/**
* 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 static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;
import java.util.ArrayList;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.commons.logging.impl.Log4JLogger;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.BlockLocation;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hdfs.DFSConfigKeys;
import org.apache.hadoop.hdfs.DFSTestUtil;
import org.apache.hadoop.hdfs.HdfsConfiguration;
import org.apache.hadoop.hdfs.MiniDFSCluster;
import org.apache.hadoop.hdfs.protocol.DatanodeID;
import org.apache.hadoop.hdfs.protocol.ExtendedBlock;
import org.apache.hadoop.hdfs.server.datanode.DataNode;
import org.apache.hadoop.hdfs.server.namenode.FSNamesystem;
import org.apache.hadoop.hdfs.server.namenode.NameNodeAdapter;
import org.apache.log4j.Level;
import org.junit.Test;
public class TestBlocksWithNotEnoughRacks {
public static final Log LOG = LogFactory.getLog(TestBlocksWithNotEnoughRacks.class);
static {
((Log4JLogger)LogFactory.getLog(FSNamesystem.class)).getLogger().setLevel(Level.ALL);
((Log4JLogger)LOG).getLogger().setLevel(Level.ALL);
}
/*
* Return a configuration object with low timeouts for testing and
* a topology script set (which enables rack awareness).
*/
private Configuration getConf() {
Configuration conf = new HdfsConfiguration();
// Lower the heart beat interval so the NN quickly learns of dead
// or decommissioned DNs and the NN issues replication and invalidation
// commands quickly (as replies to heartbeats)
conf.setLong(DFSConfigKeys.DFS_HEARTBEAT_INTERVAL_KEY, 1L);
// Have the NN ReplicationMonitor compute the replication and
// invalidation commands to send DNs every second.
conf.setInt(DFSConfigKeys.DFS_NAMENODE_REPLICATION_INTERVAL_KEY, 1);
// Have the NN check for pending replications every second so it
// quickly schedules additional replicas as they are identified.
conf.setInt(DFSConfigKeys.DFS_NAMENODE_REPLICATION_PENDING_TIMEOUT_SEC_KEY, 1);
// The DNs report blocks every second.
conf.setLong(DFSConfigKeys.DFS_BLOCKREPORT_INTERVAL_MSEC_KEY, 1000L);
// Indicates we have multiple racks
conf.set(DFSConfigKeys.NET_TOPOLOGY_SCRIPT_FILE_NAME_KEY, "xyz");
return conf;
}
/*
* Creates a block with all datanodes on the same rack, though the block
* is sufficiently replicated. Adds an additional datanode on a new rack.
* The block should be replicated to the new rack.
*/
@Test
public void testSufficientlyReplBlocksUsesNewRack() throws Exception {
Configuration conf = getConf();
final short REPLICATION_FACTOR = 3;
final Path filePath = new Path("/testFile");
// All datanodes are on the same rack
String racks[] = {"/rack1", "/rack1", "/rack1"};
MiniDFSCluster cluster = new MiniDFSCluster.Builder(conf)
.numDataNodes(racks.length).racks(racks).build();
try {
// Create a file with one block with a replication factor of 3
final FileSystem fs = cluster.getFileSystem();
DFSTestUtil.createFile(fs, filePath, 1L, REPLICATION_FACTOR, 1L);
ExtendedBlock b = DFSTestUtil.getFirstBlock(fs, filePath);
DFSTestUtil.waitForReplication(cluster, b, 1, REPLICATION_FACTOR, 1);
// Add a new datanode on a different rack
String newRacks[] = {"/rack2"};
cluster.startDataNodes(conf, 1, true, null, newRacks);
cluster.waitActive();
DFSTestUtil.waitForReplication(cluster, b, 2, REPLICATION_FACTOR, 0);
} finally {
cluster.shutdown();
}
}
/*
* Like the previous test but the block starts with a single replica,
* and therefore unlike the previous test the block does not start
* off needing replicas.
*/
@Test
public void testSufficientlySingleReplBlockUsesNewRack() throws Exception {
Configuration conf = getConf();
short REPLICATION_FACTOR = 1;
final Path filePath = new Path("/testFile");
String racks[] = {"/rack1", "/rack1", "/rack1", "/rack2"};
MiniDFSCluster cluster = new MiniDFSCluster.Builder(conf)
.numDataNodes(racks.length).racks(racks).build();
final FSNamesystem ns = cluster.getNameNode().getNamesystem();
try {
// Create a file with one block with a replication factor of 1
final FileSystem fs = cluster.getFileSystem();
DFSTestUtil.createFile(fs, filePath, 1L, REPLICATION_FACTOR, 1L);
ExtendedBlock b = DFSTestUtil.getFirstBlock(fs, filePath);
DFSTestUtil.waitForReplication(cluster, b, 1, REPLICATION_FACTOR, 0);
REPLICATION_FACTOR = 2;
NameNodeAdapter.setReplication(ns, "/testFile", REPLICATION_FACTOR);
DFSTestUtil.waitForReplication(cluster, b, 2, REPLICATION_FACTOR, 0);
} finally {
cluster.shutdown();
}
}
/*
* Creates a block with all datanodes on the same rack. Add additional
* datanodes on a different rack and increase the replication factor,
* making sure there are enough replicas across racks. If the previous
* test passes this one should too, however this test may pass when
* the previous one fails because the replication code is explicitly
* triggered by setting the replication factor.
*/
@Test
public void testUnderReplicatedUsesNewRacks() throws Exception {
Configuration conf = getConf();
short REPLICATION_FACTOR = 3;
final Path filePath = new Path("/testFile");
// All datanodes are on the same rack
String racks[] = {"/rack1", "/rack1", "/rack1", "/rack1", "/rack1"};
MiniDFSCluster cluster = new MiniDFSCluster.Builder(conf)
.numDataNodes(racks.length).racks(racks).build();
final FSNamesystem ns = cluster.getNameNode().getNamesystem();
try {
// Create a file with one block
final FileSystem fs = cluster.getFileSystem();
DFSTestUtil.createFile(fs, filePath, 1L, REPLICATION_FACTOR, 1L);
ExtendedBlock b = DFSTestUtil.getFirstBlock(fs, filePath);
DFSTestUtil.waitForReplication(cluster, b, 1, REPLICATION_FACTOR, 1);
// Add new datanodes on a different rack and increase the
// replication factor so the block is underreplicated and make
// sure at least one of the hosts on the new rack is used.
String newRacks[] = {"/rack2", "/rack2"};
cluster.startDataNodes(conf, 2, true, null, newRacks);
REPLICATION_FACTOR = 5;
NameNodeAdapter.setReplication(ns, "/testFile", REPLICATION_FACTOR);
DFSTestUtil.waitForReplication(cluster, b, 2, REPLICATION_FACTOR, 0);
} finally {
cluster.shutdown();
}
}
/*
* Test that a block that is re-replicated because one of its replicas
* is found to be corrupt and is re-replicated across racks.
*/
@Test
public void testCorruptBlockRereplicatedAcrossRacks() throws Exception {
Configuration conf = getConf();
short REPLICATION_FACTOR = 2;
int fileLen = 512;
final Path filePath = new Path("/testFile");
// Datanodes are spread across two racks
String racks[] = {"/rack1", "/rack1", "/rack2", "/rack2"};
MiniDFSCluster cluster = new MiniDFSCluster.Builder(conf)
.numDataNodes(racks.length).racks(racks).build();
final FSNamesystem ns = cluster.getNameNode().getNamesystem();
try {
// Create a file with one block with a replication factor of 2
final FileSystem fs = cluster.getFileSystem();
DFSTestUtil.createFile(fs, filePath, fileLen, REPLICATION_FACTOR, 1L);
final String fileContent = DFSTestUtil.readFile(fs, filePath);
ExtendedBlock b = DFSTestUtil.getFirstBlock(fs, filePath);
DFSTestUtil.waitForReplication(cluster, b, 2, REPLICATION_FACTOR, 0);
// Corrupt a replica of the block
int dnToCorrupt = DFSTestUtil.firstDnWithBlock(cluster, b);
assertTrue(MiniDFSCluster.corruptReplica(dnToCorrupt, b));
// Restart the datanode so blocks are re-scanned, and the corrupt
// block is detected.
cluster.restartDataNode(dnToCorrupt);
// Wait for the namenode to notice the corrupt replica
DFSTestUtil.waitCorruptReplicas(fs, ns, filePath, b, 1);
// The rack policy is still respected
DFSTestUtil.waitForReplication(cluster, b, 2, REPLICATION_FACTOR, 0);
// Ensure all replicas are valid (the corrupt replica may not
// have been cleaned up yet).
for (int i = 0; i < racks.length; i++) {
String blockContent = cluster.readBlockOnDataNode(i, b);
if (blockContent != null && i != dnToCorrupt) {
assertEquals("Corrupt replica", fileContent, blockContent);
}
}
} finally {
cluster.shutdown();
}
}
/*
* Reduce the replication factor of a file, making sure that the only
* cross rack replica is not removed when deleting replicas.
*/
@Test
public void testReduceReplFactorRespectsRackPolicy() throws Exception {
Configuration conf = getConf();
short REPLICATION_FACTOR = 3;
final Path filePath = new Path("/testFile");
String racks[] = {"/rack1", "/rack1", "/rack2", "/rack2"};
MiniDFSCluster cluster = new MiniDFSCluster.Builder(conf)
.numDataNodes(racks.length).racks(racks).build();
final FSNamesystem ns = cluster.getNameNode().getNamesystem();
try {
// Create a file with one block
final FileSystem fs = cluster.getFileSystem();
DFSTestUtil.createFile(fs, filePath, 1L, REPLICATION_FACTOR, 1L);
ExtendedBlock b = DFSTestUtil.getFirstBlock(fs, filePath);
DFSTestUtil.waitForReplication(cluster, b, 2, REPLICATION_FACTOR, 0);
// Decrease the replication factor, make sure the deleted replica
// was not the one that lived on the rack with only one replica,
// ie we should still have 2 racks after reducing the repl factor.
REPLICATION_FACTOR = 2;
NameNodeAdapter.setReplication(ns, "/testFile", REPLICATION_FACTOR);
DFSTestUtil.waitForReplication(cluster, b, 2, REPLICATION_FACTOR, 0);
} finally {
cluster.shutdown();
}
}
/*
* Test that when a block is replicated because a replica is lost due
* to host failure the the rack policy is preserved.
*/
@Test
public void testReplDueToNodeFailRespectsRackPolicy() throws Exception {
Configuration conf = getConf();
short REPLICATION_FACTOR = 3;
final Path filePath = new Path("/testFile");
// Last datanode is on a different rack
String racks[] = {"/rack1", "/rack1", "/rack1", "/rack2", "/rack2"};
MiniDFSCluster cluster = new MiniDFSCluster.Builder(conf)
.numDataNodes(racks.length).racks(racks).build();
final FSNamesystem ns = cluster.getNameNode().getNamesystem();
final DatanodeManager dm = ns.getBlockManager().getDatanodeManager();
try {
// Create a file with one block with a replication factor of 2
final FileSystem fs = cluster.getFileSystem();
DFSTestUtil.createFile(fs, filePath, 1L, REPLICATION_FACTOR, 1L);
ExtendedBlock b = DFSTestUtil.getFirstBlock(fs, filePath);
DFSTestUtil.waitForReplication(cluster, b, 2, REPLICATION_FACTOR, 0);
// Make the last datanode look like it failed to heartbeat by
// calling removeDatanode and stopping it.
ArrayList<DataNode> datanodes = cluster.getDataNodes();
int idx = datanodes.size() - 1;
DataNode dataNode = datanodes.get(idx);
DatanodeID dnId = dataNode.getDatanodeId();
cluster.stopDataNode(idx);
dm.removeDatanode(dnId);
// The block should still have sufficient # replicas, across racks.
// The last node may not have contained a replica, but if it did
// it should have been replicated within the same rack.
DFSTestUtil.waitForReplication(cluster, b, 2, REPLICATION_FACTOR, 0);
// Fail the last datanode again, it's also on rack2 so there is
// only 1 rack for all the replicas
datanodes = cluster.getDataNodes();
idx = datanodes.size() - 1;
dataNode = datanodes.get(idx);
dnId = dataNode.getDatanodeId();
cluster.stopDataNode(idx);
dm.removeDatanode(dnId);
// Make sure we have enough live replicas even though we are
// short one rack and therefore need one replica
DFSTestUtil.waitForReplication(cluster, b, 1, REPLICATION_FACTOR, 1);
} finally {
cluster.shutdown();
}
}
/*
* Test that when the excess replicas of a block are reduced due to
* a node re-joining the cluster the rack policy is not violated.
*/
@Test
public void testReduceReplFactorDueToRejoinRespectsRackPolicy()
throws Exception {
Configuration conf = getConf();
short REPLICATION_FACTOR = 2;
final Path filePath = new Path("/testFile");
// Last datanode is on a different rack
String racks[] = {"/rack1", "/rack1", "/rack2"};
MiniDFSCluster cluster = new MiniDFSCluster.Builder(conf)
.numDataNodes(racks.length).racks(racks).build();
final FSNamesystem ns = cluster.getNameNode().getNamesystem();
final DatanodeManager dm = ns.getBlockManager().getDatanodeManager();
try {
// Create a file with one block
final FileSystem fs = cluster.getFileSystem();
DFSTestUtil.createFile(fs, filePath, 1L, REPLICATION_FACTOR, 1L);
ExtendedBlock b = DFSTestUtil.getFirstBlock(fs, filePath);
DFSTestUtil.waitForReplication(cluster, b, 2, REPLICATION_FACTOR, 0);
// Make the last (cross rack) datanode look like it failed
// to heartbeat by stopping it and calling removeDatanode.
ArrayList<DataNode> datanodes = cluster.getDataNodes();
assertEquals(3, datanodes.size());
DataNode dataNode = datanodes.get(2);
DatanodeID dnId = dataNode.getDatanodeId();
cluster.stopDataNode(2);
dm.removeDatanode(dnId);
// The block gets re-replicated to another datanode so it has a
// sufficient # replicas, but not across racks, so there should
// be 1 rack, and 1 needed replica (even though there are 2 hosts
// available and only 2 replicas required).
DFSTestUtil.waitForReplication(cluster, b, 1, REPLICATION_FACTOR, 1);
// Start the "failed" datanode, which has a replica so the block is
// now over-replicated and therefore a replica should be removed but
// not on the restarted datanode as that would violate the rack policy.
String rack2[] = {"/rack2"};
cluster.startDataNodes(conf, 1, true, null, rack2);
cluster.waitActive();
// The block now has sufficient # replicas, across racks
DFSTestUtil.waitForReplication(cluster, b, 2, REPLICATION_FACTOR, 0);
} finally {
cluster.shutdown();
}
}
/*
* Test that rack policy is still respected when blocks are replicated
* due to node decommissioning.
*/
@Test
public void testNodeDecomissionRespectsRackPolicy() throws Exception {
Configuration conf = getConf();
short REPLICATION_FACTOR = 2;
final Path filePath = new Path("/testFile");
// Configure an excludes file
FileSystem localFileSys = FileSystem.getLocal(conf);
Path workingDir = localFileSys.getWorkingDirectory();
Path dir = new Path(workingDir, "build/test/data/temp/decommission");
Path excludeFile = new Path(dir, "exclude");
assertTrue(localFileSys.mkdirs(dir));
DFSTestUtil.writeFile(localFileSys, excludeFile, "");
conf.set("dfs.hosts.exclude", excludeFile.toUri().getPath());
// Two blocks and four racks
String racks[] = {"/rack1", "/rack1", "/rack2", "/rack2"};
MiniDFSCluster cluster = new MiniDFSCluster.Builder(conf)
.numDataNodes(racks.length).racks(racks).build();
final FSNamesystem ns = cluster.getNameNode().getNamesystem();
try {
// Create a file with one block
final FileSystem fs = cluster.getFileSystem();
DFSTestUtil.createFile(fs, filePath, 1L, REPLICATION_FACTOR, 1L);
ExtendedBlock b = DFSTestUtil.getFirstBlock(fs, filePath);
DFSTestUtil.waitForReplication(cluster, b, 2, REPLICATION_FACTOR, 0);
// Decommission one of the hosts with the block, this should cause
// the block to get replicated to another host on the same rack,
// otherwise the rack policy is violated.
BlockLocation locs[] = fs.getFileBlockLocations(
fs.getFileStatus(filePath), 0, Long.MAX_VALUE);
String name = locs[0].getNames()[0];
DFSTestUtil.writeFile(localFileSys, excludeFile, name);
ns.getBlockManager().getDatanodeManager().refreshNodes(conf);
DFSTestUtil.waitForDecommission(fs, name);
// Check the block still has sufficient # replicas across racks
DFSTestUtil.waitForReplication(cluster, b, 2, REPLICATION_FACTOR, 0);
} finally {
cluster.shutdown();
}
}
/*
* Test that rack policy is still respected when blocks are replicated
* due to node decommissioning, when the blocks are over-replicated.
*/
@Test
public void testNodeDecomissionWithOverreplicationRespectsRackPolicy()
throws Exception {
Configuration conf = getConf();
short REPLICATION_FACTOR = 5;
final Path filePath = new Path("/testFile");
// Configure an excludes file
FileSystem localFileSys = FileSystem.getLocal(conf);
Path workingDir = localFileSys.getWorkingDirectory();
Path dir = new Path(workingDir, "build/test/data/temp/decommission");
Path excludeFile = new Path(dir, "exclude");
assertTrue(localFileSys.mkdirs(dir));
DFSTestUtil.writeFile(localFileSys, excludeFile, "");
conf.set("dfs.hosts.exclude", excludeFile.toUri().getPath());
// All hosts are on two racks, only one host on /rack2
String racks[] = {"/rack1", "/rack2", "/rack1", "/rack1", "/rack1"};
MiniDFSCluster cluster = new MiniDFSCluster.Builder(conf)
.numDataNodes(racks.length).racks(racks).build();
final FSNamesystem ns = cluster.getNameNode().getNamesystem();
try {
final FileSystem fs = cluster.getFileSystem();
DFSTestUtil.createFile(fs, filePath, 1L, REPLICATION_FACTOR, 1L);
ExtendedBlock b = DFSTestUtil.getFirstBlock(fs, filePath);
DFSTestUtil.waitForReplication(cluster, b, 2, REPLICATION_FACTOR, 0);
// Lower the replication factor so the blocks are over replicated
REPLICATION_FACTOR = 2;
fs.setReplication(filePath, REPLICATION_FACTOR);
// Decommission one of the hosts with the block that is not on
// the lone host on rack2 (if we decomission that host it would
// be impossible to respect the rack policy).
BlockLocation locs[] = fs.getFileBlockLocations(
fs.getFileStatus(filePath), 0, Long.MAX_VALUE);
for (String top : locs[0].getTopologyPaths()) {
if (!top.startsWith("/rack2")) {
String name = top.substring("/rack1".length()+1);
DFSTestUtil.writeFile(localFileSys, excludeFile, name);
ns.getBlockManager().getDatanodeManager().refreshNodes(conf);
DFSTestUtil.waitForDecommission(fs, name);
break;
}
}
// Check the block still has sufficient # replicas across racks,
// ie we didn't remove the replica on the host on /rack1.
DFSTestUtil.waitForReplication(cluster, b, 2, REPLICATION_FACTOR, 0);
} finally {
cluster.shutdown();
}
}
}