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HDFS-13660. DistCp job fails when new data is appended in the file while the DistCp copy job is running 

This uses the length of the file known at the start of the copy to determine the amount of data to copy.

* If a file is appended to during the copy, the original bytes are copied.
* If a file is truncated during a copy, or the attempt to read the data fails with a truncated stream,
  distcp will now fail. Until now these failures were not detected.

Contributed by Mukund Thakur.

Change-Id: I576a49d951fa48d37a45a7e4c82c47488aa8e884
This commit is contained in:
Mukund Thakur 2019-09-24 11:22:42 +01:00 committed by Steve Loughran
parent 8f1a135118
commit 51c64b357d
No known key found for this signature in database
GPG Key ID: D22CF846DBB162A0
10 changed files with 156 additions and 58 deletions
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6
hadoop-tools/hadoop-distcp/src/main/java/org/apache/hadoop/tools/DistCpConstants.java
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@ -171,4 +171,10 @@ public final class DistCpConstants {
/** Filename of sorted target listing. */
public static final String TARGET_SORTED_FILE = "target_sorted.seq";
public static final String LENGTH_MISMATCH_ERROR_MSG =
"Mismatch in length of source:";
public static final String CHECKSUM_MISMATCH_ERROR_MSG =
"Checksum mismatch between ";
}

10
hadoop-tools/hadoop-distcp/src/main/java/org/apache/hadoop/tools/mapred/CopyCommitter.java
View File

@ -252,7 +252,7 @@ public class CopyCommitter extends FileOutputCommitter {
// This is the last chunk of the splits, consolidate allChunkPaths
try {
concatFileChunks(conf, srcFileStatus.getPath(), targetFile,
allChunkPaths);
allChunkPaths, srcFileStatus);
} catch (IOException e) {
// If the concat failed because a chunk file doesn't exist,
// then we assume that the CopyMapper has skipped copying this
@ -609,7 +609,8 @@ public class CopyCommitter extends FileOutputCommitter {
* Concat the passed chunk files into one and rename it the targetFile.
*/
private void concatFileChunks(Configuration conf, Path sourceFile,
Path targetFile, LinkedList<Path> allChunkPaths)
Path targetFile, LinkedList<Path> allChunkPaths,
CopyListingFileStatus srcFileStatus)
throws IOException {
if (allChunkPaths.size() == 1) {
return;
@ -637,8 +638,9 @@ public class CopyCommitter extends FileOutputCommitter {
LOG.debug("concat: result: " + dstfs.getFileStatus(firstChunkFile));
}
rename(dstfs, firstChunkFile, targetFile);
DistCpUtils.compareFileLengthsAndChecksums(
srcfs, sourceFile, null, dstfs, targetFile, skipCrc);
DistCpUtils.compareFileLengthsAndChecksums(srcFileStatus.getLen(),
srcfs, sourceFile, null, dstfs,
targetFile, skipCrc, srcFileStatus.getLen());
}
/**

3
hadoop-tools/hadoop-distcp/src/main/java/org/apache/hadoop/tools/mapred/CopyMapper.java
View File

@ -139,7 +139,6 @@ public class CopyMapper extends Mapper<Text, CopyListingFileStatus, Text, Text>
public void map(Text relPath, CopyListingFileStatus sourceFileStatus,
Context context) throws IOException, InterruptedException {
Path sourcePath = sourceFileStatus.getPath();
if (LOG.isDebugEnabled())
LOG.debug("DistCpMapper::map(): Received " + sourcePath + ", " + relPath);
@ -354,7 +353,7 @@ public class CopyMapper extends Mapper<Text, CopyListingFileStatus, Text, Text>
if (sameLength && sameBlockSize) {
return skipCrc ||
DistCpUtils.checksumsAreEqual(sourceFS, source.getPath(), null,
targetFS, target.getPath());
targetFS, target.getPath(), source.getLen());
} else {
return false;
}

34
hadoop-tools/hadoop-distcp/src/main/java/org/apache/hadoop/tools/mapred/RetriableFileCopyCommand.java
View File

@ -143,8 +143,9 @@ public class RetriableFileCopyCommand extends RetriableCommand {
offset, context, fileAttributes, sourceChecksum);
if (!source.isSplit()) {
DistCpUtils.compareFileLengthsAndChecksums(sourceFS, sourcePath,
sourceChecksum, targetFS, targetPath, skipCrc);
DistCpUtils.compareFileLengthsAndChecksums(source.getLen(), sourceFS,
sourcePath, sourceChecksum, targetFS,
targetPath, skipCrc, source.getLen());
}
// it's not append or direct write (preferred for s3a) case, thus we first
// write to a temporary file, then rename it to the target path.
@ -247,24 +248,27 @@ public class RetriableFileCopyCommand extends RetriableCommand {
boolean finished = false;
try {
inStream = getInputStream(source, context.getConfiguration());
long fileLength = source2.getLen();
int numBytesToRead = (int) getNumBytesToRead(fileLength, sourceOffset,
bufferSize);
seekIfRequired(inStream, sourceOffset);
int bytesRead = readBytes(inStream, buf);
while (bytesRead >= 0) {
int bytesRead = readBytes(inStream, buf, numBytesToRead);
while (bytesRead > 0) {
if (chunkLength > 0 &&
(totalBytesRead + bytesRead) >= chunkLength) {
bytesRead = (int)(chunkLength - totalBytesRead);
finished = true;
}
totalBytesRead += bytesRead;
if (action == FileAction.APPEND) {
sourceOffset += bytesRead;
}
sourceOffset += bytesRead;
outStream.write(buf, 0, bytesRead);
updateContextStatus(totalBytesRead, context, source2);
if (finished) {
break;
}
bytesRead = readBytes(inStream, buf);
numBytesToRead = (int) getNumBytesToRead(fileLength, sourceOffset,
bufferSize);
bytesRead = readBytes(inStream, buf, numBytesToRead);
}
outStream.close();
outStream = null;
@ -274,6 +278,15 @@ public class RetriableFileCopyCommand extends RetriableCommand {
return totalBytesRead;
}
@VisibleForTesting
long getNumBytesToRead(long fileLength, long position, long bufLength) {
if (position + bufLength < fileLength) {
return bufLength;
} else {
return fileLength - position;
}
}
private void updateContextStatus(long totalBytesRead, Mapper.Context context,
CopyListingFileStatus source2) {
StringBuilder message = new StringBuilder(DistCpUtils.getFormatter()
@ -287,10 +300,11 @@ public class RetriableFileCopyCommand extends RetriableCommand {
context.setStatus(message.toString());
}
private static int readBytes(ThrottledInputStream inStream, byte buf[])
private static int readBytes(ThrottledInputStream inStream, byte[] buf,
int numBytes)
throws IOException {
try {
return inStream.read(buf);
return inStream.read(buf, 0, numBytes);
} catch (IOException e) {
throw new CopyReadException(e);
}

26
hadoop-tools/hadoop-distcp/src/main/java/org/apache/hadoop/tools/util/DistCpUtils.java
View File

@ -35,6 +35,7 @@ import org.apache.hadoop.hdfs.DistributedFileSystem;
import org.apache.hadoop.io.SequenceFile;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.InputFormat;
import org.apache.hadoop.tools.DistCpConstants;
import org.apache.hadoop.tools.CopyListing.AclsNotSupportedException;
import org.apache.hadoop.tools.CopyListing.XAttrsNotSupportedException;
import org.apache.hadoop.tools.CopyListingFileStatus;
@ -565,13 +566,15 @@ public class DistCpUtils {
* @throws IOException if there's an exception while retrieving checksums.
*/
public static boolean checksumsAreEqual(FileSystem sourceFS, Path source,
FileChecksum sourceChecksum, FileSystem targetFS, Path target)
FileChecksum sourceChecksum,
FileSystem targetFS,
Path target, long sourceLen)
throws IOException {
FileChecksum targetChecksum = null;
try {
sourceChecksum = sourceChecksum != null
? sourceChecksum
: sourceFS.getFileChecksum(source);
: sourceFS.getFileChecksum(source, sourceLen);
if (sourceChecksum != null) {
// iff there's a source checksum, look for one at the destination.
targetChecksum = targetFS.getFileChecksum(target);
@ -595,23 +598,22 @@ public class DistCpUtils {
* @param skipCrc The flag to indicate whether to skip checksums.
* @throws IOException if there's a mismatch in file lengths or checksums.
*/
public static void compareFileLengthsAndChecksums(
FileSystem sourceFS, Path source, FileChecksum sourceChecksum,
FileSystem targetFS, Path target, boolean skipCrc) throws IOException {
long srcLen = sourceFS.getFileStatus(source).getLen();
long tgtLen = targetFS.getFileStatus(target).getLen();
if (srcLen != tgtLen) {
public static void compareFileLengthsAndChecksums(long srcLen,
FileSystem sourceFS, Path source, FileChecksum sourceChecksum,
FileSystem targetFS, Path target, boolean skipCrc,
long targetLen) throws IOException {
if (srcLen != targetLen) {
throw new IOException(
"Mismatch in length of source:" + source + " (" + srcLen
+ ") and target:" + target + " (" + tgtLen + ")");
DistCpConstants.LENGTH_MISMATCH_ERROR_MSG + source + " (" + srcLen
+ ") and target:" + target + " (" + targetLen + ")");
}
//At this point, src & dest lengths are same. if length==0, we skip checksum
if ((srcLen != 0) && (!skipCrc)) {
if (!checksumsAreEqual(sourceFS, source, sourceChecksum,
targetFS, target)) {
targetFS, target, srcLen)) {
StringBuilder errorMessage =
new StringBuilder("Checksum mismatch between ")
new StringBuilder(DistCpConstants.CHECKSUM_MISMATCH_ERROR_MSG)
.append(source).append(" and ").append(target).append(".");
boolean addSkipHint = false;
String srcScheme = sourceFS.getScheme();

5
hadoop-tools/hadoop-distcp/src/test/java/org/apache/hadoop/tools/mapred/TestCopyCommitter.java
View File

@ -473,9 +473,12 @@ public class TestCopyCommitter {
if (!skipCrc) {
Assert.fail("Expected commit to fail");
}
Path sourcePath = new Path(sourceBase + srcFilename);
CopyListingFileStatus sourceCurrStatus =
new CopyListingFileStatus(fs.getFileStatus(sourcePath));
Assert.assertFalse(DistCpUtils.checksumsAreEqual(
fs, new Path(sourceBase + srcFilename), null,
fs, new Path(targetBase + srcFilename)));
fs, new Path(targetBase + srcFilename), sourceCurrStatus.getLen()));
} catch(IOException exception) {
if (skipCrc) {
LOG.error("Unexpected exception is found", exception);

56
hadoop-tools/hadoop-distcp/src/test/java/org/apache/hadoop/tools/mapred/TestCopyMapper.java
View File

@ -21,11 +21,16 @@ package org.apache.hadoop.tools.mapred;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.security.PrivilegedAction;
import java.util.ArrayList;
import java.util.EnumSet;
import java.util.List;
import java.util.Random;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
@ -53,6 +58,8 @@ import org.apache.hadoop.tools.DistCpOptions;
import org.apache.hadoop.tools.StubContext;
import org.apache.hadoop.tools.util.DistCpUtils;
import org.apache.hadoop.util.DataChecksum;
import org.apache.hadoop.util.StringUtils;
import org.junit.Assert;
import org.junit.BeforeClass;
import org.junit.Test;
@ -444,6 +451,55 @@ public class TestCopyMapper {
}
}
@Test(timeout = 40000)
public void testCopyWhileAppend() throws Exception {
deleteState();
mkdirs(SOURCE_PATH + "/1");
touchFile(SOURCE_PATH + "/1/3");
CopyMapper copyMapper = new CopyMapper();
StubContext stubContext = new StubContext(getConfiguration(), null, 0);
Mapper<Text, CopyListingFileStatus, Text, Text>.Context context =
stubContext.getContext();
copyMapper.setup(context);
final Path path = new Path(SOURCE_PATH + "/1/3");
int manyBytes = 100000000;
appendFile(path, manyBytes);
ScheduledExecutorService scheduledExecutorService =
Executors.newSingleThreadScheduledExecutor();
Runnable task = new Runnable() {
public void run() {
try {
int maxAppendAttempts = 20;
int appendCount = 0;
while (appendCount < maxAppendAttempts) {
appendFile(path, 1000);
Thread.sleep(200);
appendCount++;
}
} catch (IOException | InterruptedException e) {
LOG.error("Exception encountered ", e);
Assert.fail("Test failed: " + e.getMessage());
}
}
};
scheduledExecutorService.schedule(task, 10, TimeUnit.MILLISECONDS);
try {
copyMapper.map(new Text(DistCpUtils.getRelativePath(
new Path(SOURCE_PATH), path)),
new CopyListingFileStatus(cluster.getFileSystem().getFileStatus(
path)), context);
} catch (Exception ex) {
LOG.error("Exception encountered ", ex);
String exceptionAsString = StringUtils.stringifyException(ex);
if (exceptionAsString.contains(DistCpConstants.LENGTH_MISMATCH_ERROR_MSG) ||
exceptionAsString.contains(DistCpConstants.CHECKSUM_MISMATCH_ERROR_MSG)) {
Assert.fail("Test failed: " + exceptionAsString);
}
} finally {
scheduledExecutorService.shutdown();
}
}
@Test(timeout=40000)
public void testMakeDirFailure() {
try {

25
hadoop-tools/hadoop-distcp/src/test/java/org/apache/hadoop/tools/mapred/TestRetriableFileCopyCommand.java
View File

@ -24,6 +24,8 @@ import org.apache.hadoop.fs.Path;
import org.apache.hadoop.mapreduce.*;
import org.apache.hadoop.tools.CopyListingFileStatus;
import org.apache.hadoop.tools.mapred.CopyMapper.FileAction;
import org.junit.Assert;
import org.junit.Test;
import static org.junit.Assert.*;
import static org.mockito.Mockito.*;
@ -57,5 +59,26 @@ public class TestRetriableFileCopyCommand {
}
assertNotNull("close didn't fail", actualEx);
assertEquals(expectedEx, actualEx);
}
}
@Test(timeout = 40000)
public void testGetNumBytesToRead() {
long pos = 100;
long buffLength = 1024;
long fileLength = 2058;
RetriableFileCopyCommand retriableFileCopyCommand =
new RetriableFileCopyCommand("Testing NumBytesToRead ",
FileAction.OVERWRITE);
long numBytes = retriableFileCopyCommand
.getNumBytesToRead(fileLength, pos, buffLength);
Assert.assertEquals(1024, numBytes);
pos += numBytes;
numBytes = retriableFileCopyCommand
.getNumBytesToRead(fileLength, pos, buffLength);
Assert.assertEquals(934, numBytes);
pos += numBytes;
numBytes = retriableFileCopyCommand
.getNumBytesToRead(fileLength, pos, buffLength);
Assert.assertEquals(0, numBytes);
}
}

45
hadoop-tools/hadoop-distcp/src/test/java/org/apache/hadoop/tools/util/TestDistCpUtils.java
View File

@ -33,8 +33,8 @@ import org.apache.hadoop.hdfs.MiniDFSCluster;
import org.apache.hadoop.hdfs.server.namenode.INodeFile;
import org.apache.hadoop.hdfs.tools.ECAdmin;
import org.apache.hadoop.io.IOUtils;
import org.apache.hadoop.test.GenericTestUtils;
import org.apache.hadoop.tools.CopyListingFileStatus;
import org.apache.hadoop.tools.DistCpConstants;
import org.apache.hadoop.tools.DistCpOptionSwitch;
import org.apache.hadoop.tools.DistCpOptions.FileAttribute;
import org.apache.hadoop.util.ToolRunner;
@ -63,6 +63,7 @@ import static org.apache.hadoop.fs.permission.FsAction.READ;
import static org.apache.hadoop.fs.permission.FsAction.READ_EXECUTE;
import static org.apache.hadoop.fs.permission.FsAction.READ_WRITE;
import static org.apache.hadoop.hdfs.server.namenode.AclTestHelpers.aclEntry;
import static org.apache.hadoop.test.LambdaTestUtils.intercept;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;
@ -1208,7 +1209,7 @@ public class TestDistCpUtils {
}
@Test
public void testCompareFileLengthsAndChecksums() throws IOException {
public void testCompareFileLengthsAndChecksums() throws Throwable {
String base = "/tmp/verify-checksum/";
long srcSeed = System.currentTimeMillis();
@ -1224,22 +1225,18 @@ public class TestDistCpUtils {
Path dstWithLen0 = new Path(base + "dstLen0");
fs.create(srcWithLen0).close();
fs.create(dstWithLen0).close();
DistCpUtils.compareFileLengthsAndChecksums(fs, srcWithLen0,
null, fs, dstWithLen0, false);
DistCpUtils.compareFileLengthsAndChecksums(0, fs, srcWithLen0,
null, fs, dstWithLen0, false, 0);
// different lengths comparison
Path srcWithLen1 = new Path(base + "srcLen1");
Path dstWithLen2 = new Path(base + "dstLen2");
DFSTestUtil.createFile(fs, srcWithLen1, 1, replFactor, srcSeed);
DFSTestUtil.createFile(fs, dstWithLen2, 2, replFactor, srcSeed);
try {
DistCpUtils.compareFileLengthsAndChecksums(fs, srcWithLen1,
null, fs, dstWithLen2, false);
Assert.fail("Expected different lengths comparison to fail!");
} catch (IOException e) {
GenericTestUtils.assertExceptionContains(
"Mismatch in length", e);
}
intercept(IOException.class, DistCpConstants.LENGTH_MISMATCH_ERROR_MSG,
() -> DistCpUtils.compareFileLengthsAndChecksums(1, fs,
srcWithLen1, null, fs, dstWithLen2, false, 2));
// checksums matched
Path srcWithChecksum1 = new Path(base + "srcChecksum1");
@ -1248,28 +1245,24 @@ public class TestDistCpUtils {
replFactor, srcSeed);
DFSTestUtil.createFile(fs, dstWithChecksum1, 1024,
replFactor, srcSeed);
DistCpUtils.compareFileLengthsAndChecksums(fs, srcWithChecksum1,
null, fs, dstWithChecksum1, false);
DistCpUtils.compareFileLengthsAndChecksums(fs, srcWithChecksum1,
DistCpUtils.compareFileLengthsAndChecksums(1024, fs, srcWithChecksum1,
null, fs, dstWithChecksum1, false, 1024);
DistCpUtils.compareFileLengthsAndChecksums(1024, fs, srcWithChecksum1,
fs.getFileChecksum(srcWithChecksum1), fs, dstWithChecksum1,
false);
false, 1024);
// checksums mismatched
Path dstWithChecksum2 = new Path(base + "dstChecksum2");
DFSTestUtil.createFile(fs, dstWithChecksum2, 1024,
replFactor, dstSeed);
try {
DistCpUtils.compareFileLengthsAndChecksums(fs, srcWithChecksum1,
null, fs, dstWithChecksum2, false);
Assert.fail("Expected different checksums comparison to fail!");
} catch (IOException e) {
GenericTestUtils.assertExceptionContains(
"Checksum mismatch", e);
}
intercept(IOException.class, DistCpConstants.CHECKSUM_MISMATCH_ERROR_MSG,
() -> DistCpUtils.compareFileLengthsAndChecksums(1024, fs,
srcWithChecksum1, null, fs, dstWithChecksum2,
false, 1024));
// checksums mismatched but skipped
DistCpUtils.compareFileLengthsAndChecksums(fs, srcWithChecksum1,
null, fs, dstWithChecksum2, true);
DistCpUtils.compareFileLengthsAndChecksums(1024, fs, srcWithChecksum1,
null, fs, dstWithChecksum2, true, 1024);
}
private static Random rand = new Random();

4
hadoop-tools/hadoop-distcp/src/test/java/org/apache/hadoop/tools/util/TestDistCpUtilsWithCombineMode.java
View File

@ -109,7 +109,7 @@ public class TestDistCpUtilsWithCombineMode {
DFSTestUtil.createFile(fs, dst, 256, 1024, 1024,
rf, seed);
// then compare
DistCpUtils.compareFileLengthsAndChecksums(fs, src,
null, fs, dst, false);
DistCpUtils.compareFileLengthsAndChecksums(1024, fs, src,
null, fs, dst, false, 1024);
}
}