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svn merge -c 1417130 from trunk for HDFS-4234. Use generic code for choosing datanode in Balancer. 

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1488850 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Tsz-wo Sze 2013-06-03 05:39:04 +00:00
parent 16995501d3
commit 9b8d329e65
3 changed files with 81 additions and 194 deletions
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2
hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
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@ -128,6 +128,8 @@ Release 2.1.0-beta - UNRELEASED
HDFS-4698. Provide client-side metrics for remote reads, local reads, and
short-circuit reads. (Colin Patrick McCabe via atm)
HDFS-4234. Use generic code for choosing datanode in Balancer. (szetszwo)
OPTIMIZATIONS
BUG FIXES

267
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/balancer/Balancer.java
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@ -76,6 +76,7 @@ import org.apache.hadoop.hdfs.server.protocol.BlocksWithLocations.BlockWithLocat
import org.apache.hadoop.io.IOUtils;
import org.apache.hadoop.net.NetUtils;
import org.apache.hadoop.net.NetworkTopology;
import org.apache.hadoop.net.Node;
import org.apache.hadoop.security.token.Token;
import org.apache.hadoop.util.StringUtils;
import org.apache.hadoop.util.Time;
@ -558,7 +559,7 @@ public class Balancer {
}
/** Decide if still need to move more bytes */
protected boolean isMoveQuotaFull() {
protected boolean hasSpaceForScheduling() {
return scheduledSize<maxSize2Move;
}
@ -923,23 +924,53 @@ public class Balancer {
LOG.info(nodes.size() + " " + name + ": " + nodes);
}
/* Decide all <source, target> pairs and
/** A matcher interface for matching nodes. */
private interface Matcher {
/** Given the cluster topology, does the left node match the right node? */
boolean match(NetworkTopology cluster, Node left, Node right);
}
/** Match datanodes in the same node group. */
static final Matcher SAME_NODE_GROUP = new Matcher() {
@Override
public boolean match(NetworkTopology cluster, Node left, Node right) {
return cluster.isOnSameNodeGroup(left, right);
}
};
/** Match datanodes in the same rack. */
static final Matcher SAME_RACK = new Matcher() {
@Override
public boolean match(NetworkTopology cluster, Node left, Node right) {
return cluster.isOnSameRack(left, right);
}
};
/** Match any datanode with any other datanode. */
static final Matcher ANY_OTHER = new Matcher() {
@Override
public boolean match(NetworkTopology cluster, Node left, Node right) {
return left != right;
}
};
/**
* Decide all <source, target> pairs and
* the number of bytes to move from a source to a target
* Maximum bytes to be moved per node is
* Min(1 Band worth of bytes, MAX_SIZE_TO_MOVE).
* Return total number of bytes to move in this iteration
*/
private long chooseNodes() {
// First, match nodes on the same node group if cluster has nodegroup
// awareness
// First, match nodes on the same node group if cluster is node group aware
if (cluster.isNodeGroupAware()) {
chooseNodesOnSameNodeGroup();
chooseNodes(SAME_NODE_GROUP);
}
// Then, match nodes on the same rack
chooseNodes(true);
// At last, match nodes on different racks
chooseNodes(false);
chooseNodes(SAME_RACK);
// At last, match all remaining nodes
chooseNodes(ANY_OTHER);
assert (datanodes.size() >= sources.size()+targets.size())
: "Mismatched number of datanodes (" +
@ -953,57 +984,55 @@ public class Balancer {
}
return bytesToMove;
}
/**
* Decide all <source, target> pairs where source and target are
* on the same NodeGroup
*/
private void chooseNodesOnSameNodeGroup() {
/** Decide all <source, target> pairs according to the matcher. */
private void chooseNodes(final Matcher matcher) {
/* first step: match each overUtilized datanode (source) to
* one or more underUtilized datanodes within same NodeGroup(targets).
* one or more underUtilized datanodes (targets).
*/
chooseOnSameNodeGroup(overUtilizedDatanodes, underUtilizedDatanodes);
/* match each remaining overutilized datanode (source) to below average
* utilized datanodes within the same NodeGroup(targets).
chooseDatanodes(overUtilizedDatanodes, underUtilizedDatanodes, matcher);
/* match each remaining overutilized datanode (source) to
* below average utilized datanodes (targets).
* Note only overutilized datanodes that haven't had that max bytes to move
* satisfied in step 1 are selected
*/
chooseOnSameNodeGroup(overUtilizedDatanodes, belowAvgUtilizedDatanodes);
chooseDatanodes(overUtilizedDatanodes, belowAvgUtilizedDatanodes, matcher);
/* match each remaining underutilized datanode to above average utilized
* datanodes within the same NodeGroup.
/* match each remaining underutilized datanode (target) to
* above average utilized datanodes (source).
* Note only underutilized datanodes that have not had that max bytes to
* move satisfied in step 1 are selected.
*/
chooseOnSameNodeGroup(underUtilizedDatanodes, aboveAvgUtilizedDatanodes);
chooseDatanodes(underUtilizedDatanodes, aboveAvgUtilizedDatanodes, matcher);
}
/**
* Match two sets of nodes within the same NodeGroup, one should be source
* nodes (utilization > Avg), and the other should be destination nodes
* (utilization < Avg).
* @param datanodes
* @param candidates
* For each datanode, choose matching nodes from the candidates. Either the
* datanodes or the candidates are source nodes with (utilization > Avg), and
* the others are target nodes with (utilization < Avg).
*/
private <D extends BalancerDatanode, C extends BalancerDatanode> void
chooseOnSameNodeGroup(Collection<D> datanodes, Collection<C> candidates) {
chooseDatanodes(Collection<D> datanodes, Collection<C> candidates,
Matcher matcher) {
for (Iterator<D> i = datanodes.iterator(); i.hasNext();) {
final D datanode = i.next();
for(; chooseOnSameNodeGroup(datanode, candidates.iterator()); );
if (!datanode.isMoveQuotaFull()) {
for(; chooseForOneDatanode(datanode, candidates, matcher); );
if (!datanode.hasSpaceForScheduling()) {
i.remove();
}
}
}
/**
* Match one datanode with a set of candidates nodes within the same NodeGroup.
* For the given datanode, choose a candidate and then schedule it.
* @return true if a candidate is chosen; false if no candidates is chosen.
*/
private <T extends BalancerDatanode> boolean chooseOnSameNodeGroup(
BalancerDatanode dn, Iterator<T> candidates) {
final T chosen = chooseCandidateOnSameNodeGroup(dn, candidates);
private <C extends BalancerDatanode> boolean chooseForOneDatanode(
BalancerDatanode dn, Collection<C> candidates, Matcher matcher) {
final Iterator<C> i = candidates.iterator();
final C chosen = chooseCandidate(dn, i, matcher);
if (chosen == null) {
return false;
}
@ -1012,8 +1041,8 @@ public class Balancer {
} else {
matchSourceWithTargetToMove((Source)chosen, dn);
}
if (!chosen.isMoveQuotaFull()) {
candidates.remove();
if (!chosen.hasSpaceForScheduling()) {
i.remove();
}
return true;
}
@ -1030,19 +1059,15 @@ public class Balancer {
+source.datanode.getName() + " to " + target.datanode.getName());
}
/** choose a datanode from <code>candidates</code> within the same NodeGroup
* of <code>dn</code>.
*/
private <T extends BalancerDatanode> T chooseCandidateOnSameNodeGroup(
BalancerDatanode dn, Iterator<T> candidates) {
if (dn.isMoveQuotaFull()) {
/** Choose a candidate for the given datanode. */
private <D extends BalancerDatanode, C extends BalancerDatanode>
C chooseCandidate(D dn, Iterator<C> candidates, Matcher matcher) {
if (dn.hasSpaceForScheduling()) {
for(; candidates.hasNext(); ) {
final T c = candidates.next();
if (!c.isMoveQuotaFull()) {
final C c = candidates.next();
if (!c.hasSpaceForScheduling()) {
candidates.remove();
continue;
}
if (cluster.isOnSameNodeGroup(dn.getDatanode(), c.getDatanode())) {
} else if (matcher.match(cluster, dn.getDatanode(), c.getDatanode())) {
return c;
}
}
@ -1050,148 +1075,6 @@ public class Balancer {
return null;
}
/* if onRack is true, decide all <source, target> pairs
* where source and target are on the same rack; Otherwise
* decide all <source, target> pairs where source and target are
* on different racks
*/
private void chooseNodes(boolean onRack) {
/* first step: match each overUtilized datanode (source) to
* one or more underUtilized datanodes (targets).
*/
chooseTargets(underUtilizedDatanodes, onRack);
/* match each remaining overutilized datanode (source) to
* below average utilized datanodes (targets).
* Note only overutilized datanodes that haven't had that max bytes to move
* satisfied in step 1 are selected
*/
chooseTargets(belowAvgUtilizedDatanodes, onRack);
/* match each remaining underutilized datanode (target) to
* above average utilized datanodes (source).
* Note only underutilized datanodes that have not had that max bytes to
* move satisfied in step 1 are selected.
*/
chooseSources(aboveAvgUtilizedDatanodes, onRack);
}
/* choose targets from the target candidate list for each over utilized
* source datanode. OnRackTarget determines if the chosen target
* should be on the same rack as the source
*/
private void chooseTargets(
Collection<BalancerDatanode> targetCandidates, boolean onRackTarget ) {
for (Iterator<Source> srcIterator = overUtilizedDatanodes.iterator();
srcIterator.hasNext();) {
Source source = srcIterator.next();
while (chooseTarget(source, targetCandidates.iterator(), onRackTarget)) {
}
if (!source.isMoveQuotaFull()) {
srcIterator.remove();
}
}
return;
}
/* choose sources from the source candidate list for each under utilized
* target datanode. onRackSource determines if the chosen source
* should be on the same rack as the target
*/
private void chooseSources(
Collection<Source> sourceCandidates, boolean onRackSource) {
for (Iterator<BalancerDatanode> targetIterator =
underUtilizedDatanodes.iterator(); targetIterator.hasNext();) {
BalancerDatanode target = targetIterator.next();
while (chooseSource(target, sourceCandidates.iterator(), onRackSource)) {
}
if (!target.isMoveQuotaFull()) {
targetIterator.remove();
}
}
return;
}
/* For the given source, choose targets from the target candidate list.
* OnRackTarget determines if the chosen target
* should be on the same rack as the source
*/
private boolean chooseTarget(Source source,
Iterator<BalancerDatanode> targetCandidates, boolean onRackTarget) {
if (!source.isMoveQuotaFull()) {
return false;
}
boolean foundTarget = false;
BalancerDatanode target = null;
while (!foundTarget && targetCandidates.hasNext()) {
target = targetCandidates.next();
if (!target.isMoveQuotaFull()) {
targetCandidates.remove();
continue;
}
if (onRackTarget) {
// choose from on-rack nodes
if (cluster.isOnSameRack(source.datanode, target.datanode)) {
foundTarget = true;
}
} else {
// choose from off-rack nodes
if (!cluster.isOnSameRack(source.datanode, target.datanode)) {
foundTarget = true;
}
}
}
if (foundTarget) {
assert(target != null):"Choose a null target";
matchSourceWithTargetToMove(source, target);
if (!target.isMoveQuotaFull()) {
targetCandidates.remove();
}
return true;
}
return false;
}
/* For the given target, choose sources from the source candidate list.
* OnRackSource determines if the chosen source
* should be on the same rack as the target
*/
private boolean chooseSource(BalancerDatanode target,
Iterator<Source> sourceCandidates, boolean onRackSource) {
if (!target.isMoveQuotaFull()) {
return false;
}
boolean foundSource = false;
Source source = null;
while (!foundSource && sourceCandidates.hasNext()) {
source = sourceCandidates.next();
if (!source.isMoveQuotaFull()) {
sourceCandidates.remove();
continue;
}
if (onRackSource) {
// choose from on-rack nodes
if ( cluster.isOnSameRack(source.getDatanode(), target.getDatanode())) {
foundSource = true;
}
} else {
// choose from off-rack nodes
if (!cluster.isOnSameRack(source.datanode, target.datanode)) {
foundSource = true;
}
}
}
if (foundSource) {
assert(source != null):"Choose a null source";
matchSourceWithTargetToMove(source, target);
if ( !source.isMoveQuotaFull()) {
sourceCandidates.remove();
}
return true;
}
return false;
}
private static class BytesMoved {
private long bytesMoved = 0L;;
private synchronized void inc( long bytes ) {

6
hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/balancer/TestBalancerWithNodeGroup.java
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@ -17,13 +17,15 @@
*/
package org.apache.hadoop.hdfs.server.balancer;
import static org.junit.Assert.assertEquals;
import java.io.IOException;
import java.net.URI;
import java.util.Collection;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.TimeoutException;
import junit.framework.TestCase;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
@ -43,7 +45,7 @@ import org.junit.Test;
/**
* This class tests if a balancer schedules tasks correctly.
*/
public class TestBalancerWithNodeGroup extends TestCase {
public class TestBalancerWithNodeGroup {
private static final Log LOG = LogFactory.getLog(
"org.apache.hadoop.hdfs.TestBalancerWithNodeGroup");