { + log.warn("DeleteShardsRequest not implemented yet, skipping: {}", modificationRequest); + } else if (modificationRequest instanceof DeleteCollectionRequest) { + verifyDeleteCollection((DeleteCollectionRequest) modificationRequest, placementContext); + } else if (modificationRequest instanceof DeleteReplicasRequest) { + verifyDeleteReplicas((DeleteReplicasRequest) modificationRequest, placementContext); + } else { + log.warn("unsupported request type, skipping: {}", modificationRequest); + } + } + + protected void verifyDeleteCollection( + DeleteCollectionRequest deleteCollectionRequest, PlacementContext placementContext) + throws PlacementException { + // NO-OP + } + + protected void verifyDeleteReplicas( + DeleteReplicasRequest deleteReplicasRequest, PlacementContext placementContext) + throws PlacementException { + Map<Node, List<Replica>> nodesRepresented = + deleteReplicasRequest.getReplicas().stream() + .collect(Collectors.groupingBy(Replica::getNode)); + + Map<Node, WeightedNode> weightedNodes = + getWeightedNodes( + placementContext, + nodesRepresented.keySet(), + placementContext.getCluster().collections(), + false); + + PlacementModificationException placementModificationException = + new PlacementModificationException("delete replica(s) rejected"); + for (Map.Entry<Node, List<Replica>> entry : nodesRepresented.entrySet()) { + WeightedNode node = weightedNodes.get(entry.getKey()); + if (node == null) { + entry + .getValue() + .forEach( + replica -> + placementModificationException.addRejectedModification( + replica.toString(), + "could not load information for node: " + entry.getKey().getName())); + } else { + node.canRemoveReplicas(entry.getValue()) + .forEach( + (replica, reason) -> + placementModificationException.addRejectedModification( + replica.toString(), reason)); + } + } + if (!placementModificationException.getRejectedModifications().isEmpty()) { + throw placementModificationException; + } + } + + /** + * A class that determines the weight of a given node and the replicas that reside on it. + * + * <p>The OrderedNodePlacementPlugin uses the weights determined here to place and balance + * replicas across the cluster. + * + * @lucene.experimental + */ + public abstract static class WeightedNode implements Comparable<WeightedNode> { + private final Node node; + private final Map<String, Map<String, Set<Replica>>> replicas; + private IntSupplier sortWeightCalculator; + private int lastSortedWeight; + + public WeightedNode(Node node) { + this.node = node; + this.replicas = new HashMap<>(); + this.lastSortedWeight = 0; + this.sortWeightCalculator = this::calcWeight; + } + + public void sortByRelevantWeightWithReplica(Replica replica) { + sortWeightCalculator = () -> calcRelevantWeightWithReplica(replica); + } + + public void sortWithoutChanges() { + sortWeightCalculator = this::calcWeight; + } + + public Node getNode() { + return node; + } + + public Set<Replica> getAllReplicasOnNode() { + return replicas.values().stream() + .flatMap(shard -> shard.values().stream()) + .flatMap(Collection::stream) + .collect(Collectors.toSet()); + } + + public Set<String> getCollectionsOnNode() { + return replicas.keySet(); + } + + public boolean hasCollectionOnNode(String collection) { + return replicas.containsKey(collection); + } + + public Set<String> getShardsOnNode(String collection) { + return replicas.getOrDefault(collection, Collections.emptyMap()).keySet(); + } + + public boolean hasShardOnNode(Shard shard) { + return replicas + .getOrDefault(shard.getCollection().getName(), Collections.emptyMap()) + .containsKey(shard.getShardName()); + } + + public Set<Replica> getReplicasForShardOnNode(Shard shard) { + return Optional.ofNullable(replicas.get(shard.getCollection().getName())) + .map(m -> m.get(shard.getShardName())) + .orElseGet(Collections::emptySet); + } + + public void addToSortedCollection(Collection<WeightedNode> collection) { Review Comment: Unfortunately not, because `Collection` is the lowest common ancestor of `TreeSet` and `PriorityQueue`. -- This is an automated message from the Apache Git Service. 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