From 1e763d521f589b746dda8f97b1b740000781f74f Mon Sep 17 00:00:00 2001 From: clarax Date: Mon, 12 Jul 2021 10:10:24 -0700 Subject: [PATCH] HBASE-25973 Balancer should explain progress in a better way in log (#3356) Signed-off-by: stack Signed-off-by: Sean Busbey --- .../balancer/StochasticLoadBalancer.java | 97 ++++++++++--------- .../apache/hadoop/hbase/master/HMaster.java | 2 + 2 files changed, 54 insertions(+), 45 deletions(-) diff --git a/hbase-balancer/src/main/java/org/apache/hadoop/hbase/master/balancer/StochasticLoadBalancer.java b/hbase-balancer/src/main/java/org/apache/hadoop/hbase/master/balancer/StochasticLoadBalancer.java index a3136182376..2e6364fe5d4 100644 --- a/hbase-balancer/src/main/java/org/apache/hadoop/hbase/master/balancer/StochasticLoadBalancer.java +++ b/hbase-balancer/src/main/java/org/apache/hadoop/hbase/master/balancer/StochasticLoadBalancer.java @@ -129,7 +129,8 @@ public class StochasticLoadBalancer extends BaseLoadBalancer { private List candidateGenerators; private List costFunctions; // FindBugs: Wants this protected; IS2_INCONSISTENT_SYNC - + // To save currently configed sum of multiplier. Defaulted at 1 for cases that carry high cost + private float sumMultiplier = 1.0f; // to save and report costs to JMX private double curOverallCost = 0d; private double[] tempFunctionCosts; @@ -220,7 +221,6 @@ public class StochasticLoadBalancer extends BaseLoadBalancer { regionReplicaHostCostFunction = new RegionReplicaHostCostFunction(conf); regionReplicaRackCostFunction = new RegionReplicaRackCostFunction(conf); - costFunctions = new ArrayList<>(); addCostFunction(new RegionCountSkewCostFunction(conf)); addCostFunction(new PrimaryRegionCountSkewCostFunction(conf)); @@ -303,54 +303,55 @@ public class StochasticLoadBalancer extends BaseLoadBalancer { boolean needsBalance(TableName tableName, BalancerClusterState 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() + LOG.info("Not running balancer because only " + cs.getNumServers() + " active regionserver(s)"); - } sendRejectionReasonToRingBuffer(() -> "The number of RegionServers " + cs.getNumServers() + " < MIN_SERVER_BALANCE(" + MIN_SERVER_BALANCE + ")", null); return false; } if (areSomeRegionReplicasColocated(cluster)) { + LOG.info("Running balancer because at least one server hosts replicas of the same region."); return true; } if (idleRegionServerExist(cluster)){ + LOG.info("Running balancer because cluster has idle server(s)."); return true; } + sumMultiplier = 0.0f; 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; - } + double cost = c.cost(); if (!c.isNeeded()) { LOG.trace("{} not needed", c.getClass().getSimpleName()); continue; } + total += cost * multiplier; sumMultiplier += multiplier; - total += c.cost() * multiplier; + } + if (sumMultiplier <= 0) { + LOG.error("At least one cost function needs a multiplier > 0. For example, set " + + "hbase.master.balancer.stochastic.regionCountCost to a positive value or default"); + return false; } - boolean balanced = total <= 0 || sumMultiplier <= 0 || - (sumMultiplier > 0 && (total / sumMultiplier) < minCostNeedBalance); + boolean balanced = (total / sumMultiplier < minCostNeedBalance); + if (balanced) { final double calculatedTotal = total; - final double calculatedMultiplier = sumMultiplier; - sendRejectionReasonToRingBuffer(() -> getBalanceReason(calculatedTotal, calculatedMultiplier), - costFunctions); - } - 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()); - } + sendRejectionReasonToRingBuffer(() -> + getBalanceReason(calculatedTotal, sumMultiplier), costFunctions); + LOG.info("{} - skipping load balancing because weighted average imbalance={} <= " + + "threshold({}). If you want more aggressive balancing, either lower " + + "hbase.master.balancer.stochastic.minCostNeedBalance from {} or increase the relative " + + "multiplier(s) of the specific cost function(s). functionCost={}", + isByTable ? "Table specific ("+tableName+")" : "Cluster wide", total / sumMultiplier, + minCostNeedBalance, minCostNeedBalance, functionCost()); + } else { + LOG.info("{} - Calculating plan. may take up to {}ms to complete.", + isByTable ? "Table specific ("+tableName+")" : "Cluster wide", maxRunningTime); } return !balanced; } @@ -384,8 +385,8 @@ public class StochasticLoadBalancer extends BaseLoadBalancer { // Allow turning this feature off if the locality cost is not going to // be used in any computations. RegionHDFSBlockLocationFinder finder = null; - if ((this.localityCost != null && this.localityCost.getMultiplier() > 0) - || (this.rackLocalityCost != null && this.rackLocalityCost.getMultiplier() > 0)) { + if ((this.localityCost != null) + || (this.rackLocalityCost != null)) { finder = this.regionFinder; } @@ -423,8 +424,9 @@ public class StochasticLoadBalancer extends BaseLoadBalancer { maxSteps); } } - LOG.info("start StochasticLoadBalancer.balancer, initCost=" + currentCost + ", functionCost=" - + functionCost() + " computedMaxSteps: " + computedMaxSteps); + LOG.info("Start StochasticLoadBalancer.balancer, initial weighted average imbalance={}, " + + "functionCost={} computedMaxSteps={}", + currentCost / sumMultiplier, functionCost(), computedMaxSteps); final String initFunctionTotalCosts = totalCostsPerFunc(); // Perform a stochastic walk to see if we can get a good fit. @@ -470,17 +472,18 @@ public class StochasticLoadBalancer extends BaseLoadBalancer { updateStochasticCosts(tableName, curOverallCost, curFunctionCosts); if (initCost > currentCost) { List 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); + LOG.info("Finished computing new moving plan. Computation took {} ms" + + " to try {} different iterations. Found a solution that moves " + + "{} regions; Going from a computed imbalance of {}" + + " to a new imbalance of {}. ", + endTime - startTime, step, plans.size(), + initCost / sumMultiplier, currentCost / sumMultiplier); 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); + LOG.info("Could not find a better moving plan. Tried {} different configurations in " + + "{} ms, and did not find anything with an imbalance score less than {}", step, + endTime - startTime, initCost / sumMultiplier); return null; } @@ -490,8 +493,7 @@ public class StochasticLoadBalancer extends BaseLoadBalancer { BalancerRejection.Builder builder = new BalancerRejection.Builder().setReason(reason.get()); if (costFunctions != null) { for (CostFunction c : costFunctions) { - float multiplier = c.getMultiplier(); - if (multiplier <= 0 || !c.isNeeded()) { + if (!c.isNeeded()) { continue; } builder.addCostFuncInfo(c.getClass().getName(), c.cost(), c.getMultiplier()); @@ -545,7 +547,8 @@ public class StochasticLoadBalancer extends BaseLoadBalancer { } private void addCostFunction(CostFunction costFunction) { - if (costFunction.getMultiplier() > 0) { + float multiplier = costFunction.getMultiplier(); + if (multiplier > 0) { costFunctions.add(costFunction); } } @@ -556,9 +559,13 @@ public class StochasticLoadBalancer extends BaseLoadBalancer { builder.append(c.getClass().getSimpleName()); builder.append(" : ("); if (c.isNeeded()) { - builder.append(c.getMultiplier()); + builder.append("multiplier=" + c.getMultiplier()); builder.append(", "); - builder.append(c.cost()); + double cost = c.cost(); + builder.append("imbalance=" + cost); + if (cost < minCostNeedBalance) { + builder.append(", balanced"); + } } else { builder.append("not needed"); } @@ -570,7 +577,7 @@ public class StochasticLoadBalancer extends BaseLoadBalancer { private String totalCostsPerFunc() { StringBuilder builder = new StringBuilder(); for (CostFunction c : costFunctions) { - if (c.getMultiplier() <= 0 || !c.isNeeded()) { + if (!c.isNeeded()) { continue; } double cost = c.getMultiplier() * c.cost(); @@ -654,7 +661,7 @@ public class StochasticLoadBalancer extends BaseLoadBalancer { allowedOnPath = ".*(/src/test/.*|StochasticLoadBalancer).java") void updateCostsWithAction(BalancerClusterState cluster, BalanceAction action) { for (CostFunction c : costFunctions) { - if (c.getMultiplier() > 0 && c.isNeeded()) { + if (c.isNeeded()) { c.postAction(action); } } @@ -693,7 +700,7 @@ public class StochasticLoadBalancer extends BaseLoadBalancer { CostFunction c = costFunctions.get(i); this.tempFunctionCosts[i] = 0.0; - if (c.getMultiplier() <= 0 || !c.isNeeded()) { + if (!c.isNeeded()) { continue; } diff --git a/hbase-server/src/main/java/org/apache/hadoop/hbase/master/HMaster.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/master/HMaster.java index ba38a19e8c5..1791ce4c4a5 100644 --- a/hbase-server/src/main/java/org/apache/hadoop/hbase/master/HMaster.java +++ b/hbase-server/src/main/java/org/apache/hadoop/hbase/master/HMaster.java @@ -1874,6 +1874,8 @@ public class HMaster extends HRegionServer implements MasterServices { } } } + LOG.info("Balancer is going into sleep until next period in {}ms", getConfiguration() + .getInt(HConstants.HBASE_BALANCER_PERIOD, HConstants.DEFAULT_HBASE_BALANCER_PERIOD)); return successRegionPlans; }