HDFS-7891. A block placement policy with best rack failure tolerance. Contributed by Walter Su
This commit is contained in:
Tsz-Wo Nicholas Sze
parent
4308910eed
commit
9595cc003c
|
|
@ -323,6 +323,9 @@ Release 2.8.0 - UNRELEASED
|
|||
|
||||
NEW FEATURES
|
||||
|
||||
HDFS-7891. A block placement policy with best rack failure tolerance.
|
||||
(Walter Su via szetszwo)
|
||||
|
||||
IMPROVEMENTS
|
||||
|
||||
HDFS-3918. EditLogTailer shouldn't log WARN when other node
|
||||
|
|
|
|||
|
|
@ -237,7 +237,7 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
|
|||
* is independent of the number of chosen nodes, as it is calculated
|
||||
* using the target number of replicas.
|
||||
*/
|
||||
private int[] getMaxNodesPerRack(int numOfChosen, int numOfReplicas) {
|
||||
protected int[] getMaxNodesPerRack(int numOfChosen, int numOfReplicas) {
|
||||
int clusterSize = clusterMap.getNumOfLeaves();
|
||||
int totalNumOfReplicas = numOfChosen + numOfReplicas;
|
||||
if (totalNumOfReplicas > clusterSize) {
|
||||
|
|
|
|||
|
|
@ -0,0 +1,154 @@
|
|||
/**
|
||||
* 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.hdfs.server.blockmanagement;
|
||||
|
||||
import org.apache.hadoop.classification.InterfaceAudience;
|
||||
import org.apache.hadoop.fs.StorageType;
|
||||
import org.apache.hadoop.net.Node;
|
||||
import org.apache.hadoop.net.NodeBase;
|
||||
|
||||
import java.util.*;
|
||||
|
||||
/**
|
||||
* The class is responsible for choosing the desired number of targets
|
||||
* for placing block replicas.
|
||||
* The strategy is that it tries its best to place the replicas to most racks.
|
||||
*/
|
||||
@InterfaceAudience.Private
|
||||
public class BlockPlacementPolicyRackFaultTolarent extends BlockPlacementPolicyDefault {
|
||||
|
||||
@Override
|
||||
protected int[] getMaxNodesPerRack(int numOfChosen, int numOfReplicas) {
|
||||
int clusterSize = clusterMap.getNumOfLeaves();
|
||||
int totalNumOfReplicas = numOfChosen + numOfReplicas;
|
||||
if (totalNumOfReplicas > clusterSize) {
|
||||
numOfReplicas -= (totalNumOfReplicas-clusterSize);
|
||||
totalNumOfReplicas = clusterSize;
|
||||
}
|
||||
// No calculation needed when there is only one rack or picking one node.
|
||||
int numOfRacks = clusterMap.getNumOfRacks();
|
||||
if (numOfRacks == 1 || totalNumOfReplicas <= 1) {
|
||||
return new int[] {numOfReplicas, totalNumOfReplicas};
|
||||
}
|
||||
if(totalNumOfReplicas<numOfRacks){
|
||||
return new int[] {numOfReplicas, 1};
|
||||
}
|
||||
int maxNodesPerRack = (totalNumOfReplicas - 1) / numOfRacks + 1;
|
||||
return new int[] {numOfReplicas, maxNodesPerRack};
|
||||
}
|
||||
|
||||
/**
|
||||
* Choose numOfReplicas in order:
|
||||
* 1. If total replica expected is less than numOfRacks in cluster, it choose
|
||||
* randomly.
|
||||
* 2. If total replica expected is bigger than numOfRacks, it choose:
|
||||
* 2a. Fill each rack exactly (maxNodesPerRack-1) replicas.
|
||||
* 2b. For some random racks, place one more replica to each one of them, until
|
||||
* numOfReplicas have been chosen. <br>
|
||||
* In the end, the difference of the numbers of replicas for each two racks
|
||||
* is no more than 1.
|
||||
* Either way it always prefer local storage.
|
||||
* @return local node of writer
|
||||
*/
|
||||
@Override
|
||||
protected Node chooseTargetInOrder(int numOfReplicas,
|
||||
Node writer,
|
||||
final Set<Node> excludedNodes,
|
||||
final long blocksize,
|
||||
final int maxNodesPerRack,
|
||||
final List<DatanodeStorageInfo> results,
|
||||
final boolean avoidStaleNodes,
|
||||
final boolean newBlock,
|
||||
EnumMap<StorageType, Integer> storageTypes)
|
||||
throws NotEnoughReplicasException {
|
||||
int totalReplicaExpected = results.size() + numOfReplicas;
|
||||
int numOfRacks = clusterMap.getNumOfRacks();
|
||||
if (totalReplicaExpected < numOfRacks ||
|
||||
totalReplicaExpected % numOfRacks == 0) {
|
||||
writer = chooseOnce(numOfReplicas, writer, excludedNodes, blocksize,
|
||||
maxNodesPerRack, results, avoidStaleNodes, storageTypes);
|
||||
return writer;
|
||||
}
|
||||
|
||||
assert totalReplicaExpected > (maxNodesPerRack -1) * numOfRacks;
|
||||
|
||||
// Calculate numOfReplicas for filling each rack exactly (maxNodesPerRack-1)
|
||||
// replicas.
|
||||
HashMap<String, Integer> rackCounts = new HashMap<>();
|
||||
for (DatanodeStorageInfo dsInfo : results) {
|
||||
String rack = dsInfo.getDatanodeDescriptor().getNetworkLocation();
|
||||
Integer count = rackCounts.get(rack);
|
||||
if (count != null) {
|
||||
rackCounts.put(rack, count + 1);
|
||||
} else {
|
||||
rackCounts.put(rack, 1);
|
||||
}
|
||||
}
|
||||
int excess = 0; // Sum of the above (maxNodesPerRack-1) part of nodes in results
|
||||
for (int count : rackCounts.values()) {
|
||||
if (count > maxNodesPerRack -1) {
|
||||
excess += count - (maxNodesPerRack -1);
|
||||
}
|
||||
}
|
||||
numOfReplicas = Math.min(totalReplicaExpected - results.size(),
|
||||
(maxNodesPerRack -1) * numOfRacks - (results.size() - excess));
|
||||
|
||||
// Fill each rack exactly (maxNodesPerRack-1) replicas.
|
||||
writer = chooseOnce(numOfReplicas, writer, new HashSet<>(excludedNodes),
|
||||
blocksize, maxNodesPerRack -1, results, avoidStaleNodes, storageTypes);
|
||||
|
||||
for (DatanodeStorageInfo resultStorage : results) {
|
||||
addToExcludedNodes(resultStorage.getDatanodeDescriptor(), excludedNodes);
|
||||
}
|
||||
|
||||
// For some racks, place one more replica to each one of them.
|
||||
numOfReplicas = totalReplicaExpected - results.size();
|
||||
chooseOnce(numOfReplicas, writer, excludedNodes, blocksize,
|
||||
maxNodesPerRack, results, avoidStaleNodes, storageTypes);
|
||||
|
||||
return writer;
|
||||
}
|
||||
|
||||
/**
|
||||
* Randomly choose <i>numOfReplicas</i> targets from the given <i>scope</i>.
|
||||
* Except that 1st replica prefer local storage.
|
||||
* @return local node of writer.
|
||||
*/
|
||||
private Node chooseOnce(int numOfReplicas,
|
||||
Node writer,
|
||||
final Set<Node> excludedNodes,
|
||||
final long blocksize,
|
||||
final int maxNodesPerRack,
|
||||
final List<DatanodeStorageInfo> results,
|
||||
final boolean avoidStaleNodes,
|
||||
EnumMap<StorageType, Integer> storageTypes)
|
||||
throws NotEnoughReplicasException {
|
||||
if (numOfReplicas == 0) {
|
||||
return writer;
|
||||
}
|
||||
writer = chooseLocalStorage(writer, excludedNodes, blocksize,
|
||||
maxNodesPerRack, results, avoidStaleNodes, storageTypes, true)
|
||||
.getDatanodeDescriptor();
|
||||
if (--numOfReplicas == 0) {
|
||||
return writer;
|
||||
}
|
||||
chooseRandom(numOfReplicas, NodeBase.ROOT, excludedNodes, blocksize,
|
||||
maxNodesPerRack, results, avoidStaleNodes, storageTypes);
|
||||
return writer;
|
||||
}
|
||||
}
|
||||
|
|
@ -0,0 +1,209 @@
|
|||
/**
|
||||
* 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.hdfs.server.namenode;
|
||||
|
||||
import org.apache.hadoop.conf.Configuration;
|
||||
import org.apache.hadoop.fs.CreateFlag;
|
||||
import org.apache.hadoop.fs.permission.FsPermission;
|
||||
import org.apache.hadoop.fs.permission.PermissionStatus;
|
||||
import org.apache.hadoop.hdfs.DFSConfigKeys;
|
||||
import org.apache.hadoop.hdfs.DFSUtil;
|
||||
import org.apache.hadoop.hdfs.HdfsConfiguration;
|
||||
import org.apache.hadoop.hdfs.MiniDFSCluster;
|
||||
import org.apache.hadoop.hdfs.protocol.DatanodeInfo;
|
||||
import org.apache.hadoop.hdfs.protocol.HdfsFileStatus;
|
||||
import org.apache.hadoop.hdfs.protocol.LocatedBlock;
|
||||
import org.apache.hadoop.hdfs.server.blockmanagement.BlockPlacementPolicy;
|
||||
import org.apache.hadoop.hdfs.server.blockmanagement.BlockPlacementPolicyRackFaultTolarent;
|
||||
import org.apache.hadoop.hdfs.server.protocol.NamenodeProtocols;
|
||||
import org.apache.hadoop.net.StaticMapping;
|
||||
import org.junit.After;
|
||||
import org.junit.Before;
|
||||
import org.junit.Test;
|
||||
|
||||
import java.io.IOException;
|
||||
import java.util.*;
|
||||
|
||||
import static org.junit.Assert.assertEquals;
|
||||
import static org.junit.Assert.assertTrue;
|
||||
|
||||
public class TestBlockPlacementPolicyRackFaultTolarent {
|
||||
|
||||
private static final int DEFAULT_BLOCK_SIZE = 1024;
|
||||
private MiniDFSCluster cluster = null;
|
||||
private NamenodeProtocols nameNodeRpc = null;
|
||||
private FSNamesystem namesystem = null;
|
||||
private PermissionStatus perm = null;
|
||||
|
||||
@Before
|
||||
public void setup() throws IOException {
|
||||
StaticMapping.resetMap();
|
||||
Configuration conf = new HdfsConfiguration();
|
||||
final ArrayList<String> rackList = new ArrayList<String>();
|
||||
final ArrayList<String> hostList = new ArrayList<String>();
|
||||
for (int i = 0; i < 10; i++) {
|
||||
for (int j = 0; j < 2; j++) {
|
||||
rackList.add("/rack" + i);
|
||||
hostList.add("/host" + i + j);
|
||||
}
|
||||
}
|
||||
conf.setClass(DFSConfigKeys.DFS_BLOCK_REPLICATOR_CLASSNAME_KEY,
|
||||
BlockPlacementPolicyRackFaultTolarent.class,
|
||||
BlockPlacementPolicy.class);
|
||||
conf.setLong(DFSConfigKeys.DFS_BLOCK_SIZE_KEY, DEFAULT_BLOCK_SIZE);
|
||||
conf.setInt(DFSConfigKeys.DFS_BYTES_PER_CHECKSUM_KEY, DEFAULT_BLOCK_SIZE / 2);
|
||||
cluster = new MiniDFSCluster.Builder(conf)
|
||||
.numDataNodes(hostList.size())
|
||||
.racks(rackList.toArray(new String[rackList.size()]))
|
||||
.hosts(hostList.toArray(new String[hostList.size()]))
|
||||
.build();
|
||||
cluster.waitActive();
|
||||
nameNodeRpc = cluster.getNameNodeRpc();
|
||||
namesystem = cluster.getNamesystem();
|
||||
perm = new PermissionStatus("TestBlockPlacementPolicyEC", null,
|
||||
FsPermission.getDefault());
|
||||
}
|
||||
|
||||
@After
|
||||
public void teardown() {
|
||||
if (cluster != null) {
|
||||
cluster.shutdown();
|
||||
}
|
||||
}
|
||||
|
||||
@Test
|
||||
public void testChooseTarget() throws Exception {
|
||||
doTestChooseTargetNormalCase();
|
||||
doTestChooseTargetSpecialCase();
|
||||
}
|
||||
|
||||
private void doTestChooseTargetNormalCase() throws Exception {
|
||||
String clientMachine = "client.foo.com";
|
||||
short[][] testSuite = {
|
||||
{3, 2}, {3, 7}, {3, 8}, {3, 10}, {9, 1}, {10, 1}, {10, 6}, {11, 6},
|
||||
{11, 9}
|
||||
};
|
||||
// Test 5 files
|
||||
int fileCount = 0;
|
||||
for (int i = 0; i < 5; i++) {
|
||||
for (short[] testCase : testSuite) {
|
||||
short replication = testCase[0];
|
||||
short additionalReplication = testCase[1];
|
||||
String src = "/testfile" + (fileCount++);
|
||||
// Create the file with client machine
|
||||
HdfsFileStatus fileStatus = namesystem.startFile(src, perm,
|
||||
clientMachine, clientMachine, EnumSet.of(CreateFlag.CREATE), true,
|
||||
replication, DEFAULT_BLOCK_SIZE, null, false);
|
||||
|
||||
//test chooseTarget for new file
|
||||
LocatedBlock locatedBlock = nameNodeRpc.addBlock(src, clientMachine,
|
||||
null, null, fileStatus.getFileId(), null);
|
||||
doTestLocatedBlock(replication, locatedBlock);
|
||||
|
||||
//test chooseTarget for existing file.
|
||||
LocatedBlock additionalLocatedBlock =
|
||||
nameNodeRpc.getAdditionalDatanode(src, fileStatus.getFileId(),
|
||||
locatedBlock.getBlock(), locatedBlock.getLocations(),
|
||||
locatedBlock.getStorageIDs(), new DatanodeInfo[0],
|
||||
additionalReplication, clientMachine);
|
||||
doTestLocatedBlock(replication + additionalReplication, additionalLocatedBlock);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* Test more randomly. So it covers some special cases.
|
||||
* Like when some racks already have 2 replicas, while some racks have none,
|
||||
* we should choose the racks that have none.
|
||||
*/
|
||||
private void doTestChooseTargetSpecialCase() throws Exception {
|
||||
String clientMachine = "client.foo.com";
|
||||
// Test 5 files
|
||||
String src = "/testfile_1_";
|
||||
// Create the file with client machine
|
||||
HdfsFileStatus fileStatus = namesystem.startFile(src, perm,
|
||||
clientMachine, clientMachine, EnumSet.of(CreateFlag.CREATE), true,
|
||||
(short) 20, DEFAULT_BLOCK_SIZE, null, false);
|
||||
|
||||
//test chooseTarget for new file
|
||||
LocatedBlock locatedBlock = nameNodeRpc.addBlock(src, clientMachine,
|
||||
null, null, fileStatus.getFileId(), null);
|
||||
doTestLocatedBlock(20, locatedBlock);
|
||||
|
||||
DatanodeInfo[] locs = locatedBlock.getLocations();
|
||||
String[] storageIDs = locatedBlock.getStorageIDs();
|
||||
|
||||
for (int time = 0; time < 5; time++) {
|
||||
shuffle(locs, storageIDs);
|
||||
for (int i = 1; i < locs.length; i++) {
|
||||
DatanodeInfo[] partLocs = new DatanodeInfo[i];
|
||||
String[] partStorageIDs = new String[i];
|
||||
System.arraycopy(locs, 0, partLocs, 0, i);
|
||||
System.arraycopy(storageIDs, 0, partStorageIDs, 0, i);
|
||||
for (int j = 1; j < 20 - i; j++) {
|
||||
LocatedBlock additionalLocatedBlock =
|
||||
nameNodeRpc.getAdditionalDatanode(src, fileStatus.getFileId(),
|
||||
locatedBlock.getBlock(), partLocs,
|
||||
partStorageIDs, new DatanodeInfo[0],
|
||||
j, clientMachine);
|
||||
doTestLocatedBlock(i + j, additionalLocatedBlock);
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
private void shuffle(DatanodeInfo[] locs, String[] storageIDs) {
|
||||
int length = locs.length;
|
||||
Object[][] pairs = new Object[length][];
|
||||
for (int i = 0; i < length; i++) {
|
||||
pairs[i] = new Object[]{locs[i], storageIDs[i]};
|
||||
}
|
||||
DFSUtil.shuffle(pairs);
|
||||
for (int i = 0; i < length; i++) {
|
||||
locs[i] = (DatanodeInfo) pairs[i][0];
|
||||
storageIDs[i] = (String) pairs[i][1];
|
||||
}
|
||||
}
|
||||
|
||||
private void doTestLocatedBlock(int replication, LocatedBlock locatedBlock) {
|
||||
assertEquals(replication, locatedBlock.getLocations().length);
|
||||
|
||||
HashMap<String, Integer> racksCount = new HashMap<String, Integer>();
|
||||
for (DatanodeInfo node :
|
||||
locatedBlock.getLocations()) {
|
||||
addToRacksCount(node.getNetworkLocation(), racksCount);
|
||||
}
|
||||
|
||||
int minCount = Integer.MAX_VALUE;
|
||||
int maxCount = Integer.MIN_VALUE;
|
||||
for (Integer rackCount : racksCount.values()) {
|
||||
minCount = Math.min(minCount, rackCount);
|
||||
maxCount = Math.max(maxCount, rackCount);
|
||||
}
|
||||
assertTrue(maxCount - minCount <= 1);
|
||||
}
|
||||
|
||||
private void addToRacksCount(String rack, HashMap<String, Integer> racksCount) {
|
||||
Integer count = racksCount.get(rack);
|
||||
if (count == null) {
|
||||
racksCount.put(rack, 1);
|
||||
} else {
|
||||
racksCount.put(rack, count + 1);
|
||||
}
|
||||
}
|
||||
}
|
||||
Loading…
Reference in New Issue