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new 0b7630b HBASE-26309 Balancer tends to move regions to the server at
the end o… (#3812)
0b7630b is described below
commit 0b7630bc1f392832eba36a62ef273d603fe75b56
Author: clarax <[email protected]>
AuthorDate: Tue Nov 2 19:27:46 2021 -0700
HBASE-26309 Balancer tends to move regions to the server at the end o…
(#3812)
Signed-off-by: Duo Zhang <[email protected]>
---
.../hbase/master/balancer/BaseLoadBalancer.java | 7 +++
.../master/balancer/LoadCandidateGenerator.java | 54 ++++++++++++++++------
.../master/balancer/StochasticLoadBalancer.java | 7 +--
.../hbase/master/balancer/BalancerTestBase.java | 39 +++++++++++++++-
...ochasticLoadBalancerRegionReplicaWithRacks.java | 34 ++++++++++++--
5 files changed, 120 insertions(+), 21 deletions(-)
diff --git
a/hbase-server/src/main/java/org/apache/hadoop/hbase/master/balancer/BaseLoadBalancer.java
b/hbase-server/src/main/java/org/apache/hadoop/hbase/master/balancer/BaseLoadBalancer.java
index 2e55b9b..03713c9 100644
---
a/hbase-server/src/main/java/org/apache/hadoop/hbase/master/balancer/BaseLoadBalancer.java
+++
b/hbase-server/src/main/java/org/apache/hadoop/hbase/master/balancer/BaseLoadBalancer.java
@@ -338,6 +338,7 @@ public abstract class BaseLoadBalancer implements
LoadBalancer {
racks[entry.getValue()] = entry.getKey();
}
+ LOG.debug("Hosts are {} racks are {}", hostsToIndex, racksToIndex);
for (Entry<ServerName, List<RegionInfo>> entry :
clusterState.entrySet()) {
int serverIndex = serversToIndex.get(entry.getKey().getAddress());
regionPerServerIndex = serverIndexToRegionsOffset[serverIndex];
@@ -365,6 +366,7 @@ public abstract class BaseLoadBalancer implements
LoadBalancer {
serversPerHost[i] = new int[serversPerHostList.get(i).size()];
for (int j = 0; j < serversPerHost[i].length; j++) {
serversPerHost[i][j] = serversPerHostList.get(i).get(j);
+ LOG.debug("server {} is on host
{}",serversPerHostList.get(i).get(j), i);
}
if (serversPerHost[i].length > 1) {
multiServersPerHost = true;
@@ -375,6 +377,7 @@ public abstract class BaseLoadBalancer implements
LoadBalancer {
serversPerRack[i] = new int[serversPerRackList.get(i).size()];
for (int j = 0; j < serversPerRack[i].length; j++) {
serversPerRack[i][j] = serversPerRackList.get(i).get(j);
+ LOG.info("server {} is on rack {}",serversPerRackList.get(i).get(j),
i);
}
}
@@ -960,6 +963,10 @@ public abstract class BaseLoadBalancer implements
LoadBalancer {
private Comparator<Integer> numRegionsComparator =
Comparator.comparingInt(this::getNumRegions);
+ public Comparator<Integer> getNumRegionsComparator() {
+ return numRegionsComparator;
+ }
+
int getLowestLocalityRegionOnServer(int serverIndex) {
if (regionFinder != null) {
float lowestLocality = 1.0f;
diff --git
a/hbase-server/src/main/java/org/apache/hadoop/hbase/master/balancer/LoadCandidateGenerator.java
b/hbase-server/src/main/java/org/apache/hadoop/hbase/master/balancer/LoadCandidateGenerator.java
index d60065f..38114b9 100644
---
a/hbase-server/src/main/java/org/apache/hadoop/hbase/master/balancer/LoadCandidateGenerator.java
+++
b/hbase-server/src/main/java/org/apache/hadoop/hbase/master/balancer/LoadCandidateGenerator.java
@@ -18,13 +18,13 @@
package org.apache.hadoop.hbase.master.balancer;
+import java.util.concurrent.ThreadLocalRandom;
import org.apache.yetus.audience.InterfaceAudience;
@InterfaceAudience.Private
class LoadCandidateGenerator extends CandidateGenerator {
- @Override
- BaseLoadBalancer.Cluster.Action generate(BaseLoadBalancer.Cluster cluster) {
+ @Override BaseLoadBalancer.Cluster.Action generate(BaseLoadBalancer.Cluster
cluster) {
cluster.sortServersByRegionCount();
int thisServer = pickMostLoadedServer(cluster, -1);
int otherServer = pickLeastLoadedServer(cluster, thisServer);
@@ -34,27 +34,53 @@ class LoadCandidateGenerator extends CandidateGenerator {
private int pickLeastLoadedServer(final BaseLoadBalancer.Cluster cluster,
int thisServer) {
Integer[] servers = cluster.serverIndicesSortedByRegionCount;
- int index = 0;
- while (servers[index] == null || servers[index] == thisServer) {
- index++;
- if (index == servers.length) {
- return -1;
+ int selectedIndex = -1;
+ double currentLargestRandom = -1;
+ for (int i = 0; i < servers.length; i++) {
+ if (servers[i] == null || servers[i] == thisServer) {
+ continue;
+ }
+ if (selectedIndex != -1 &&
cluster.getNumRegionsComparator().compare(servers[i],
+ servers[selectedIndex]) != 0) {
+ // Exhausted servers of the same region count
+ break;
+ }
+ // we don't know how many servers have the same region count, we will
randomly select one
+ // using a simplified inline reservoir sampling by assignmening a random
number to stream
+ // data and choose the greatest one.
(http://gregable.com/2007/10/reservoir-sampling.html)
+ double currentRandom = ThreadLocalRandom.current().nextDouble();
+ if (currentRandom > currentLargestRandom) {
+ selectedIndex = i;
+ currentLargestRandom = currentRandom;
}
}
- return servers[index];
+ return selectedIndex == -1 ? -1 : servers[selectedIndex];
}
private int pickMostLoadedServer(final BaseLoadBalancer.Cluster cluster, int
thisServer) {
Integer[] servers = cluster.serverIndicesSortedByRegionCount;
- int index = servers.length - 1;
- while (servers[index] == null || servers[index] == thisServer) {
- index--;
- if (index < 0) {
- return -1;
+ int selectedIndex = -1;
+ double currentLargestRandom = -1;
+ for (int i = servers.length - 1; i >= 0; i--) {
+ if (servers[i] == null || servers[i] == thisServer) {
+ continue;
+ }
+ if (selectedIndex != -1
+ && cluster.getNumRegionsComparator().compare(servers[i],
servers[selectedIndex]) != 0) {
+ // Exhausted servers of the same region count
+ break;
+ }
+ // we don't know how many servers have the same region count, we will
randomly select one
+ // using a simplified inline reservoir sampling by assignmening a random
number to stream
+ // data and choose the greatest one.
(http://gregable.com/2007/10/reservoir-sampling.html)
+ double currentRandom = ThreadLocalRandom.current().nextDouble();
+ if (currentRandom > currentLargestRandom) {
+ selectedIndex = i;
+ currentLargestRandom = currentRandom;
}
}
- return servers[index];
+ return selectedIndex == -1 ? -1 : servers[selectedIndex];
}
}
diff --git
a/hbase-server/src/main/java/org/apache/hadoop/hbase/master/balancer/StochasticLoadBalancer.java
b/hbase-server/src/main/java/org/apache/hadoop/hbase/master/balancer/StochasticLoadBalancer.java
index de706cb..d58bdf0 100644
---
a/hbase-server/src/main/java/org/apache/hadoop/hbase/master/balancer/StochasticLoadBalancer.java
+++
b/hbase-server/src/main/java/org/apache/hadoop/hbase/master/balancer/StochasticLoadBalancer.java
@@ -510,9 +510,10 @@ public class StochasticLoadBalancer extends
BaseLoadBalancer {
plans = createRegionPlans(cluster);
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);
+ "{} regions; Going from a computed imbalance of {}" +
+ " to a new imbalance of {}. funtionCost={}",
+ endTime - startTime, step, plans.size(),
+ initCost / sumMultiplier, currentCost / sumMultiplier, functionCost());
sendRegionPlansToRingBuffer(plans, currentCost, initCost,
initFunctionTotalCosts, step);
return plans;
diff --git
a/hbase-server/src/test/java/org/apache/hadoop/hbase/master/balancer/BalancerTestBase.java
b/hbase-server/src/test/java/org/apache/hadoop/hbase/master/balancer/BalancerTestBase.java
index 685088f..a4823ae 100644
---
a/hbase-server/src/test/java/org/apache/hadoop/hbase/master/balancer/BalancerTestBase.java
+++
b/hbase-server/src/test/java/org/apache/hadoop/hbase/master/balancer/BalancerTestBase.java
@@ -571,7 +571,7 @@ public class BalancerTestBase {
List<ServerAndLoad> balancedCluster = reconcile(list, plans, serverMap);
// Print out the cluster loads to make debugging easier.
- LOG.info("Mock Balance : " + printMock(balancedCluster));
+ LOG.info("Mock after Balance : " + printMock(balancedCluster));
if (assertFullyBalanced) {
assertClusterAsBalanced(balancedCluster);
@@ -587,6 +587,43 @@ public class BalancerTestBase {
}
}
+ protected void testWithClusterWithIteration(Map<ServerName,
List<RegionInfo>> serverMap,
+ RackManager rackManager, boolean assertFullyBalanced, boolean
assertFullyBalancedForReplicas) {
+ List<ServerAndLoad> list = convertToList(serverMap);
+ LOG.info("Mock Cluster : " + printMock(list) + " " + printStats(list));
+
+ loadBalancer.setRackManager(rackManager);
+ // Run the balancer.
+ Map<TableName, Map<ServerName, List<RegionInfo>>> LoadOfAllTable =
+ (Map) mockClusterServersWithTables(serverMap);
+ List<RegionPlan> plans = loadBalancer.balanceCluster(LoadOfAllTable);
+ assertNotNull("Initial cluster balance should produce plans.", plans);
+
+ List<ServerAndLoad> balancedCluster = null;
+ // Run through iteration until done. Otherwise will be killed as test time
out
+ while (plans != null && (assertFullyBalanced ||
assertFullyBalancedForReplicas)) {
+ // Apply the plan to the mock cluster.
+ balancedCluster = reconcile(list, plans, serverMap);
+
+ // Print out the cluster loads to make debugging easier.
+ LOG.info("Mock after balance: " + printMock(balancedCluster));
+
+ LoadOfAllTable = (Map) mockClusterServersWithTables(serverMap);
+ plans = loadBalancer.balanceCluster(LoadOfAllTable);
+ }
+
+ // Print out the cluster loads to make debugging easier.
+ LOG.info("Mock Final balance: " + printMock(balancedCluster));
+
+ if (assertFullyBalanced) {
+ assertNull("Given a requirement to be fully balanced, second attempt at
plans should " +
+ "produce none.", plans);
+ }
+ if (assertFullyBalancedForReplicas) {
+ assertRegionReplicaPlacement(serverMap, rackManager);
+ }
+ }
+
protected Map<ServerName, List<RegionInfo>> createServerMap(int numNodes,
int numRegions,
int
numRegionsPerServer,
diff --git
a/hbase-server/src/test/java/org/apache/hadoop/hbase/master/balancer/TestStochasticLoadBalancerRegionReplicaWithRacks.java
b/hbase-server/src/test/java/org/apache/hadoop/hbase/master/balancer/TestStochasticLoadBalancerRegionReplicaWithRacks.java
index b7532eb..648d860 100644
---
a/hbase-server/src/test/java/org/apache/hadoop/hbase/master/balancer/TestStochasticLoadBalancerRegionReplicaWithRacks.java
+++
b/hbase-server/src/test/java/org/apache/hadoop/hbase/master/balancer/TestStochasticLoadBalancerRegionReplicaWithRacks.java
@@ -17,6 +17,7 @@
*/
package org.apache.hadoop.hbase.master.balancer;
+import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.apache.hadoop.hbase.HBaseClassTestRule;
@@ -38,6 +39,8 @@ public class TestStochasticLoadBalancerRegionReplicaWithRacks
extends BalancerTe
private static class ForTestRackManager extends RackManager {
int numRacks;
+ Map<String, Integer> serverIndexes = new HashMap<String, Integer>();
+ int numServers = 0;
public ForTestRackManager(int numRacks) {
this.numRacks = numRacks;
@@ -45,13 +48,18 @@ public class
TestStochasticLoadBalancerRegionReplicaWithRacks extends BalancerTe
@Override
public String getRack(ServerName server) {
- return "rack_" + (server.hashCode() % numRacks);
+ String key = server.getServerName();
+ if (!serverIndexes.containsKey(key)) {
+ serverIndexes.put(key, numServers++);
+ }
+ return "rack_" + serverIndexes.get(key) % numRacks;
}
}
@Test
public void testRegionReplicationOnMidClusterWithRacks() {
- conf.setLong(StochasticLoadBalancer.MAX_STEPS_KEY, 10000000L);
+ conf.setLong(StochasticLoadBalancer.MAX_STEPS_KEY, 100000000L);
+ conf.setBoolean("hbase.master.balancer.stochastic.runMaxSteps", true);
conf.setFloat("hbase.master.balancer.stochastic.maxMovePercent", 1.0f);
conf.setLong("hbase.master.balancer.stochastic.maxRunningTime", 120 *
1000); // 120 sec
loadBalancer.setConf(conf);
@@ -65,6 +73,26 @@ public class
TestStochasticLoadBalancerRegionReplicaWithRacks extends BalancerTe
createServerMap(numNodes, numRegions, numRegionsPerServer,
replication, numTables);
RackManager rm = new ForTestRackManager(numRacks);
- testWithCluster(serverMap, rm, false, true);
+ testWithClusterWithIteration(serverMap, rm, true, true);
+ }
+
+ @Test
+ public void testRegionReplicationOnLargeClusterWithRacks() {
+ conf.setBoolean("hbase.master.balancer.stochastic.runMaxSteps", false);
+ conf.setLong(StochasticLoadBalancer.MAX_STEPS_KEY, 5000L);
+ conf.setFloat("hbase.master.balancer.stochastic.maxMovePercent", 1.0f);
+ conf.setLong("hbase.master.balancer.stochastic.maxRunningTime", 10 *
1000); // 10 sec
+ loadBalancer.onConfigurationChange(conf);
+ int numNodes = 100;
+ int numRegions = numNodes * 30;
+ int replication = 3; // 3 replicas per region
+ int numRegionsPerServer = 28;
+ int numTables = 1;
+ int numRacks = 4; // all replicas should be on a different rack
+ Map<ServerName, List<RegionInfo>> serverMap =
+ createServerMap(numNodes, numRegions, numRegionsPerServer, replication,
numTables);
+ RackManager rm = new ForTestRackManager(numRacks);
+
+ testWithClusterWithIteration(serverMap, rm, true, true);
}
}
