| /** |
| * 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.hadoop.hbase.master.balancer; |
| |
| import java.util.ArrayDeque; |
| import java.util.ArrayList; |
| import java.util.Arrays; |
| import java.util.Collection; |
| import java.util.Deque; |
| import java.util.HashMap; |
| import java.util.LinkedList; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.Objects; |
| import java.util.Random; |
| import java.util.stream.Collectors; |
| import org.apache.hadoop.conf.Configuration; |
| import org.apache.hadoop.hbase.ClusterMetrics; |
| import org.apache.hadoop.hbase.HBaseInterfaceAudience; |
| import org.apache.hadoop.hbase.RegionMetrics; |
| import org.apache.hadoop.hbase.ServerMetrics; |
| import org.apache.hadoop.hbase.ServerName; |
| import org.apache.hadoop.hbase.TableName; |
| import org.apache.hadoop.hbase.client.BalancerDecision; |
| import org.apache.hadoop.hbase.client.RegionInfo; |
| import org.apache.hadoop.hbase.master.MasterServices; |
| import org.apache.hadoop.hbase.master.RegionPlan; |
| import org.apache.hadoop.hbase.master.balancer.BaseLoadBalancer.Cluster.Action; |
| import org.apache.hadoop.hbase.master.balancer.BaseLoadBalancer.Cluster.Action.Type; |
| import org.apache.hadoop.hbase.master.balancer.BaseLoadBalancer.Cluster.AssignRegionAction; |
| import org.apache.hadoop.hbase.master.balancer.BaseLoadBalancer.Cluster.LocalityType; |
| import org.apache.hadoop.hbase.master.balancer.BaseLoadBalancer.Cluster.MoveRegionAction; |
| import org.apache.hadoop.hbase.master.balancer.BaseLoadBalancer.Cluster.SwapRegionsAction; |
| import org.apache.hadoop.hbase.namequeues.BalancerDecisionDetails; |
| import org.apache.hadoop.hbase.namequeues.NamedQueueRecorder; |
| import org.apache.hadoop.hbase.regionserver.compactions.OffPeakHours; |
| import org.apache.hadoop.hbase.util.EnvironmentEdgeManager; |
| import org.apache.hadoop.hbase.util.ReflectionUtils; |
| import org.apache.yetus.audience.InterfaceAudience; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import org.apache.hbase.thirdparty.com.google.common.collect.Lists; |
| |
| /** |
| * <p>This is a best effort load balancer. Given a Cost function F(C) => x It will |
| * randomly try and mutate the cluster to Cprime. If F(Cprime) < F(C) then the |
| * new cluster state becomes the plan. It includes costs functions to compute the cost of:</p> |
| * <ul> |
| * <li>Region Load</li> |
| * <li>Table Load</li> |
| * <li>Data Locality</li> |
| * <li>Memstore Sizes</li> |
| * <li>Storefile Sizes</li> |
| * </ul> |
| * |
| * |
| * <p>Every cost function returns a number between 0 and 1 inclusive; where 0 is the lowest cost |
| * best solution, and 1 is the highest possible cost and the worst solution. The computed costs are |
| * scaled by their respective multipliers:</p> |
| * |
| * <ul> |
| * <li>hbase.master.balancer.stochastic.regionLoadCost</li> |
| * <li>hbase.master.balancer.stochastic.moveCost</li> |
| * <li>hbase.master.balancer.stochastic.tableLoadCost</li> |
| * <li>hbase.master.balancer.stochastic.localityCost</li> |
| * <li>hbase.master.balancer.stochastic.memstoreSizeCost</li> |
| * <li>hbase.master.balancer.stochastic.storefileSizeCost</li> |
| * </ul> |
| * |
| * <p>You can also add custom Cost function by setting the the following configuration value:</p> |
| * <ul> |
| * <li>hbase.master.balancer.stochastic.additionalCostFunctions</li> |
| * </ul> |
| * |
| * <p>All custom Cost Functions needs to extends {@link StochasticLoadBalancer.CostFunction}</p> |
| * |
| * <p>In addition to the above configurations, the balancer can be tuned by the following |
| * configuration values:</p> |
| * <ul> |
| * <li>hbase.master.balancer.stochastic.maxMoveRegions which |
| * controls what the max number of regions that can be moved in a single invocation of this |
| * balancer.</li> |
| * <li>hbase.master.balancer.stochastic.stepsPerRegion is the coefficient by which the number of |
| * regions is multiplied to try and get the number of times the balancer will |
| * mutate all servers.</li> |
| * <li>hbase.master.balancer.stochastic.maxSteps which controls the maximum number of times that |
| * the balancer will try and mutate all the servers. The balancer will use the minimum of this |
| * value and the above computation.</li> |
| * </ul> |
| * |
| * <p>This balancer is best used with hbase.master.loadbalance.bytable set to false |
| * so that the balancer gets the full picture of all loads on the cluster.</p> |
| */ |
| @InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.CONFIG) |
| @edu.umd.cs.findbugs.annotations.SuppressWarnings(value="IS2_INCONSISTENT_SYNC", |
| justification="Complaint is about costFunctions not being synchronized; not end of the world") |
| public class StochasticLoadBalancer extends BaseLoadBalancer { |
| |
| protected static final String STEPS_PER_REGION_KEY = |
| "hbase.master.balancer.stochastic.stepsPerRegion"; |
| protected static final String MAX_STEPS_KEY = |
| "hbase.master.balancer.stochastic.maxSteps"; |
| protected static final String RUN_MAX_STEPS_KEY = |
| "hbase.master.balancer.stochastic.runMaxSteps"; |
| protected static final String MAX_RUNNING_TIME_KEY = |
| "hbase.master.balancer.stochastic.maxRunningTime"; |
| protected static final String KEEP_REGION_LOADS = |
| "hbase.master.balancer.stochastic.numRegionLoadsToRemember"; |
| private static final String TABLE_FUNCTION_SEP = "_"; |
| protected static final String MIN_COST_NEED_BALANCE_KEY = |
| "hbase.master.balancer.stochastic.minCostNeedBalance"; |
| protected static final String COST_FUNCTIONS_COST_FUNCTIONS_KEY = |
| "hbase.master.balancer.stochastic.additionalCostFunctions"; |
| |
| protected static final Random RANDOM = new Random(System.currentTimeMillis()); |
| private static final Logger LOG = LoggerFactory.getLogger(StochasticLoadBalancer.class); |
| |
| Map<String, Deque<BalancerRegionLoad>> loads = new HashMap<>(); |
| |
| // values are defaults |
| private int maxSteps = 1000000; |
| private boolean runMaxSteps = false; |
| private int stepsPerRegion = 800; |
| private long maxRunningTime = 30 * 1000 * 1; // 30 seconds. |
| private int numRegionLoadsToRemember = 15; |
| private float minCostNeedBalance = 0.05f; |
| |
| private List<CandidateGenerator> candidateGenerators; |
| private CostFromRegionLoadFunction[] regionLoadFunctions; |
| private List<CostFunction> costFunctions; // FindBugs: Wants this protected; IS2_INCONSISTENT_SYNC |
| |
| // to save and report costs to JMX |
| private Double curOverallCost = 0d; |
| private Double[] tempFunctionCosts; |
| private Double[] curFunctionCosts; |
| |
| // Keep locality based picker and cost function to alert them |
| // when new services are offered |
| private LocalityBasedCandidateGenerator localityCandidateGenerator; |
| private ServerLocalityCostFunction localityCost; |
| private RackLocalityCostFunction rackLocalityCost; |
| private RegionReplicaHostCostFunction regionReplicaHostCostFunction; |
| private RegionReplicaRackCostFunction regionReplicaRackCostFunction; |
| |
| /** |
| * The constructor that pass a MetricsStochasticBalancer to BaseLoadBalancer to replace its |
| * default MetricsBalancer |
| */ |
| public StochasticLoadBalancer() { |
| super(new MetricsStochasticBalancer()); |
| } |
| |
| @Override |
| public void onConfigurationChange(Configuration conf) { |
| setConf(conf); |
| } |
| |
| @Override |
| public synchronized void setConf(Configuration conf) { |
| super.setConf(conf); |
| maxSteps = conf.getInt(MAX_STEPS_KEY, maxSteps); |
| stepsPerRegion = conf.getInt(STEPS_PER_REGION_KEY, stepsPerRegion); |
| maxRunningTime = conf.getLong(MAX_RUNNING_TIME_KEY, maxRunningTime); |
| runMaxSteps = conf.getBoolean(RUN_MAX_STEPS_KEY, runMaxSteps); |
| |
| numRegionLoadsToRemember = conf.getInt(KEEP_REGION_LOADS, numRegionLoadsToRemember); |
| minCostNeedBalance = conf.getFloat(MIN_COST_NEED_BALANCE_KEY, minCostNeedBalance); |
| if (localityCandidateGenerator == null) { |
| localityCandidateGenerator = new LocalityBasedCandidateGenerator(services); |
| } |
| localityCost = new ServerLocalityCostFunction(conf, services); |
| rackLocalityCost = new RackLocalityCostFunction(conf, services); |
| |
| if (this.candidateGenerators == null) { |
| candidateGenerators = Lists.newArrayList(); |
| candidateGenerators.add(new RandomCandidateGenerator()); |
| candidateGenerators.add(new LoadCandidateGenerator()); |
| candidateGenerators.add(localityCandidateGenerator); |
| candidateGenerators.add(new RegionReplicaRackCandidateGenerator()); |
| } |
| regionLoadFunctions = new CostFromRegionLoadFunction[] { |
| new ReadRequestCostFunction(conf), |
| new CPRequestCostFunction(conf), |
| new WriteRequestCostFunction(conf), |
| new MemStoreSizeCostFunction(conf), |
| new StoreFileCostFunction(conf) |
| }; |
| regionReplicaHostCostFunction = new RegionReplicaHostCostFunction(conf); |
| regionReplicaRackCostFunction = new RegionReplicaRackCostFunction(conf); |
| |
| costFunctions = new ArrayList<>(); |
| addCostFunction(new RegionCountSkewCostFunction(conf)); |
| addCostFunction(new PrimaryRegionCountSkewCostFunction(conf)); |
| addCostFunction(new MoveCostFunction(conf)); |
| addCostFunction(localityCost); |
| addCostFunction(rackLocalityCost); |
| addCostFunction(new TableSkewCostFunction(conf)); |
| addCostFunction(regionReplicaHostCostFunction); |
| addCostFunction(regionReplicaRackCostFunction); |
| addCostFunction(regionLoadFunctions[0]); |
| addCostFunction(regionLoadFunctions[1]); |
| addCostFunction(regionLoadFunctions[2]); |
| addCostFunction(regionLoadFunctions[3]); |
| addCostFunction(regionLoadFunctions[4]); |
| loadCustomCostFunctions(conf); |
| |
| curFunctionCosts= new Double[costFunctions.size()]; |
| tempFunctionCosts= new Double[costFunctions.size()]; |
| |
| boolean isBalancerDecisionRecording = getConf() |
| .getBoolean(BaseLoadBalancer.BALANCER_DECISION_BUFFER_ENABLED, |
| BaseLoadBalancer.DEFAULT_BALANCER_DECISION_BUFFER_ENABLED); |
| if (this.namedQueueRecorder == null && isBalancerDecisionRecording) { |
| this.namedQueueRecorder = NamedQueueRecorder.getInstance(getConf()); |
| } |
| |
| LOG.info("Loaded config; maxSteps=" + maxSteps + ", stepsPerRegion=" + stepsPerRegion + |
| ", maxRunningTime=" + maxRunningTime + ", isByTable=" + isByTable + ", CostFunctions=" + |
| Arrays.toString(getCostFunctionNames()) + " etc."); |
| } |
| |
| private void loadCustomCostFunctions(Configuration conf) { |
| String[] functionsNames = conf.getStrings(COST_FUNCTIONS_COST_FUNCTIONS_KEY); |
| |
| if (null == functionsNames) { |
| return; |
| } |
| |
| costFunctions.addAll(Arrays.stream(functionsNames).map(c -> { |
| Class<? extends CostFunction> klass = null; |
| try { |
| klass = (Class<? extends CostFunction>) Class.forName(c); |
| } catch (ClassNotFoundException e) { |
| LOG.warn("Cannot load class " + c + "': " + e.getMessage()); |
| } |
| if (null == klass) { |
| return null; |
| } |
| CostFunction reflected = ReflectionUtils.newInstance(klass, conf); |
| LOG.info( |
| "Successfully loaded custom CostFunction '" + reflected.getClass().getSimpleName() + "'"); |
| return reflected; |
| }).filter(Objects::nonNull).collect(Collectors.toList())); |
| } |
| |
| protected void setCandidateGenerators(List<CandidateGenerator> customCandidateGenerators) { |
| this.candidateGenerators = customCandidateGenerators; |
| } |
| |
| @Override |
| protected void setSlop(Configuration conf) { |
| this.slop = conf.getFloat("hbase.regions.slop", 0.001F); |
| } |
| |
| @Override |
| public synchronized void setClusterMetrics(ClusterMetrics st) { |
| super.setClusterMetrics(st); |
| updateRegionLoad(); |
| for(CostFromRegionLoadFunction cost : regionLoadFunctions) { |
| cost.setClusterMetrics(st); |
| } |
| |
| // update metrics size |
| try { |
| // by-table or ensemble mode |
| int tablesCount = isByTable ? services.getTableDescriptors().getAll().size() : 1; |
| int functionsCount = getCostFunctionNames().length; |
| |
| updateMetricsSize(tablesCount * (functionsCount + 1)); // +1 for overall |
| } catch (Exception e) { |
| LOG.error("failed to get the size of all tables", e); |
| } |
| } |
| |
| /** |
| * Update the number of metrics that are reported to JMX |
| */ |
| public void updateMetricsSize(int size) { |
| if (metricsBalancer instanceof MetricsStochasticBalancer) { |
| ((MetricsStochasticBalancer) metricsBalancer).updateMetricsSize(size); |
| } |
| } |
| |
| @Override |
| public synchronized void setMasterServices(MasterServices masterServices) { |
| super.setMasterServices(masterServices); |
| this.localityCost.setServices(masterServices); |
| this.rackLocalityCost.setServices(masterServices); |
| this.localityCandidateGenerator.setServices(masterServices); |
| } |
| |
| @Override |
| protected synchronized boolean areSomeRegionReplicasColocated(Cluster c) { |
| regionReplicaHostCostFunction.init(c); |
| if (regionReplicaHostCostFunction.cost() > 0) return true; |
| regionReplicaRackCostFunction.init(c); |
| if (regionReplicaRackCostFunction.cost() > 0) return true; |
| return false; |
| } |
| |
| @Override |
| protected boolean needsBalance(TableName tableName, Cluster cluster) { |
| ClusterLoadState cs = new ClusterLoadState(cluster.clusterState); |
| if (cs.getNumServers() < MIN_SERVER_BALANCE) { |
| if (LOG.isDebugEnabled()) { |
| LOG.debug("Not running balancer because only " + cs.getNumServers() |
| + " active regionserver(s)"); |
| } |
| return false; |
| } |
| if (areSomeRegionReplicasColocated(cluster)) { |
| return true; |
| } |
| |
| if (idleRegionServerExist(cluster)){ |
| return true; |
| } |
| |
| double total = 0.0; |
| float sumMultiplier = 0.0f; |
| for (CostFunction c : costFunctions) { |
| float multiplier = c.getMultiplier(); |
| if (multiplier <= 0) { |
| LOG.trace("{} not needed because multiplier is <= 0", c.getClass().getSimpleName()); |
| continue; |
| } |
| if (!c.isNeeded()) { |
| LOG.trace("{} not needed", c.getClass().getSimpleName()); |
| continue; |
| } |
| sumMultiplier += multiplier; |
| total += c.cost() * multiplier; |
| } |
| |
| boolean balanced = total <= 0 || sumMultiplier <= 0 || |
| (sumMultiplier > 0 && (total / sumMultiplier) < minCostNeedBalance); |
| if (LOG.isDebugEnabled()) { |
| LOG.debug("{} {}; total cost={}, sum multiplier={}; cost/multiplier to need a balance is {}", |
| balanced ? "Skipping load balancing because balanced" : "We need to load balance", |
| isByTable ? String.format("table (%s)", tableName) : "cluster", |
| total, sumMultiplier, minCostNeedBalance); |
| if (LOG.isTraceEnabled()) { |
| LOG.trace("Balance decision detailed function costs={}", functionCost()); |
| } |
| } |
| return !balanced; |
| } |
| |
| Cluster.Action nextAction(Cluster cluster) { |
| return candidateGenerators.get(RANDOM.nextInt(candidateGenerators.size())) |
| .generate(cluster); |
| } |
| |
| /** |
| * Given the cluster state this will try and approach an optimal balance. This |
| * should always approach the optimal state given enough steps. |
| */ |
| @Override |
| public synchronized List<RegionPlan> balanceTable(TableName tableName, Map<ServerName, |
| List<RegionInfo>> loadOfOneTable) { |
| List<RegionPlan> plans = balanceMasterRegions(loadOfOneTable); |
| if (plans != null || loadOfOneTable == null || loadOfOneTable.size() <= 1) { |
| return plans; |
| } |
| |
| if (masterServerName != null && loadOfOneTable.containsKey(masterServerName)) { |
| if (loadOfOneTable.size() <= 2) { |
| return null; |
| } |
| loadOfOneTable = new HashMap<>(loadOfOneTable); |
| loadOfOneTable.remove(masterServerName); |
| } |
| |
| // On clusters with lots of HFileLinks or lots of reference files, |
| // instantiating the storefile infos can be quite expensive. |
| // Allow turning this feature off if the locality cost is not going to |
| // be used in any computations. |
| RegionLocationFinder finder = null; |
| if ((this.localityCost != null && this.localityCost.getMultiplier() > 0) |
| || (this.rackLocalityCost != null && this.rackLocalityCost.getMultiplier() > 0)) { |
| finder = this.regionFinder; |
| } |
| |
| //The clusterState that is given to this method contains the state |
| //of all the regions in the table(s) (that's true today) |
| // Keep track of servers to iterate through them. |
| Cluster cluster = new Cluster(loadOfOneTable, loads, finder, rackManager); |
| |
| long startTime = EnvironmentEdgeManager.currentTime(); |
| |
| initCosts(cluster); |
| |
| if (!needsBalance(tableName, cluster)) { |
| return null; |
| } |
| |
| double currentCost = computeCost(cluster, Double.MAX_VALUE); |
| curOverallCost = currentCost; |
| System.arraycopy(tempFunctionCosts, 0, curFunctionCosts, 0, curFunctionCosts.length); |
| double initCost = currentCost; |
| double newCost; |
| |
| long computedMaxSteps; |
| if (runMaxSteps) { |
| computedMaxSteps = Math.max(this.maxSteps, |
| ((long)cluster.numRegions * (long)this.stepsPerRegion * (long)cluster.numServers)); |
| } else { |
| long calculatedMaxSteps = (long)cluster.numRegions * (long)this.stepsPerRegion * |
| (long)cluster.numServers; |
| computedMaxSteps = Math.min(this.maxSteps, calculatedMaxSteps); |
| if (calculatedMaxSteps > maxSteps) { |
| LOG.warn("calculatedMaxSteps:{} for loadbalancer's stochastic walk is larger than " |
| + "maxSteps:{}. Hence load balancing may not work well. Setting parameter " |
| + "\"hbase.master.balancer.stochastic.runMaxSteps\" to true can overcome this issue." |
| + "(This config change does not require service restart)", calculatedMaxSteps, |
| maxSteps); |
| } |
| } |
| LOG.info("start StochasticLoadBalancer.balancer, initCost=" + currentCost + ", functionCost=" |
| + functionCost() + " computedMaxSteps: " + computedMaxSteps); |
| |
| final String initFunctionTotalCosts = totalCostsPerFunc(); |
| // Perform a stochastic walk to see if we can get a good fit. |
| long step; |
| |
| for (step = 0; step < computedMaxSteps; step++) { |
| Cluster.Action action = nextAction(cluster); |
| |
| if (action.type == Type.NULL) { |
| continue; |
| } |
| |
| cluster.doAction(action); |
| updateCostsWithAction(cluster, action); |
| |
| newCost = computeCost(cluster, currentCost); |
| |
| // Should this be kept? |
| if (newCost < currentCost) { |
| currentCost = newCost; |
| |
| // save for JMX |
| curOverallCost = currentCost; |
| System.arraycopy(tempFunctionCosts, 0, curFunctionCosts, 0, curFunctionCosts.length); |
| } else { |
| // Put things back the way they were before. |
| // TODO: undo by remembering old values |
| Action undoAction = action.undoAction(); |
| cluster.doAction(undoAction); |
| updateCostsWithAction(cluster, undoAction); |
| } |
| |
| if (EnvironmentEdgeManager.currentTime() - startTime > |
| maxRunningTime) { |
| break; |
| } |
| } |
| long endTime = EnvironmentEdgeManager.currentTime(); |
| |
| metricsBalancer.balanceCluster(endTime - startTime); |
| |
| // update costs metrics |
| updateStochasticCosts(tableName, curOverallCost, curFunctionCosts); |
| if (initCost > currentCost) { |
| plans = createRegionPlans(cluster); |
| LOG.info("Finished computing new load balance plan. Computation took {}" + |
| " to try {} different iterations. Found a solution that moves " + |
| "{} regions; Going from a computed cost of {}" + |
| " to a new cost of {}", java.time.Duration.ofMillis(endTime - startTime), |
| step, plans.size(), initCost, currentCost); |
| sendRegionPlansToRingBuffer(plans, currentCost, initCost, initFunctionTotalCosts, step); |
| return plans; |
| } |
| LOG.info("Could not find a better load balance plan. Tried {} different configurations in " + |
| "{}, and did not find anything with a computed cost less than {}", step, |
| java.time.Duration.ofMillis(endTime - startTime), initCost); |
| return null; |
| } |
| |
| private void sendRegionPlansToRingBuffer(List<RegionPlan> plans, double currentCost, |
| double initCost, String initFunctionTotalCosts, long step) { |
| if (this.namedQueueRecorder != null) { |
| List<String> regionPlans = new ArrayList<>(); |
| for (RegionPlan plan : plans) { |
| regionPlans.add( |
| "table: " + plan.getRegionInfo().getTable() + " , region: " + plan.getRegionName() |
| + " , source: " + plan.getSource() + " , destination: " + plan.getDestination()); |
| } |
| BalancerDecision balancerDecision = |
| new BalancerDecision.Builder() |
| .setInitTotalCost(initCost) |
| .setInitialFunctionCosts(initFunctionTotalCosts) |
| .setComputedTotalCost(currentCost) |
| .setFinalFunctionCosts(totalCostsPerFunc()) |
| .setComputedSteps(step) |
| .setRegionPlans(regionPlans).build(); |
| namedQueueRecorder.addRecord(new BalancerDecisionDetails(balancerDecision)); |
| } |
| } |
| |
| /** |
| * update costs to JMX |
| */ |
| private void updateStochasticCosts(TableName tableName, Double overall, Double[] subCosts) { |
| if (tableName == null) return; |
| |
| // check if the metricsBalancer is MetricsStochasticBalancer before casting |
| if (metricsBalancer instanceof MetricsStochasticBalancer) { |
| MetricsStochasticBalancer balancer = (MetricsStochasticBalancer) metricsBalancer; |
| // overall cost |
| balancer.updateStochasticCost(tableName.getNameAsString(), |
| "Overall", "Overall cost", overall); |
| |
| // each cost function |
| for (int i = 0; i < costFunctions.size(); i++) { |
| CostFunction costFunction = costFunctions.get(i); |
| String costFunctionName = costFunction.getClass().getSimpleName(); |
| Double costPercent = (overall == 0) ? 0 : (subCosts[i] / overall); |
| // TODO: cost function may need a specific description |
| balancer.updateStochasticCost(tableName.getNameAsString(), costFunctionName, |
| "The percent of " + costFunctionName, costPercent); |
| } |
| } |
| } |
| |
| private void addCostFunction(CostFunction costFunction) { |
| if (costFunction.getMultiplier() > 0) { |
| costFunctions.add(costFunction); |
| } |
| } |
| |
| private String functionCost() { |
| StringBuilder builder = new StringBuilder(); |
| for (CostFunction c:costFunctions) { |
| builder.append(c.getClass().getSimpleName()); |
| builder.append(" : ("); |
| builder.append(c.getMultiplier()); |
| builder.append(", "); |
| builder.append(c.cost()); |
| builder.append("); "); |
| } |
| return builder.toString(); |
| } |
| |
| private String totalCostsPerFunc() { |
| StringBuilder builder = new StringBuilder(); |
| for (CostFunction c : costFunctions) { |
| if (c.getMultiplier() * c.cost() > 0.0) { |
| builder.append(" "); |
| builder.append(c.getClass().getSimpleName()); |
| builder.append(" : "); |
| builder.append(c.getMultiplier() * c.cost()); |
| builder.append(";"); |
| } |
| } |
| if (builder.length() > 0) { |
| builder.deleteCharAt(builder.length() - 1); |
| } |
| return builder.toString(); |
| } |
| |
| /** |
| * Create all of the RegionPlan's needed to move from the initial cluster state to the desired |
| * state. |
| * |
| * @param cluster The state of the cluster |
| * @return List of RegionPlan's that represent the moves needed to get to desired final state. |
| */ |
| private List<RegionPlan> createRegionPlans(Cluster cluster) { |
| List<RegionPlan> plans = new LinkedList<>(); |
| for (int regionIndex = 0; |
| regionIndex < cluster.regionIndexToServerIndex.length; regionIndex++) { |
| int initialServerIndex = cluster.initialRegionIndexToServerIndex[regionIndex]; |
| int newServerIndex = cluster.regionIndexToServerIndex[regionIndex]; |
| |
| if (initialServerIndex != newServerIndex) { |
| RegionInfo region = cluster.regions[regionIndex]; |
| ServerName initialServer = cluster.servers[initialServerIndex]; |
| ServerName newServer = cluster.servers[newServerIndex]; |
| |
| if (LOG.isTraceEnabled()) { |
| LOG.trace("Moving Region " + region.getEncodedName() + " from server " |
| + initialServer.getHostname() + " to " + newServer.getHostname()); |
| } |
| RegionPlan rp = new RegionPlan(region, initialServer, newServer); |
| plans.add(rp); |
| } |
| } |
| return plans; |
| } |
| |
| /** |
| * Store the current region loads. |
| */ |
| private synchronized void updateRegionLoad() { |
| // We create a new hashmap so that regions that are no longer there are removed. |
| // However we temporarily need the old loads so we can use them to keep the rolling average. |
| Map<String, Deque<BalancerRegionLoad>> oldLoads = loads; |
| loads = new HashMap<>(); |
| |
| clusterStatus.getLiveServerMetrics().forEach((ServerName sn, ServerMetrics sm) -> { |
| sm.getRegionMetrics().forEach((byte[] regionName, RegionMetrics rm) -> { |
| String regionNameAsString = RegionInfo.getRegionNameAsString(regionName); |
| Deque<BalancerRegionLoad> rLoads = oldLoads.get(regionNameAsString); |
| if (rLoads == null) { |
| rLoads = new ArrayDeque<>(numRegionLoadsToRemember + 1); |
| } else if (rLoads.size() >= numRegionLoadsToRemember) { |
| rLoads.remove(); |
| } |
| rLoads.add(new BalancerRegionLoad(rm)); |
| loads.put(regionNameAsString, rLoads); |
| }); |
| }); |
| |
| for(CostFromRegionLoadFunction cost : regionLoadFunctions) { |
| cost.setLoads(loads); |
| } |
| } |
| |
| protected void initCosts(Cluster cluster) { |
| for (CostFunction c:costFunctions) { |
| c.init(cluster); |
| } |
| } |
| |
| protected void updateCostsWithAction(Cluster cluster, Action action) { |
| for (CostFunction c : costFunctions) { |
| c.postAction(action); |
| } |
| } |
| |
| /** |
| * Get the names of the cost functions |
| */ |
| public String[] getCostFunctionNames() { |
| if (costFunctions == null) return null; |
| String[] ret = new String[costFunctions.size()]; |
| for (int i = 0; i < costFunctions.size(); i++) { |
| CostFunction c = costFunctions.get(i); |
| ret[i] = c.getClass().getSimpleName(); |
| } |
| |
| return ret; |
| } |
| |
| /** |
| * This is the main cost function. It will compute a cost associated with a proposed cluster |
| * state. All different costs will be combined with their multipliers to produce a double cost. |
| * |
| * @param cluster The state of the cluster |
| * @param previousCost the previous cost. This is used as an early out. |
| * @return a double of a cost associated with the proposed cluster state. This cost is an |
| * aggregate of all individual cost functions. |
| */ |
| protected double computeCost(Cluster cluster, double previousCost) { |
| double total = 0; |
| |
| for (int i = 0; i < costFunctions.size(); i++) { |
| CostFunction c = costFunctions.get(i); |
| this.tempFunctionCosts[i] = 0.0; |
| |
| if (c.getMultiplier() <= 0) { |
| continue; |
| } |
| |
| Float multiplier = c.getMultiplier(); |
| Double cost = c.cost(); |
| |
| this.tempFunctionCosts[i] = multiplier*cost; |
| total += this.tempFunctionCosts[i]; |
| |
| if (total > previousCost) { |
| break; |
| } |
| } |
| |
| return total; |
| } |
| |
| static class RandomCandidateGenerator extends CandidateGenerator { |
| |
| @Override |
| Cluster.Action generate(Cluster cluster) { |
| |
| int thisServer = pickRandomServer(cluster); |
| |
| // Pick the other server |
| int otherServer = pickOtherRandomServer(cluster, thisServer); |
| |
| return pickRandomRegions(cluster, thisServer, otherServer); |
| } |
| } |
| |
| /** |
| * Generates candidates which moves the replicas out of the rack for |
| * co-hosted region replicas in the same rack |
| */ |
| static class RegionReplicaRackCandidateGenerator extends RegionReplicaCandidateGenerator { |
| @Override |
| Cluster.Action generate(Cluster cluster) { |
| int rackIndex = pickRandomRack(cluster); |
| if (cluster.numRacks <= 1 || rackIndex == -1) { |
| return super.generate(cluster); |
| } |
| |
| int regionIndex = selectCoHostedRegionPerGroup( |
| cluster.primariesOfRegionsPerRack[rackIndex], |
| cluster.regionsPerRack[rackIndex], |
| cluster.regionIndexToPrimaryIndex); |
| |
| // if there are no pairs of region replicas co-hosted, default to random generator |
| if (regionIndex == -1) { |
| // default to randompicker |
| return randomGenerator.generate(cluster); |
| } |
| |
| int serverIndex = cluster.regionIndexToServerIndex[regionIndex]; |
| int toRackIndex = pickOtherRandomRack(cluster, rackIndex); |
| |
| int rand = RANDOM.nextInt(cluster.serversPerRack[toRackIndex].length); |
| int toServerIndex = cluster.serversPerRack[toRackIndex][rand]; |
| int toRegionIndex = pickRandomRegion(cluster, toServerIndex, 0.9f); |
| return getAction(serverIndex, regionIndex, toServerIndex, toRegionIndex); |
| } |
| } |
| |
| /** |
| * Base class of StochasticLoadBalancer's Cost Functions. |
| */ |
| public abstract static class CostFunction { |
| |
| private float multiplier = 0; |
| |
| protected Cluster cluster; |
| |
| public CostFunction(Configuration c) { |
| } |
| |
| boolean isNeeded() { |
| return true; |
| } |
| float getMultiplier() { |
| return multiplier; |
| } |
| |
| void setMultiplier(float m) { |
| this.multiplier = m; |
| } |
| |
| /** Called once per LB invocation to give the cost function |
| * to initialize it's state, and perform any costly calculation. |
| */ |
| void init(Cluster cluster) { |
| this.cluster = cluster; |
| } |
| |
| /** Called once per cluster Action to give the cost function |
| * an opportunity to update it's state. postAction() is always |
| * called at least once before cost() is called with the cluster |
| * that this action is performed on. */ |
| void postAction(Action action) { |
| switch (action.type) { |
| case NULL: break; |
| case ASSIGN_REGION: |
| AssignRegionAction ar = (AssignRegionAction) action; |
| regionMoved(ar.region, -1, ar.server); |
| break; |
| case MOVE_REGION: |
| MoveRegionAction mra = (MoveRegionAction) action; |
| regionMoved(mra.region, mra.fromServer, mra.toServer); |
| break; |
| case SWAP_REGIONS: |
| SwapRegionsAction a = (SwapRegionsAction) action; |
| regionMoved(a.fromRegion, a.fromServer, a.toServer); |
| regionMoved(a.toRegion, a.toServer, a.fromServer); |
| break; |
| default: |
| throw new RuntimeException("Uknown action:" + action.type); |
| } |
| } |
| |
| protected void regionMoved(int region, int oldServer, int newServer) { |
| } |
| |
| protected abstract double cost(); |
| |
| @SuppressWarnings("checkstyle:linelength") |
| /** |
| * Function to compute a scaled cost using |
| * {@link org.apache.commons.math3.stat.descriptive.DescriptiveStatistics#DescriptiveStatistics()}. |
| * It assumes that this is a zero sum set of costs. It assumes that the worst case |
| * possible is all of the elements in one region server and the rest having 0. |
| * |
| * @param stats the costs |
| * @return a scaled set of costs. |
| */ |
| protected double costFromArray(double[] stats) { |
| double totalCost = 0; |
| double total = getSum(stats); |
| |
| double count = stats.length; |
| double mean = total/count; |
| |
| // Compute max as if all region servers had 0 and one had the sum of all costs. This must be |
| // a zero sum cost for this to make sense. |
| double max = ((count - 1) * mean) + (total - mean); |
| |
| // It's possible that there aren't enough regions to go around |
| double min; |
| if (count > total) { |
| min = ((count - total) * mean) + ((1 - mean) * total); |
| } else { |
| // Some will have 1 more than everything else. |
| int numHigh = (int) (total - (Math.floor(mean) * count)); |
| int numLow = (int) (count - numHigh); |
| |
| min = (numHigh * (Math.ceil(mean) - mean)) + (numLow * (mean - Math.floor(mean))); |
| |
| } |
| min = Math.max(0, min); |
| for (int i=0; i<stats.length; i++) { |
| double n = stats[i]; |
| double diff = Math.abs(mean - n); |
| totalCost += diff; |
| } |
| |
| double scaled = scale(min, max, totalCost); |
| return scaled; |
| } |
| |
| private double getSum(double[] stats) { |
| double total = 0; |
| for(double s:stats) { |
| total += s; |
| } |
| return total; |
| } |
| |
| /** |
| * Scale the value between 0 and 1. |
| * |
| * @param min Min value |
| * @param max The Max value |
| * @param value The value to be scaled. |
| * @return The scaled value. |
| */ |
| protected double scale(double min, double max, double value) { |
| if (max <= min || value <= min) { |
| return 0; |
| } |
| if ((max - min) == 0) return 0; |
| |
| return Math.max(0d, Math.min(1d, (value - min) / (max - min))); |
| } |
| } |
| |
| /** |
| * Given the starting state of the regions and a potential ending state |
| * compute cost based upon the number of regions that have moved. |
| */ |
| static class MoveCostFunction extends CostFunction { |
| private static final String MOVE_COST_KEY = "hbase.master.balancer.stochastic.moveCost"; |
| private static final String MOVE_COST_OFFPEAK_KEY = |
| "hbase.master.balancer.stochastic.moveCost.offpeak"; |
| private static final String MAX_MOVES_PERCENT_KEY = |
| "hbase.master.balancer.stochastic.maxMovePercent"; |
| static final float DEFAULT_MOVE_COST = 7; |
| static final float DEFAULT_MOVE_COST_OFFPEAK = 3; |
| private static final int DEFAULT_MAX_MOVES = 600; |
| private static final float DEFAULT_MAX_MOVE_PERCENT = 0.25f; |
| |
| private final float maxMovesPercent; |
| private final Configuration conf; |
| |
| MoveCostFunction(Configuration conf) { |
| super(conf); |
| this.conf = conf; |
| // What percent of the number of regions a single run of the balancer can move. |
| maxMovesPercent = conf.getFloat(MAX_MOVES_PERCENT_KEY, DEFAULT_MAX_MOVE_PERCENT); |
| } |
| |
| @Override |
| protected double cost() { |
| // Move cost multiplier should be the same cost or higher than the rest of the costs to ensure |
| // that large benefits are need to overcome the cost of a move. |
| if (OffPeakHours.getInstance(conf).isOffPeakHour()) { |
| this.setMultiplier(conf.getFloat(MOVE_COST_OFFPEAK_KEY, DEFAULT_MOVE_COST_OFFPEAK)); |
| } else { |
| this.setMultiplier(conf.getFloat(MOVE_COST_KEY, DEFAULT_MOVE_COST)); |
| } |
| // Try and size the max number of Moves, but always be prepared to move some. |
| int maxMoves = Math.max((int) (cluster.numRegions * maxMovesPercent), |
| DEFAULT_MAX_MOVES); |
| |
| double moveCost = cluster.numMovedRegions; |
| |
| // Don't let this single balance move more than the max moves. |
| // This allows better scaling to accurately represent the actual cost of a move. |
| if (moveCost > maxMoves) { |
| return 1000000; // return a number much greater than any of the other cost |
| } |
| |
| return scale(0, Math.min(cluster.numRegions, maxMoves), moveCost); |
| } |
| } |
| |
| /** |
| * Compute the cost of a potential cluster state from skew in number of |
| * regions on a cluster. |
| */ |
| static class RegionCountSkewCostFunction extends CostFunction { |
| static final String REGION_COUNT_SKEW_COST_KEY = |
| "hbase.master.balancer.stochastic.regionCountCost"; |
| static final float DEFAULT_REGION_COUNT_SKEW_COST = 500; |
| |
| private double[] stats = null; |
| |
| RegionCountSkewCostFunction(Configuration conf) { |
| super(conf); |
| // Load multiplier should be the greatest as it is the most general way to balance data. |
| this.setMultiplier(conf.getFloat(REGION_COUNT_SKEW_COST_KEY, DEFAULT_REGION_COUNT_SKEW_COST)); |
| } |
| |
| @Override |
| void init(Cluster cluster) { |
| super.init(cluster); |
| LOG.debug("{} sees a total of {} servers and {} regions.", getClass().getSimpleName(), |
| cluster.numServers, cluster.numRegions); |
| if (LOG.isTraceEnabled()) { |
| for (int i =0; i < cluster.numServers; i++) { |
| LOG.trace("{} sees server '{}' has {} regions", getClass().getSimpleName(), |
| cluster.servers[i], cluster.regionsPerServer[i].length); |
| } |
| } |
| } |
| |
| @Override |
| protected double cost() { |
| if (stats == null || stats.length != cluster.numServers) { |
| stats = new double[cluster.numServers]; |
| } |
| for (int i =0; i < cluster.numServers; i++) { |
| stats[i] = cluster.regionsPerServer[i].length; |
| } |
| return costFromArray(stats); |
| } |
| } |
| |
| /** |
| * Compute the cost of a potential cluster state from skew in number of |
| * primary regions on a cluster. |
| */ |
| static class PrimaryRegionCountSkewCostFunction extends CostFunction { |
| private static final String PRIMARY_REGION_COUNT_SKEW_COST_KEY = |
| "hbase.master.balancer.stochastic.primaryRegionCountCost"; |
| private static final float DEFAULT_PRIMARY_REGION_COUNT_SKEW_COST = 500; |
| |
| private double[] stats = null; |
| |
| PrimaryRegionCountSkewCostFunction(Configuration conf) { |
| super(conf); |
| // Load multiplier should be the greatest as primary regions serve majority of reads/writes. |
| this.setMultiplier(conf.getFloat(PRIMARY_REGION_COUNT_SKEW_COST_KEY, |
| DEFAULT_PRIMARY_REGION_COUNT_SKEW_COST)); |
| } |
| |
| @Override |
| boolean isNeeded() { |
| return cluster.hasRegionReplicas; |
| } |
| |
| @Override |
| protected double cost() { |
| if (!cluster.hasRegionReplicas) { |
| return 0; |
| } |
| if (stats == null || stats.length != cluster.numServers) { |
| stats = new double[cluster.numServers]; |
| } |
| |
| for (int i = 0; i < cluster.numServers; i++) { |
| stats[i] = 0; |
| for (int regionIdx : cluster.regionsPerServer[i]) { |
| if (regionIdx == cluster.regionIndexToPrimaryIndex[regionIdx]) { |
| stats[i]++; |
| } |
| } |
| } |
| |
| return costFromArray(stats); |
| } |
| } |
| |
| /** |
| * Compute the cost of a potential cluster configuration based upon how evenly |
| * distributed tables are. |
| */ |
| static class TableSkewCostFunction extends CostFunction { |
| |
| private static final String TABLE_SKEW_COST_KEY = |
| "hbase.master.balancer.stochastic.tableSkewCost"; |
| private static final float DEFAULT_TABLE_SKEW_COST = 35; |
| |
| TableSkewCostFunction(Configuration conf) { |
| super(conf); |
| this.setMultiplier(conf.getFloat(TABLE_SKEW_COST_KEY, DEFAULT_TABLE_SKEW_COST)); |
| } |
| |
| @Override |
| protected double cost() { |
| double max = cluster.numRegions; |
| double min = ((double) cluster.numRegions) / cluster.numServers; |
| double value = 0; |
| |
| for (int i = 0; i < cluster.numMaxRegionsPerTable.length; i++) { |
| value += cluster.numMaxRegionsPerTable[i]; |
| } |
| |
| return scale(min, max, value); |
| } |
| } |
| |
| /** |
| * Compute a cost of a potential cluster configuration based upon where |
| * {@link org.apache.hadoop.hbase.regionserver.HStoreFile}s are located. |
| */ |
| static abstract class LocalityBasedCostFunction extends CostFunction { |
| |
| private final LocalityType type; |
| |
| private double bestLocality; // best case locality across cluster weighted by local data size |
| private double locality; // current locality across cluster weighted by local data size |
| |
| private MasterServices services; |
| |
| LocalityBasedCostFunction(Configuration conf, |
| MasterServices srv, |
| LocalityType type, |
| String localityCostKey, |
| float defaultLocalityCost) { |
| super(conf); |
| this.type = type; |
| this.setMultiplier(conf.getFloat(localityCostKey, defaultLocalityCost)); |
| this.services = srv; |
| this.locality = 0.0; |
| this.bestLocality = 0.0; |
| } |
| |
| /** |
| * Maps region to the current entity (server or rack) on which it is stored |
| */ |
| abstract int regionIndexToEntityIndex(int region); |
| |
| public void setServices(MasterServices srvc) { |
| this.services = srvc; |
| } |
| |
| @Override |
| void init(Cluster cluster) { |
| super.init(cluster); |
| locality = 0.0; |
| bestLocality = 0.0; |
| |
| // If no master, no computation will work, so assume 0 cost |
| if (this.services == null) { |
| return; |
| } |
| |
| for (int region = 0; region < cluster.numRegions; region++) { |
| locality += getWeightedLocality(region, regionIndexToEntityIndex(region)); |
| bestLocality += getWeightedLocality(region, getMostLocalEntityForRegion(region)); |
| } |
| |
| // We normalize locality to be a score between 0 and 1.0 representing how good it |
| // is compared to how good it could be. If bestLocality is 0, assume locality is 100 |
| // (and the cost is 0) |
| locality = bestLocality == 0 ? 1.0 : locality / bestLocality; |
| } |
| |
| @Override |
| protected void regionMoved(int region, int oldServer, int newServer) { |
| int oldEntity = type == LocalityType.SERVER ? oldServer : cluster.serverIndexToRackIndex[oldServer]; |
| int newEntity = type == LocalityType.SERVER ? newServer : cluster.serverIndexToRackIndex[newServer]; |
| if (this.services == null) { |
| return; |
| } |
| double localityDelta = getWeightedLocality(region, newEntity) - getWeightedLocality(region, oldEntity); |
| double normalizedDelta = bestLocality == 0 ? 0.0 : localityDelta / bestLocality; |
| locality += normalizedDelta; |
| } |
| |
| @Override |
| protected double cost() { |
| return 1 - locality; |
| } |
| |
| private int getMostLocalEntityForRegion(int region) { |
| return cluster.getOrComputeRegionsToMostLocalEntities(type)[region]; |
| } |
| |
| private double getWeightedLocality(int region, int entity) { |
| return cluster.getOrComputeWeightedLocality(region, entity, type); |
| } |
| |
| } |
| |
| static class ServerLocalityCostFunction extends LocalityBasedCostFunction { |
| |
| private static final String LOCALITY_COST_KEY = "hbase.master.balancer.stochastic.localityCost"; |
| private static final float DEFAULT_LOCALITY_COST = 25; |
| |
| ServerLocalityCostFunction(Configuration conf, MasterServices srv) { |
| super( |
| conf, |
| srv, |
| LocalityType.SERVER, |
| LOCALITY_COST_KEY, |
| DEFAULT_LOCALITY_COST |
| ); |
| } |
| |
| @Override |
| int regionIndexToEntityIndex(int region) { |
| return cluster.regionIndexToServerIndex[region]; |
| } |
| } |
| |
| static class RackLocalityCostFunction extends LocalityBasedCostFunction { |
| |
| private static final String RACK_LOCALITY_COST_KEY = "hbase.master.balancer.stochastic.rackLocalityCost"; |
| private static final float DEFAULT_RACK_LOCALITY_COST = 15; |
| |
| public RackLocalityCostFunction(Configuration conf, MasterServices services) { |
| super( |
| conf, |
| services, |
| LocalityType.RACK, |
| RACK_LOCALITY_COST_KEY, |
| DEFAULT_RACK_LOCALITY_COST |
| ); |
| } |
| |
| @Override |
| int regionIndexToEntityIndex(int region) { |
| return cluster.getRackForRegion(region); |
| } |
| } |
| |
| /** |
| * Base class the allows writing costs functions from rolling average of some |
| * number from RegionLoad. |
| */ |
| abstract static class CostFromRegionLoadFunction extends CostFunction { |
| |
| private ClusterMetrics clusterStatus = null; |
| private Map<String, Deque<BalancerRegionLoad>> loads = null; |
| private double[] stats = null; |
| CostFromRegionLoadFunction(Configuration conf) { |
| super(conf); |
| } |
| |
| void setClusterMetrics(ClusterMetrics status) { |
| this.clusterStatus = status; |
| } |
| |
| void setLoads(Map<String, Deque<BalancerRegionLoad>> l) { |
| this.loads = l; |
| } |
| |
| @Override |
| protected double cost() { |
| if (clusterStatus == null || loads == null) { |
| return 0; |
| } |
| |
| if (stats == null || stats.length != cluster.numServers) { |
| stats = new double[cluster.numServers]; |
| } |
| |
| for (int i =0; i < stats.length; i++) { |
| //Cost this server has from RegionLoad |
| long cost = 0; |
| |
| // for every region on this server get the rl |
| for(int regionIndex:cluster.regionsPerServer[i]) { |
| Collection<BalancerRegionLoad> regionLoadList = cluster.regionLoads[regionIndex]; |
| |
| // Now if we found a region load get the type of cost that was requested. |
| if (regionLoadList != null) { |
| cost = (long) (cost + getRegionLoadCost(regionLoadList)); |
| } |
| } |
| |
| // Add the total cost to the stats. |
| stats[i] = cost; |
| } |
| |
| // Now return the scaled cost from data held in the stats object. |
| return costFromArray(stats); |
| } |
| |
| protected double getRegionLoadCost(Collection<BalancerRegionLoad> regionLoadList) { |
| double cost = 0; |
| for (BalancerRegionLoad rl : regionLoadList) { |
| cost += getCostFromRl(rl); |
| } |
| return cost / regionLoadList.size(); |
| } |
| |
| protected abstract double getCostFromRl(BalancerRegionLoad rl); |
| } |
| |
| /** |
| * Class to be used for the subset of RegionLoad costs that should be treated as rates. |
| * We do not compare about the actual rate in requests per second but rather the rate relative |
| * to the rest of the regions. |
| */ |
| abstract static class CostFromRegionLoadAsRateFunction extends CostFromRegionLoadFunction { |
| |
| CostFromRegionLoadAsRateFunction(Configuration conf) { |
| super(conf); |
| } |
| |
| @Override |
| protected double getRegionLoadCost(Collection<BalancerRegionLoad> regionLoadList) { |
| double cost = 0; |
| double previous = 0; |
| boolean isFirst = true; |
| for (BalancerRegionLoad rl : regionLoadList) { |
| double current = getCostFromRl(rl); |
| if (isFirst) { |
| isFirst = false; |
| } else { |
| cost += current - previous; |
| } |
| previous = current; |
| } |
| return Math.max(0, cost / (regionLoadList.size() - 1)); |
| } |
| } |
| |
| /** |
| * Compute the cost of total number of read requests The more unbalanced the higher the |
| * computed cost will be. This uses a rolling average of regionload. |
| */ |
| |
| static class ReadRequestCostFunction extends CostFromRegionLoadAsRateFunction { |
| |
| private static final String READ_REQUEST_COST_KEY = |
| "hbase.master.balancer.stochastic.readRequestCost"; |
| private static final float DEFAULT_READ_REQUEST_COST = 5; |
| |
| ReadRequestCostFunction(Configuration conf) { |
| super(conf); |
| this.setMultiplier(conf.getFloat(READ_REQUEST_COST_KEY, DEFAULT_READ_REQUEST_COST)); |
| } |
| |
| @Override |
| protected double getCostFromRl(BalancerRegionLoad rl) { |
| return rl.getReadRequestsCount(); |
| } |
| } |
| |
| /** |
| * Compute the cost of total number of coprocessor requests The more unbalanced the higher the |
| * computed cost will be. This uses a rolling average of regionload. |
| */ |
| |
| static class CPRequestCostFunction extends CostFromRegionLoadAsRateFunction { |
| |
| private static final String CP_REQUEST_COST_KEY = |
| "hbase.master.balancer.stochastic.cpRequestCost"; |
| private static final float DEFAULT_CP_REQUEST_COST = 5; |
| |
| CPRequestCostFunction(Configuration conf) { |
| super(conf); |
| this.setMultiplier(conf.getFloat(CP_REQUEST_COST_KEY, DEFAULT_CP_REQUEST_COST)); |
| } |
| |
| @Override |
| protected double getCostFromRl(BalancerRegionLoad rl) { |
| return rl.getCpRequestsCount(); |
| } |
| } |
| |
| /** |
| * Compute the cost of total number of write requests. The more unbalanced the higher the |
| * computed cost will be. This uses a rolling average of regionload. |
| */ |
| static class WriteRequestCostFunction extends CostFromRegionLoadAsRateFunction { |
| |
| private static final String WRITE_REQUEST_COST_KEY = |
| "hbase.master.balancer.stochastic.writeRequestCost"; |
| private static final float DEFAULT_WRITE_REQUEST_COST = 5; |
| |
| WriteRequestCostFunction(Configuration conf) { |
| super(conf); |
| this.setMultiplier(conf.getFloat(WRITE_REQUEST_COST_KEY, DEFAULT_WRITE_REQUEST_COST)); |
| } |
| |
| @Override |
| protected double getCostFromRl(BalancerRegionLoad rl) { |
| return rl.getWriteRequestsCount(); |
| } |
| } |
| |
| /** |
| * A cost function for region replicas. We give a very high cost to hosting |
| * replicas of the same region in the same host. We do not prevent the case |
| * though, since if numReplicas > numRegionServers, we still want to keep the |
| * replica open. |
| */ |
| static class RegionReplicaHostCostFunction extends CostFunction { |
| private static final String REGION_REPLICA_HOST_COST_KEY = |
| "hbase.master.balancer.stochastic.regionReplicaHostCostKey"; |
| private static final float DEFAULT_REGION_REPLICA_HOST_COST_KEY = 100000; |
| |
| long maxCost = 0; |
| long[] costsPerGroup; // group is either server, host or rack |
| int[][] primariesOfRegionsPerGroup; |
| |
| public RegionReplicaHostCostFunction(Configuration conf) { |
| super(conf); |
| this.setMultiplier(conf.getFloat(REGION_REPLICA_HOST_COST_KEY, |
| DEFAULT_REGION_REPLICA_HOST_COST_KEY)); |
| } |
| |
| @Override |
| void init(Cluster cluster) { |
| super.init(cluster); |
| // max cost is the case where every region replica is hosted together regardless of host |
| maxCost = cluster.numHosts > 1 ? getMaxCost(cluster) : 0; |
| costsPerGroup = new long[cluster.numHosts]; |
| primariesOfRegionsPerGroup = cluster.multiServersPerHost // either server based or host based |
| ? cluster.primariesOfRegionsPerHost |
| : cluster.primariesOfRegionsPerServer; |
| for (int i = 0 ; i < primariesOfRegionsPerGroup.length; i++) { |
| costsPerGroup[i] = costPerGroup(primariesOfRegionsPerGroup[i]); |
| } |
| } |
| |
| long getMaxCost(Cluster cluster) { |
| if (!cluster.hasRegionReplicas) { |
| return 0; // short circuit |
| } |
| // max cost is the case where every region replica is hosted together regardless of host |
| int[] primariesOfRegions = new int[cluster.numRegions]; |
| System.arraycopy(cluster.regionIndexToPrimaryIndex, 0, primariesOfRegions, 0, |
| cluster.regions.length); |
| |
| Arrays.sort(primariesOfRegions); |
| |
| // compute numReplicas from the sorted array |
| return costPerGroup(primariesOfRegions); |
| } |
| |
| @Override |
| boolean isNeeded() { |
| return cluster.hasRegionReplicas; |
| } |
| |
| @Override |
| protected double cost() { |
| if (maxCost <= 0) { |
| return 0; |
| } |
| |
| long totalCost = 0; |
| for (int i = 0 ; i < costsPerGroup.length; i++) { |
| totalCost += costsPerGroup[i]; |
| } |
| return scale(0, maxCost, totalCost); |
| } |
| |
| /** |
| * For each primary region, it computes the total number of replicas in the array (numReplicas) |
| * and returns a sum of numReplicas-1 squared. For example, if the server hosts |
| * regions a, b, c, d, e, f where a and b are same replicas, and c,d,e are same replicas, it |
| * returns (2-1) * (2-1) + (3-1) * (3-1) + (1-1) * (1-1). |
| * @param primariesOfRegions a sorted array of primary regions ids for the regions hosted |
| * @return a sum of numReplicas-1 squared for each primary region in the group. |
| */ |
| protected long costPerGroup(int[] primariesOfRegions) { |
| long cost = 0; |
| int currentPrimary = -1; |
| int currentPrimaryIndex = -1; |
| // primariesOfRegions is a sorted array of primary ids of regions. Replicas of regions |
| // sharing the same primary will have consecutive numbers in the array. |
| for (int j = 0 ; j <= primariesOfRegions.length; j++) { |
| int primary = j < primariesOfRegions.length ? primariesOfRegions[j] : -1; |
| if (primary != currentPrimary) { // we see a new primary |
| int numReplicas = j - currentPrimaryIndex; |
| // square the cost |
| if (numReplicas > 1) { // means consecutive primaries, indicating co-location |
| cost += (numReplicas - 1) * (numReplicas - 1); |
| } |
| currentPrimary = primary; |
| currentPrimaryIndex = j; |
| } |
| } |
| |
| return cost; |
| } |
| |
| @Override |
| protected void regionMoved(int region, int oldServer, int newServer) { |
| if (maxCost <= 0) { |
| return; // no need to compute |
| } |
| if (cluster.multiServersPerHost) { |
| int oldHost = cluster.serverIndexToHostIndex[oldServer]; |
| int newHost = cluster.serverIndexToHostIndex[newServer]; |
| if (newHost != oldHost) { |
| costsPerGroup[oldHost] = costPerGroup(cluster.primariesOfRegionsPerHost[oldHost]); |
| costsPerGroup[newHost] = costPerGroup(cluster.primariesOfRegionsPerHost[newHost]); |
| } |
| } else { |
| costsPerGroup[oldServer] = costPerGroup(cluster.primariesOfRegionsPerServer[oldServer]); |
| costsPerGroup[newServer] = costPerGroup(cluster.primariesOfRegionsPerServer[newServer]); |
| } |
| } |
| } |
| |
| /** |
| * A cost function for region replicas for the rack distribution. We give a relatively high |
| * cost to hosting replicas of the same region in the same rack. We do not prevent the case |
| * though. |
| */ |
| static class RegionReplicaRackCostFunction extends RegionReplicaHostCostFunction { |
| private static final String REGION_REPLICA_RACK_COST_KEY = |
| "hbase.master.balancer.stochastic.regionReplicaRackCostKey"; |
| private static final float DEFAULT_REGION_REPLICA_RACK_COST_KEY = 10000; |
| |
| public RegionReplicaRackCostFunction(Configuration conf) { |
| super(conf); |
| this.setMultiplier(conf.getFloat(REGION_REPLICA_RACK_COST_KEY, |
| DEFAULT_REGION_REPLICA_RACK_COST_KEY)); |
| } |
| |
| @Override |
| void init(Cluster cluster) { |
| this.cluster = cluster; |
| if (cluster.numRacks <= 1) { |
| maxCost = 0; |
| return; // disabled for 1 rack |
| } |
| // max cost is the case where every region replica is hosted together regardless of rack |
| maxCost = getMaxCost(cluster); |
| costsPerGroup = new long[cluster.numRacks]; |
| for (int i = 0 ; i < cluster.primariesOfRegionsPerRack.length; i++) { |
| costsPerGroup[i] = costPerGroup(cluster.primariesOfRegionsPerRack[i]); |
| } |
| } |
| |
| @Override |
| protected void regionMoved(int region, int oldServer, int newServer) { |
| if (maxCost <= 0) { |
| return; // no need to compute |
| } |
| int oldRack = cluster.serverIndexToRackIndex[oldServer]; |
| int newRack = cluster.serverIndexToRackIndex[newServer]; |
| if (newRack != oldRack) { |
| costsPerGroup[oldRack] = costPerGroup(cluster.primariesOfRegionsPerRack[oldRack]); |
| costsPerGroup[newRack] = costPerGroup(cluster.primariesOfRegionsPerRack[newRack]); |
| } |
| } |
| } |
| |
| /** |
| * Compute the cost of total memstore size. The more unbalanced the higher the |
| * computed cost will be. This uses a rolling average of regionload. |
| */ |
| static class MemStoreSizeCostFunction extends CostFromRegionLoadAsRateFunction { |
| |
| private static final String MEMSTORE_SIZE_COST_KEY = |
| "hbase.master.balancer.stochastic.memstoreSizeCost"; |
| private static final float DEFAULT_MEMSTORE_SIZE_COST = 5; |
| |
| MemStoreSizeCostFunction(Configuration conf) { |
| super(conf); |
| this.setMultiplier(conf.getFloat(MEMSTORE_SIZE_COST_KEY, DEFAULT_MEMSTORE_SIZE_COST)); |
| } |
| |
| @Override |
| protected double getCostFromRl(BalancerRegionLoad rl) { |
| return rl.getMemStoreSizeMB(); |
| } |
| } |
| |
| /** |
| * Compute the cost of total open storefiles size. The more unbalanced the higher the |
| * computed cost will be. This uses a rolling average of regionload. |
| */ |
| static class StoreFileCostFunction extends CostFromRegionLoadFunction { |
| |
| private static final String STOREFILE_SIZE_COST_KEY = |
| "hbase.master.balancer.stochastic.storefileSizeCost"; |
| private static final float DEFAULT_STOREFILE_SIZE_COST = 5; |
| |
| StoreFileCostFunction(Configuration conf) { |
| super(conf); |
| this.setMultiplier(conf.getFloat(STOREFILE_SIZE_COST_KEY, DEFAULT_STOREFILE_SIZE_COST)); |
| } |
| |
| @Override |
| protected double getCostFromRl(BalancerRegionLoad rl) { |
| return rl.getStorefileSizeMB(); |
| } |
| } |
| |
| /** |
| * A helper function to compose the attribute name from tablename and costfunction name |
| */ |
| public static String composeAttributeName(String tableName, String costFunctionName) { |
| return tableName + TABLE_FUNCTION_SEP + costFunctionName; |
| } |
| } |