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HDFS-13608. [SBN read] Edit Tail Fast Path Part 2: Add ability for JournalNode to serve edits via RPC. Contributed by Erik Krogen.

This commit is contained in:
Erik Krogen 2018-05-23 12:42:13 -07:00 committed by Chen Liang
parent c40ddf9b5b
commit abb8614dcf
9 changed files with 212 additions and 2 deletions
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5
hadoop-common-project/hadoop-common/src/site/markdown/Metrics.md
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@ -321,6 +321,11 @@ The server-side metrics for a journal from the JournalNode's perspective. Each m
| `LastWrittenTxId` | The highest transaction id stored on this JournalNode |
| `LastPromisedEpoch` | The last epoch number which this node has promised not to accept any lower epoch, or 0 if no promises have been made |
| `LastJournalTimestamp` | The timestamp of last successfully written transaction |
| `TxnsServedViaRpc` | Number of transactions served via the RPC mechanism |
| `BytesServedViaRpc` | Number of bytes served via the RPC mechanism |
| `RpcRequestCacheMissAmountNumMisses` | Number of RPC requests which could not be served due to lack of data in the cache |
| `RpcRequestCacheMissAmountAvgTxns` | The average number of transactions by which a request missed the cache; for example if transaction ID 10 is requested and the cache's oldest transaction is ID 15, value 5 will be added to this average |
| `RpcEmptyResponses` | Number of RPC requests with zero edits returned |
datanode
--------

22
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/qjournal/protocol/QJournalProtocol.java
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@ -24,6 +24,7 @@ import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.hdfs.DFSConfigKeys;
import org.apache.hadoop.hdfs.qjournal.client.QuorumJournalManager;
import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.GetEditLogManifestResponseProto;
import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.GetJournaledEditsResponseProto;
import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.GetJournalStateResponseProto;
import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.NewEpochResponseProto;
import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.PrepareRecoveryResponseProto;
@ -140,6 +141,27 @@ public interface QJournalProtocol {
boolean inProgressOk)
throws IOException;
/**
* Fetch edit logs present in the Journal's in-memory cache of edits
* ({@link org.apache.hadoop.hdfs.qjournal.server.JournaledEditsCache}).
* To enable this cache, in-progress edit log tailing must be enabled via the
* {@value DFSConfigKeys#DFS_HA_TAILEDITS_INPROGRESS_KEY} configuration key.
*
* @param jid The ID of the journal from which to fetch edits.
* @param nameServiceId The ID of the namespace for which to fetch edits.
* @param sinceTxId Fetch edits starting at this transaction ID
* @param maxTxns Request at most this many transactions to be returned
* @throws IOException If there was an issue encountered while fetching edits
* from the cache, including a cache miss (cache does not contain the
* requested edits). The caller should then attempt to fetch the edits via
* the streaming mechanism (starting with
* {@link #getEditLogManifest(String, String, long, boolean)}).
* @return Response containing serialized edits to be loaded
* @see org.apache.hadoop.hdfs.qjournal.server.JournaledEditsCache
*/
GetJournaledEditsResponseProto getJournaledEdits(String jid,
String nameServiceId, long sinceTxId, int maxTxns) throws IOException;
/**
* Begin the recovery process for a given segment. See the HDFS-3077
* design document for details.

14
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/qjournal/protocolPB/QJournalProtocolServerSideTranslatorPB.java
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@ -45,6 +45,8 @@ import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.FormatReq
import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.FormatResponseProto;
import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.GetEditLogManifestRequestProto;
import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.GetEditLogManifestResponseProto;
import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.GetJournaledEditsRequestProto;
import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.GetJournaledEditsResponseProto;
import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.GetJournalCTimeRequestProto;
import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.GetJournalCTimeResponseProto;
import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.GetJournalStateRequestProto;
@ -235,6 +237,18 @@ public class QJournalProtocolServerSideTranslatorPB implements QJournalProtocolP
}
}
@Override
public GetJournaledEditsResponseProto getJournaledEdits(
RpcController controller, GetJournaledEditsRequestProto request)
throws ServiceException {
try {
return impl.getJournaledEdits(request.getJid().getIdentifier(),
request.hasNameServiceId() ? request.getNameServiceId() : null,
request.getSinceTxId(), request.getMaxTxns());
} catch (IOException ioe) {
throw new ServiceException(ioe);
}
}
@Override
public PrepareRecoveryResponseProto prepareRecovery(RpcController controller,

20
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/qjournal/protocolPB/QJournalProtocolTranslatorPB.java
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@ -40,6 +40,8 @@ import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.FinalizeL
import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.FormatRequestProto;
import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.GetEditLogManifestRequestProto;
import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.GetEditLogManifestResponseProto;
import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.GetJournaledEditsRequestProto;
import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.GetJournaledEditsResponseProto;
import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.GetJournalCTimeRequestProto;
import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.GetJournalCTimeResponseProto;
import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.GetJournalStateRequestProto;
@ -281,6 +283,24 @@ public class QJournalProtocolTranslatorPB implements ProtocolMetaInterface,
}
}
@Override
public GetJournaledEditsResponseProto getJournaledEdits(String jid,
String nameServiceId, long sinceTxId, int maxTxns) throws IOException {
try {
GetJournaledEditsRequestProto.Builder req =
GetJournaledEditsRequestProto.newBuilder()
.setJid(convertJournalId(jid))
.setSinceTxId(sinceTxId)
.setMaxTxns(maxTxns);
if (nameServiceId != null) {
req.setNameServiceId(nameServiceId);
}
return rpcProxy.getJournaledEdits(NULL_CONTROLLER, req.build());
} catch (ServiceException se) {
throw ProtobufHelper.getRemoteException(se);
}
}
@Override
public PrepareRecoveryResponseProto prepareRecovery(RequestInfo reqInfo,
long segmentTxId) throws IOException {

59
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/qjournal/server/Journal.java
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@ -17,6 +17,7 @@
*/
package org.apache.hadoop.hdfs.qjournal.server;
import com.google.protobuf.ByteString;
import java.io.Closeable;
import java.io.File;
import java.io.FileInputStream;
@ -24,9 +25,11 @@ import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStreamWriter;
import java.net.URL;
import java.nio.ByteBuffer;
import java.nio.file.Files;
import java.nio.file.StandardCopyOption;
import java.security.PrivilegedExceptionAction;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.concurrent.TimeUnit;
@ -36,10 +39,12 @@ import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileUtil;
import org.apache.hadoop.hdfs.DFSConfigKeys;
import org.apache.hadoop.hdfs.qjournal.protocol.JournalNotFormattedException;
import org.apache.hadoop.hdfs.qjournal.protocol.JournalOutOfSyncException;
import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocol;
import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos;
import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.GetJournaledEditsResponseProto;
import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.NewEpochResponseProto;
import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.PersistedRecoveryPaxosData;
import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.PrepareRecoveryResponseProto;
@ -85,6 +90,7 @@ public class Journal implements Closeable {
// Current writing state
private EditLogOutputStream curSegment;
private long curSegmentTxId = HdfsServerConstants.INVALID_TXID;
private int curSegmentLayoutVersion = 0;
private long nextTxId = HdfsServerConstants.INVALID_TXID;
private long highestWrittenTxId = 0;
@ -133,6 +139,8 @@ public class Journal implements Closeable {
private final FileJournalManager fjm;
private final JournaledEditsCache cache;
private final JournalMetrics metrics;
private long lastJournalTimestamp = 0;
@ -157,6 +165,13 @@ public class Journal implements Closeable {
this.fjm = storage.getJournalManager();
if (conf.getBoolean(DFSConfigKeys.DFS_HA_TAILEDITS_INPROGRESS_KEY,
DFSConfigKeys.DFS_HA_TAILEDITS_INPROGRESS_DEFAULT)) {
this.cache = new JournaledEditsCache(conf);
} else {
this.cache = null;
}
this.metrics = JournalMetrics.create(this);
EditLogFile latest = scanStorageForLatestEdits();
@ -361,6 +376,7 @@ public class Journal implements Closeable {
curSegment.abort();
curSegment = null;
curSegmentTxId = HdfsServerConstants.INVALID_TXID;
curSegmentLayoutVersion = 0;
}
/**
@ -406,6 +422,9 @@ public class Journal implements Closeable {
LOG.trace("Writing txid " + firstTxnId + "-" + lastTxnId +
" ; journal id: " + journalId);
}
if (cache != null) {
cache.storeEdits(records, firstTxnId, lastTxnId, curSegmentLayoutVersion);
}
// If the edit has already been marked as committed, we know
// it has been fsynced on a quorum of other nodes, and we are
@ -593,6 +612,7 @@ public class Journal implements Closeable {
curSegment = fjm.startLogSegment(txid, layoutVersion);
curSegmentTxId = txid;
curSegmentLayoutVersion = layoutVersion;
nextTxId = txid;
}
@ -612,6 +632,7 @@ public class Journal implements Closeable {
curSegment.close();
curSegment = null;
curSegmentTxId = HdfsServerConstants.INVALID_TXID;
curSegmentLayoutVersion = 0;
}
checkSync(nextTxId == endTxId + 1,
@ -712,6 +733,44 @@ public class Journal implements Closeable {
return new RemoteEditLogManifest(logs, getCommittedTxnId());
}
/**
* @see QJournalProtocol#getJournaledEdits(String, String, long, int)
*/
public GetJournaledEditsResponseProto getJournaledEdits(long sinceTxId,
int maxTxns) throws IOException {
if (cache == null) {
throw new IOException("The journal edits cache is not enabled, which " +
"is a requirement to fetch journaled edits via RPC. Please enable " +
"it via " + DFSConfigKeys.DFS_HA_TAILEDITS_INPROGRESS_KEY);
}
if (sinceTxId > getHighestWrittenTxId()) {
// Requested edits that don't exist yet; short-circuit the cache here
metrics.rpcEmptyResponses.incr();
return GetJournaledEditsResponseProto.newBuilder().setTxnCount(0).build();
}
try {
List<ByteBuffer> buffers = new ArrayList<>();
int txnCount = cache.retrieveEdits(sinceTxId, maxTxns, buffers);
int totalSize = 0;
for (ByteBuffer buf : buffers) {
totalSize += buf.remaining();
}
metrics.txnsServedViaRpc.incr(txnCount);
metrics.bytesServedViaRpc.incr(totalSize);
ByteString.Output output = ByteString.newOutput(totalSize);
for (ByteBuffer buf : buffers) {
output.write(buf.array(), buf.position(), buf.remaining());
}
return GetJournaledEditsResponseProto.newBuilder()
.setTxnCount(txnCount)
.setEditLog(output.toByteString())
.build();
} catch (JournaledEditsCache.CacheMissException cme) {
metrics.rpcRequestCacheMissAmount.add(cme.getCacheMissAmount());
throw cme;
}
}
/**
* @return the current state of the given segment, or null if the
* segment does not exist.

18
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/qjournal/server/JournalMetrics.java
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@ -25,6 +25,8 @@ import org.apache.hadoop.metrics2.lib.DefaultMetricsSystem;
import org.apache.hadoop.metrics2.lib.MetricsRegistry;
import org.apache.hadoop.metrics2.lib.MutableCounterLong;
import org.apache.hadoop.metrics2.lib.MutableQuantiles;
import org.apache.hadoop.metrics2.lib.MutableStat;
/**
* The server-side metrics for a journal from the JournalNode's
@ -43,6 +45,22 @@ class JournalMetrics {
@Metric("Number of bytes written since startup")
MutableCounterLong bytesWritten;
@Metric("Number of txns served via RPC")
MutableCounterLong txnsServedViaRpc;
@Metric("Number of bytes served via RPC")
MutableCounterLong bytesServedViaRpc;
@Metric
MutableStat rpcRequestCacheMissAmount = new MutableStat(
"RpcRequestCacheMissAmount", "Number of RPC requests unable to be " +
"served due to lack of availability in cache, and how many " +
"transactions away the request was from being in the cache.",
"Misses", "Txns");
@Metric("Number of RPC requests with zero edits returned")
MutableCounterLong rpcEmptyResponses;
@Metric("Number of batches written where this node was lagging")
MutableCounterLong batchesWrittenWhileLagging;

8
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/qjournal/server/JournalNodeRpcServer.java
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@ -32,6 +32,7 @@ import org.apache.hadoop.hdfs.qjournal.protocol.InterQJournalProtocol;
import org.apache.hadoop.hdfs.qjournal.protocol.InterQJournalProtocolProtos.InterQJournalProtocolService;
import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocol;
import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.GetEditLogManifestResponseProto;
import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.GetJournaledEditsResponseProto;
import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.GetJournalStateResponseProto;
import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.NewEpochResponseProto;
import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.PrepareRecoveryResponseProto;
@ -233,6 +234,13 @@ public class JournalNodeRpcServer implements QJournalProtocol,
.build();
}
@Override
public GetJournaledEditsResponseProto getJournaledEdits(String jid,
String nameServiceId, long sinceTxId, int maxTxns) throws IOException {
return jn.getOrCreateJournal(jid, nameServiceId)
.getJournaledEdits(sinceTxId, maxTxns);
}
@Override
public PrepareRecoveryResponseProto prepareRecovery(RequestInfo reqInfo,
long segmentTxId) throws IOException {

18
hadoop-hdfs-project/hadoop-hdfs/src/main/proto/QJournalProtocol.proto
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@ -284,6 +284,21 @@ message GetEditLogManifestResponseProto {
// required NamespaceInfoProto nsInfo = 2;
}
/**
* getJournaledEdits()
*/
message GetJournaledEditsRequestProto {
required JournalIdProto jid = 1;
required uint64 sinceTxId = 2;
required uint32 maxTxns = 3;
optional string nameServiceId = 4;
}
message GetJournaledEditsResponseProto {
required uint32 txnCount = 1;
optional bytes editLog = 2;
}
/**
* prepareRecovery()
*/
@ -363,6 +378,9 @@ service QJournalProtocolService {
rpc getEditLogManifest(GetEditLogManifestRequestProto)
returns (GetEditLogManifestResponseProto);
rpc getJournaledEdits(GetJournaledEditsRequestProto)
returns (GetJournaledEditsResponseProto);
rpc prepareRecovery(PrepareRecoveryRequestProto)
returns (PrepareRecoveryResponseProto);

46
hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/qjournal/server/TestJournal.java
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@ -17,19 +17,25 @@
*/
package org.apache.hadoop.hdfs.qjournal.server;
import static org.junit.Assert.assertArrayEquals;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;
import static org.junit.Assert.fail;
import com.google.common.primitives.Bytes;
import java.io.ByteArrayOutputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.IOException;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileUtil;
import org.apache.hadoop.hdfs.DFSConfigKeys;
import org.apache.hadoop.hdfs.MiniDFSCluster;
import org.apache.hadoop.hdfs.qjournal.QJMTestUtil;
import org.apache.hadoop.hdfs.qjournal.protocol.JournalOutOfSyncException;
import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.GetJournaledEditsResponseProto;
import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.NewEpochResponseProto;
import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.NewEpochResponseProtoOrBuilder;
import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.SegmentStateProto;
@ -38,6 +44,7 @@ import org.apache.hadoop.hdfs.server.common.HdfsServerConstants.StartupOption;
import org.apache.hadoop.hdfs.server.common.Storage;
import org.apache.hadoop.hdfs.server.common.Storage.StorageDirectory;
import org.apache.hadoop.hdfs.server.common.StorageErrorReporter;
import org.apache.hadoop.hdfs.server.namenode.EditLogFileOutputStream;
import org.apache.hadoop.hdfs.server.namenode.NameNodeLayoutVersion;
import org.apache.hadoop.hdfs.server.protocol.NamespaceInfo;
import org.apache.hadoop.io.IOUtils;
@ -71,6 +78,8 @@ public class TestJournal {
public void setup() throws Exception {
FileUtil.fullyDelete(TEST_LOG_DIR);
conf = new Configuration();
// Enable fetching edits via RPC
conf.setBoolean(DFSConfigKeys.DFS_HA_TAILEDITS_INPROGRESS_KEY, true);
journal = new Journal(conf, TEST_LOG_DIR, JID, StartupOption.REGULAR,
mockErrorReporter);
journal.format(FAKE_NSINFO);
@ -434,4 +443,41 @@ public class TestJournal {
}
}
@Test
public void testReadFromCache() throws Exception {
journal.newEpoch(FAKE_NSINFO, 1);
journal.startLogSegment(makeRI(1), 1,
NameNodeLayoutVersion.CURRENT_LAYOUT_VERSION);
journal.journal(makeRI(2), 1, 1, 5, QJMTestUtil.createTxnData(1, 5));
journal.journal(makeRI(3), 1, 6, 5, QJMTestUtil.createTxnData(6, 5));
journal.journal(makeRI(4), 1, 11, 5, QJMTestUtil.createTxnData(11, 5));
assertJournaledEditsTxnCountAndContents(1, 7, 7,
NameNodeLayoutVersion.CURRENT_LAYOUT_VERSION);
assertJournaledEditsTxnCountAndContents(1, 30, 15,
NameNodeLayoutVersion.CURRENT_LAYOUT_VERSION);
journal.finalizeLogSegment(makeRI(5), 1, 15);
int newLayoutVersion = NameNodeLayoutVersion.CURRENT_LAYOUT_VERSION - 1;
journal.startLogSegment(makeRI(6), 16, newLayoutVersion);
journal.journal(makeRI(7), 16, 16, 5, QJMTestUtil.createTxnData(16, 5));
assertJournaledEditsTxnCountAndContents(16, 10, 20, newLayoutVersion);
}
private void assertJournaledEditsTxnCountAndContents(int startTxn,
int requestedMaxTxns, int expectedEndTxn, int layoutVersion)
throws Exception {
GetJournaledEditsResponseProto result =
journal.getJournaledEdits(startTxn, requestedMaxTxns);
int expectedTxnCount = expectedEndTxn - startTxn + 1;
ByteArrayOutputStream headerBytes = new ByteArrayOutputStream();
EditLogFileOutputStream.writeHeader(layoutVersion,
new DataOutputStream(headerBytes));
assertEquals(expectedTxnCount, result.getTxnCount());
assertArrayEquals(
Bytes.concat(
headerBytes.toByteArray(),
QJMTestUtil.createTxnData(startTxn, expectedTxnCount)),
result.getEditLog().toByteArray());
}
}