HDFS-16413. Reconfig dfs usage parameters for datanode (#3863) (#4125)

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litao 2022-03-31 18:24:05 +08:00 committed by GitHub
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10 changed files with 211 additions and 5 deletions

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@ -19,6 +19,7 @@ package org.apache.hadoop.fs;
import org.apache.hadoop.classification.InterfaceAudience; import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability; import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.classification.VisibleForTesting;
import org.slf4j.Logger; import org.slf4j.Logger;
import org.slf4j.LoggerFactory; import org.slf4j.LoggerFactory;
@ -154,10 +155,20 @@ public abstract class CachingGetSpaceUsed implements Closeable, GetSpaceUsed {
/** /**
* How long in between runs of the background refresh. * How long in between runs of the background refresh.
*/ */
long getRefreshInterval() { @VisibleForTesting
public long getRefreshInterval() {
return refreshInterval; return refreshInterval;
} }
/**
* Randomize the refresh interval timing by this amount, the actual interval will be chosen
* uniformly between {@code interval-jitter} and {@code interval+jitter}.
*/
@VisibleForTesting
public long getJitter() {
return jitter;
}
/** /**
* Reset the current used data amount. This should be called * Reset the current used data amount. This should be called
* when the cached value is re-computed. * when the cached value is re-computed.

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@ -20,6 +20,10 @@ package org.apache.hadoop.hdfs.server.datanode;
import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_BLOCKREPORT_INITIAL_DELAY_DEFAULT; import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_BLOCKREPORT_INITIAL_DELAY_DEFAULT;
import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_BLOCKREPORT_INITIAL_DELAY_KEY; import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_BLOCKREPORT_INITIAL_DELAY_KEY;
import static org.apache.hadoop.fs.CommonConfigurationKeysPublic.FS_DU_INTERVAL_DEFAULT;
import static org.apache.hadoop.fs.CommonConfigurationKeysPublic.FS_DU_INTERVAL_KEY;
import static org.apache.hadoop.fs.CommonConfigurationKeysPublic.FS_GETSPACEUSED_JITTER_DEFAULT;
import static org.apache.hadoop.fs.CommonConfigurationKeysPublic.FS_GETSPACEUSED_JITTER_KEY;
import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_BLOCKREPORT_INTERVAL_MSEC_KEY; import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_BLOCKREPORT_INTERVAL_MSEC_KEY;
import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_BLOCKREPORT_INTERVAL_MSEC_DEFAULT; import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_BLOCKREPORT_INTERVAL_MSEC_DEFAULT;
import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_CACHEREPORT_INTERVAL_MSEC_DEFAULT; import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_CACHEREPORT_INTERVAL_MSEC_DEFAULT;
@ -144,6 +148,8 @@ import org.apache.hadoop.hdfs.HDFSPolicyProvider;
import org.apache.hadoop.hdfs.HdfsConfiguration; import org.apache.hadoop.hdfs.HdfsConfiguration;
import org.apache.hadoop.hdfs.server.datanode.checker.DatasetVolumeChecker; import org.apache.hadoop.hdfs.server.datanode.checker.DatasetVolumeChecker;
import org.apache.hadoop.hdfs.server.datanode.checker.StorageLocationChecker; import org.apache.hadoop.hdfs.server.datanode.checker.StorageLocationChecker;
import org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.BlockPoolSlice;
import org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.FsVolumeImpl;
import org.apache.hadoop.hdfs.util.DataTransferThrottler; import org.apache.hadoop.hdfs.util.DataTransferThrottler;
import org.apache.hadoop.util.AutoCloseableLock; import org.apache.hadoop.util.AutoCloseableLock;
import org.apache.hadoop.hdfs.client.BlockReportOptions; import org.apache.hadoop.hdfs.client.BlockReportOptions;
@ -344,7 +350,9 @@ public class DataNode extends ReconfigurableBase
DFS_DATANODE_FILEIO_PROFILING_SAMPLING_PERCENTAGE_KEY, DFS_DATANODE_FILEIO_PROFILING_SAMPLING_PERCENTAGE_KEY,
DFS_DATANODE_OUTLIERS_REPORT_INTERVAL_KEY, DFS_DATANODE_OUTLIERS_REPORT_INTERVAL_KEY,
DFS_DATANODE_MIN_OUTLIER_DETECTION_DISKS_KEY, DFS_DATANODE_MIN_OUTLIER_DETECTION_DISKS_KEY,
DFS_DATANODE_SLOWDISK_LOW_THRESHOLD_MS_KEY)); DFS_DATANODE_SLOWDISK_LOW_THRESHOLD_MS_KEY,
FS_DU_INTERVAL_KEY,
FS_GETSPACEUSED_JITTER_KEY));
public static final Log METRICS_LOG = LogFactory.getLog("DataNodeMetricsLog"); public static final Log METRICS_LOG = LogFactory.getLog("DataNodeMetricsLog");
@ -668,6 +676,9 @@ public class DataNode extends ReconfigurableBase
case DFS_DATANODE_MIN_OUTLIER_DETECTION_DISKS_KEY: case DFS_DATANODE_MIN_OUTLIER_DETECTION_DISKS_KEY:
case DFS_DATANODE_SLOWDISK_LOW_THRESHOLD_MS_KEY: case DFS_DATANODE_SLOWDISK_LOW_THRESHOLD_MS_KEY:
return reconfSlowDiskParameters(property, newVal); return reconfSlowDiskParameters(property, newVal);
case FS_DU_INTERVAL_KEY:
case FS_GETSPACEUSED_JITTER_KEY:
return reconfDfsUsageParameters(property, newVal);
default: default:
break; break;
} }
@ -849,6 +860,43 @@ public class DataNode extends ReconfigurableBase
} }
} }
private String reconfDfsUsageParameters(String property, String newVal)
throws ReconfigurationException {
String result = null;
try {
LOG.info("Reconfiguring {} to {}", property, newVal);
if (property.equals(FS_DU_INTERVAL_KEY)) {
Preconditions.checkNotNull(data, "FsDatasetSpi has not been initialized.");
long interval = (newVal == null ? FS_DU_INTERVAL_DEFAULT :
Long.parseLong(newVal));
result = Long.toString(interval);
List<FsVolumeImpl> volumeList = data.getVolumeList();
for (FsVolumeImpl fsVolume : volumeList) {
Map<String, BlockPoolSlice> blockPoolSlices = fsVolume.getBlockPoolSlices();
for (BlockPoolSlice value : blockPoolSlices.values()) {
value.updateDfsUsageConfig(interval, null);
}
}
} else if (property.equals(FS_GETSPACEUSED_JITTER_KEY)) {
Preconditions.checkNotNull(data, "FsDatasetSpi has not been initialized.");
long jitter = (newVal == null ? FS_GETSPACEUSED_JITTER_DEFAULT :
Long.parseLong(newVal));
result = Long.toString(jitter);
List<FsVolumeImpl> volumeList = data.getVolumeList();
for (FsVolumeImpl fsVolume : volumeList) {
Map<String, BlockPoolSlice> blockPoolSlices = fsVolume.getBlockPoolSlices();
for (BlockPoolSlice value : blockPoolSlices.values()) {
value.updateDfsUsageConfig(null, jitter);
}
}
}
LOG.info("RECONFIGURE* changed {} to {}", property, newVal);
return result;
} catch (IllegalArgumentException | IOException e) {
throw new ReconfigurationException(property, newVal, getConf().get(property), e);
}
}
/** /**
* Get a list of the keys of the re-configurable properties in configuration. * Get a list of the keys of the re-configurable properties in configuration.
*/ */

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@ -36,6 +36,7 @@ import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.StorageType; import org.apache.hadoop.fs.StorageType;
import org.apache.hadoop.util.AutoCloseableLock; import org.apache.hadoop.util.AutoCloseableLock;
import org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.FsVolumeImpl;
import org.apache.hadoop.hdfs.DFSConfigKeys; import org.apache.hadoop.hdfs.DFSConfigKeys;
import org.apache.hadoop.hdfs.protocol.Block; import org.apache.hadoop.hdfs.protocol.Block;
import org.apache.hadoop.hdfs.protocol.BlockListAsLongs; import org.apache.hadoop.hdfs.protocol.BlockListAsLongs;
@ -679,4 +680,9 @@ public interface FsDatasetSpi<V extends FsVolumeSpi> extends FSDatasetMBean {
* @throws IOException * @throws IOException
*/ */
Set<? extends Replica> deepCopyReplica(String bpid) throws IOException; Set<? extends Replica> deepCopyReplica(String bpid) throws IOException;
/**
* Get the volume list.
*/
List<FsVolumeImpl> getVolumeList();
} }

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@ -47,6 +47,7 @@ import java.util.concurrent.locks.ReentrantReadWriteLock;
import java.util.concurrent.TimeUnit; import java.util.concurrent.TimeUnit;
import org.apache.hadoop.hdfs.server.datanode.FSCachingGetSpaceUsed; import org.apache.hadoop.hdfs.server.datanode.FSCachingGetSpaceUsed;
import org.apache.hadoop.util.Preconditions;
import org.slf4j.Logger; import org.slf4j.Logger;
import org.slf4j.LoggerFactory; import org.slf4j.LoggerFactory;
import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.conf.Configuration;
@ -78,6 +79,9 @@ import org.apache.hadoop.util.Timer;
import org.apache.hadoop.thirdparty.com.google.common.annotations.VisibleForTesting; import org.apache.hadoop.thirdparty.com.google.common.annotations.VisibleForTesting;
import static org.apache.hadoop.fs.CommonConfigurationKeysPublic.FS_DU_INTERVAL_KEY;
import static org.apache.hadoop.fs.CommonConfigurationKeysPublic.FS_GETSPACEUSED_JITTER_KEY;
/** /**
* A block pool slice represents a portion of a block pool stored on a volume. * A block pool slice represents a portion of a block pool stored on a volume.
* Taken together, all BlockPoolSlices sharing a block pool ID across a * Taken together, all BlockPoolSlices sharing a block pool ID across a
@ -85,7 +89,7 @@ import org.apache.hadoop.thirdparty.com.google.common.annotations.VisibleForTest
* *
* This class is synchronized by {@link FsVolumeImpl}. * This class is synchronized by {@link FsVolumeImpl}.
*/ */
class BlockPoolSlice { public class BlockPoolSlice {
static final Logger LOG = LoggerFactory.getLogger(BlockPoolSlice.class); static final Logger LOG = LoggerFactory.getLogger(BlockPoolSlice.class);
private final String bpid; private final String bpid;
@ -111,6 +115,8 @@ class BlockPoolSlice {
private final Timer timer; private final Timer timer;
private final int maxDataLength; private final int maxDataLength;
private final FileIoProvider fileIoProvider; private final FileIoProvider fileIoProvider;
private final Configuration config;
private final File bpDir;
private static ForkJoinPool addReplicaThreadPool = null; private static ForkJoinPool addReplicaThreadPool = null;
private static final int VOLUMES_REPLICA_ADD_THREADPOOL_SIZE = Runtime private static final int VOLUMES_REPLICA_ADD_THREADPOOL_SIZE = Runtime
@ -124,7 +130,7 @@ class BlockPoolSlice {
}; };
// TODO:FEDERATION scalability issue - a thread per DU is needed // TODO:FEDERATION scalability issue - a thread per DU is needed
private final GetSpaceUsed dfsUsage; private volatile GetSpaceUsed dfsUsage;
/** /**
* Create a blook pool slice * Create a blook pool slice
@ -137,6 +143,8 @@ class BlockPoolSlice {
*/ */
BlockPoolSlice(String bpid, FsVolumeImpl volume, File bpDir, BlockPoolSlice(String bpid, FsVolumeImpl volume, File bpDir,
Configuration conf, Timer timer) throws IOException { Configuration conf, Timer timer) throws IOException {
this.config = conf;
this.bpDir = bpDir;
this.bpid = bpid; this.bpid = bpid;
this.volume = volume; this.volume = volume;
this.fileIoProvider = volume.getFileIoProvider(); this.fileIoProvider = volume.getFileIoProvider();
@ -228,6 +236,35 @@ class BlockPoolSlice {
SHUTDOWN_HOOK_PRIORITY); SHUTDOWN_HOOK_PRIORITY);
} }
public void updateDfsUsageConfig(Long interval, Long jitter) throws IOException {
// Close the old dfsUsage if it is CachingGetSpaceUsed.
if (dfsUsage instanceof CachingGetSpaceUsed) {
((CachingGetSpaceUsed) dfsUsage).close();
}
if (interval != null) {
Preconditions.checkArgument(interval > 0,
FS_DU_INTERVAL_KEY + " should be larger than 0");
config.setLong(FS_DU_INTERVAL_KEY, interval);
}
if (jitter != null) {
Preconditions.checkArgument(jitter >= 0,
FS_GETSPACEUSED_JITTER_KEY + " should be larger than or equal to 0");
config.setLong(FS_GETSPACEUSED_JITTER_KEY, jitter);
}
// Start new dfsUsage.
this.dfsUsage = new FSCachingGetSpaceUsed.Builder().setBpid(bpid)
.setVolume(volume)
.setPath(bpDir)
.setConf(config)
.setInitialUsed(loadDfsUsed())
.build();
}
@VisibleForTesting
public GetSpaceUsed getDfsUsage() {
return dfsUsage;
}
private synchronized static void initializeAddReplicaPool(Configuration conf, private synchronized static void initializeAddReplicaPool(Configuration conf,
FsDatasetImpl dataset) { FsDatasetImpl dataset) {
if (addReplicaThreadPool == null) { if (addReplicaThreadPool == null) {

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@ -3431,5 +3431,10 @@ class FsDatasetImpl implements FsDatasetSpi<FsVolumeImpl> {
} }
} }
} }
@Override
public List<FsVolumeImpl> getVolumeList() {
return volumes.getVolumes();
}
} }

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@ -493,6 +493,10 @@ public class FsVolumeImpl implements FsVolumeSpi {
return recentReserved; return recentReserved;
} }
public Map<String, BlockPoolSlice> getBlockPoolSlices() {
return bpSlices;
}
long getReserved(){ long getReserved(){
return reserved != null ? reserved.getReserved() : 0; return reserved != null ? reserved.getReserved() : 0;
} }

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@ -40,6 +40,7 @@ import javax.management.NotCompliantMBeanException;
import javax.management.ObjectName; import javax.management.ObjectName;
import javax.management.StandardMBean; import javax.management.StandardMBean;
import org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.FsVolumeImpl;
import org.apache.hadoop.thirdparty.com.google.common.math.LongMath; import org.apache.hadoop.thirdparty.com.google.common.math.LongMath;
import org.apache.commons.lang3.ArrayUtils; import org.apache.commons.lang3.ArrayUtils;
import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.conf.Configuration;
@ -1595,5 +1596,10 @@ public class SimulatedFSDataset implements FsDatasetSpi<FsVolumeSpi> {
} }
return Collections.unmodifiableSet(replicas); return Collections.unmodifiableSet(replicas);
} }
@Override
public List<FsVolumeImpl> getVolumeList() {
return null;
}
} }

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@ -19,6 +19,10 @@
package org.apache.hadoop.hdfs.server.datanode; package org.apache.hadoop.hdfs.server.datanode;
import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_BLOCKREPORT_INITIAL_DELAY_KEY; import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_BLOCKREPORT_INITIAL_DELAY_KEY;
import static org.apache.hadoop.fs.CommonConfigurationKeysPublic.FS_DU_INTERVAL_DEFAULT;
import static org.apache.hadoop.fs.CommonConfigurationKeysPublic.FS_DU_INTERVAL_KEY;
import static org.apache.hadoop.fs.CommonConfigurationKeysPublic.FS_GETSPACEUSED_JITTER_DEFAULT;
import static org.apache.hadoop.fs.CommonConfigurationKeysPublic.FS_GETSPACEUSED_JITTER_KEY;
import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_BLOCKREPORT_INTERVAL_MSEC_DEFAULT; import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_BLOCKREPORT_INTERVAL_MSEC_DEFAULT;
import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_BLOCKREPORT_INTERVAL_MSEC_KEY; import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_BLOCKREPORT_INTERVAL_MSEC_KEY;
import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_BLOCKREPORT_SPLIT_THRESHOLD_KEY; import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_BLOCKREPORT_SPLIT_THRESHOLD_KEY;
@ -49,15 +53,21 @@ import static org.junit.Assert.fail;
import java.io.File; import java.io.File;
import java.io.IOException; import java.io.IOException;
import java.net.InetSocketAddress; import java.net.InetSocketAddress;
import java.util.List;
import java.util.Map;
import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.conf.ReconfigurationException; import org.apache.hadoop.conf.ReconfigurationException;
import org.apache.hadoop.fs.CachingGetSpaceUsed;
import org.apache.hadoop.fs.CommonConfigurationKeys; import org.apache.hadoop.fs.CommonConfigurationKeys;
import org.apache.hadoop.fs.FileUtil; import org.apache.hadoop.fs.FileUtil;
import org.apache.hadoop.fs.GetSpaceUsed;
import org.apache.hadoop.hdfs.DFSConfigKeys; import org.apache.hadoop.hdfs.DFSConfigKeys;
import org.apache.hadoop.hdfs.HdfsConfiguration; import org.apache.hadoop.hdfs.HdfsConfiguration;
import org.apache.hadoop.hdfs.MiniDFSCluster; import org.apache.hadoop.hdfs.MiniDFSCluster;
import org.apache.hadoop.hdfs.MiniDFSNNTopology; import org.apache.hadoop.hdfs.MiniDFSNNTopology;
import org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.BlockPoolSlice;
import org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.FsVolumeImpl;
import org.apache.hadoop.test.LambdaTestUtils; import org.apache.hadoop.test.LambdaTestUtils;
import org.junit.After; import org.junit.After;
import org.junit.Assert; import org.junit.Assert;
@ -673,4 +683,77 @@ public class TestDataNodeReconfiguration {
dn.getDiskMetrics().getSlowDiskDetector().getLowThresholdMs()); dn.getDiskMetrics().getSlowDiskDetector().getLowThresholdMs());
} }
} }
@Test
public void testDfsUsageParameters() throws ReconfigurationException {
String[] dfsUsageParameters = {
FS_DU_INTERVAL_KEY,
FS_GETSPACEUSED_JITTER_KEY};
for (int i = 0; i < NUM_DATA_NODE; i++) {
DataNode dn = cluster.getDataNodes().get(i);
// Try invalid values.
for (String parameter : dfsUsageParameters) {
try {
dn.reconfigureProperty(parameter, "text");
fail("ReconfigurationException expected");
} catch (ReconfigurationException expected) {
assertTrue("expecting NumberFormatException",
expected.getCause() instanceof NumberFormatException);
}
try {
dn.reconfigureProperty(parameter, String.valueOf(-1));
fail("ReconfigurationException expected");
} catch (ReconfigurationException expected) {
assertTrue("expecting IllegalArgumentException",
expected.getCause() instanceof IllegalArgumentException);
}
}
// Change and verify properties.
for (String parameter : dfsUsageParameters) {
dn.reconfigureProperty(parameter, "99");
}
List<FsVolumeImpl> volumeList = dn.data.getVolumeList();
for (FsVolumeImpl fsVolume : volumeList) {
Map<String, BlockPoolSlice> blockPoolSlices = fsVolume.getBlockPoolSlices();
for (Map.Entry<String, BlockPoolSlice> entry : blockPoolSlices.entrySet()) {
GetSpaceUsed dfsUsage = entry.getValue().getDfsUsage();
if (dfsUsage instanceof CachingGetSpaceUsed) {
assertEquals(99,
((CachingGetSpaceUsed) entry.getValue().getDfsUsage()).getRefreshInterval());
assertEquals(99,
((CachingGetSpaceUsed) entry.getValue().getDfsUsage()).getJitter());
}
}
}
// Revert to default and verify.
for (String parameter : dfsUsageParameters) {
dn.reconfigureProperty(parameter, null);
}
for (FsVolumeImpl fsVolume : volumeList) {
Map<String, BlockPoolSlice> blockPoolSlices = fsVolume.getBlockPoolSlices();
for (Map.Entry<String, BlockPoolSlice> entry : blockPoolSlices.entrySet()) {
GetSpaceUsed dfsUsage = entry.getValue().getDfsUsage();
if (dfsUsage instanceof CachingGetSpaceUsed) {
assertEquals(String.format("expect %s is not configured",
FS_DU_INTERVAL_KEY), FS_DU_INTERVAL_DEFAULT,
((CachingGetSpaceUsed) entry.getValue().getDfsUsage()).getRefreshInterval());
assertEquals(String.format("expect %s is not configured",
FS_GETSPACEUSED_JITTER_KEY), FS_GETSPACEUSED_JITTER_DEFAULT,
((CachingGetSpaceUsed) entry.getValue().getDfsUsage()).getJitter());
}
assertEquals(String.format("expect %s is not configured",
FS_DU_INTERVAL_KEY), null,
dn.getConf().get(FS_DU_INTERVAL_KEY));
assertEquals(String.format("expect %s is not configured",
FS_GETSPACEUSED_JITTER_KEY), null,
dn.getConf().get(FS_GETSPACEUSED_JITTER_KEY));
}
}
}
}
} }

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@ -24,6 +24,7 @@ import java.util.*;
import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.StorageType; import org.apache.hadoop.fs.StorageType;
import org.apache.hadoop.util.AutoCloseableLock; import org.apache.hadoop.util.AutoCloseableLock;
import org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.FsVolumeImpl;
import org.apache.hadoop.hdfs.protocol.Block; import org.apache.hadoop.hdfs.protocol.Block;
import org.apache.hadoop.hdfs.protocol.BlockListAsLongs; import org.apache.hadoop.hdfs.protocol.BlockListAsLongs;
import org.apache.hadoop.hdfs.protocol.BlockLocalPathInfo; import org.apache.hadoop.hdfs.protocol.BlockLocalPathInfo;
@ -465,4 +466,9 @@ public class ExternalDatasetImpl implements FsDatasetSpi<ExternalVolumeImpl> {
throws IOException { throws IOException {
return Collections.EMPTY_SET; return Collections.EMPTY_SET;
} }
@Override
public List<FsVolumeImpl> getVolumeList() {
return null;
}
} }

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@ -331,7 +331,7 @@ public class TestDFSAdmin {
final List<String> outs = Lists.newArrayList(); final List<String> outs = Lists.newArrayList();
final List<String> errs = Lists.newArrayList(); final List<String> errs = Lists.newArrayList();
getReconfigurableProperties("datanode", address, outs, errs); getReconfigurableProperties("datanode", address, outs, errs);
assertEquals(16, outs.size()); assertEquals(18, outs.size());
assertEquals(DFSConfigKeys.DFS_DATANODE_DATA_DIR_KEY, outs.get(1)); assertEquals(DFSConfigKeys.DFS_DATANODE_DATA_DIR_KEY, outs.get(1));
} }