MAPREDUCE-6441. Improve temporary directory name generation in LocalDistributedCacheManager for concurrent processes (wattsinabox, rchiang, haibochen via rkanter)

This commit is contained in:
Robert Kanter 2018-03-26 14:55:53 -07:00
parent fcea5a4d79
commit edb202e493
3 changed files with 78 additions and 32 deletions

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@ -37,7 +37,7 @@
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Future;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.atomic.AtomicLong;
import java.util.UUID;
import org.apache.hadoop.fs.FileContext;
import org.apache.hadoop.fs.FileUtil;
@ -82,7 +82,7 @@ class LocalDistributedCacheManager {
* @param conf
* @throws IOException
*/
public void setup(JobConf conf) throws IOException {
public void setup(JobConf conf, JobID jobId) throws IOException {
File workDir = new File(System.getProperty("user.dir"));
// Generate YARN local resources objects corresponding to the distributed
@ -91,8 +91,6 @@ public void setup(JobConf conf) throws IOException {
new LinkedHashMap<String, LocalResource>();
MRApps.setupDistributedCache(conf, localResources);
// Generating unique numbers for FSDownload.
AtomicLong uniqueNumberGenerator =
new AtomicLong(System.currentTimeMillis());
// Find which resources are to be put on the local classpath
Map<String, Path> classpaths = new HashMap<String, Path>();
@ -124,9 +122,10 @@ public void setup(JobConf conf) throws IOException {
Path destPath = localDirAllocator.getLocalPathForWrite(".", conf);
Map<LocalResource, Future<Path>> resourcesToPaths = Maps.newHashMap();
for (LocalResource resource : localResources.values()) {
Path destPathForDownload = new Path(destPath,
jobId.toString() + "_" + UUID.randomUUID().toString());
Callable<Path> download =
new FSDownload(localFSFileContext, ugi, conf, new Path(destPath,
Long.toString(uniqueNumberGenerator.incrementAndGet())),
new FSDownload(localFSFileContext, ugi, conf, destPathForDownload,
resource);
Future<Path> future = exec.submit(download);
resourcesToPaths.put(resource, future);

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@ -169,7 +169,7 @@ public Job(JobID jobid, String jobSubmitDir) throws IOException {
// Manage the distributed cache. If there are files to be copied,
// this will trigger localFile to be re-written again.
localDistributedCacheManager = new LocalDistributedCacheManager();
localDistributedCacheManager.setup(conf);
localDistributedCacheManager.setup(conf, jobid);
// Write out configuration file. Instead of copying it from
// systemJobFile, we re-write it, since setup(), above, may have

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@ -32,6 +32,13 @@
import java.net.URI;
import java.util.HashMap;
import java.util.Map;
import java.util.ArrayList;
import java.util.concurrent.Callable;
import java.util.concurrent.CyclicBarrier;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.FileStatus;
@ -120,6 +127,7 @@ public void seek(long position) {}
@Test
public void testDownload() throws Exception {
JobID jobId = new JobID();
JobConf conf = new JobConf();
conf.setClass("fs.mock.impl", MockFileSystem.class, FileSystem.class);
@ -176,7 +184,7 @@ public FSDataInputStream answer(InvocationOnMock args) throws Throwable {
conf.set(MRConfig.LOCAL_DIR, localDir.getAbsolutePath());
LocalDistributedCacheManager manager = new LocalDistributedCacheManager();
try {
manager.setup(conf);
manager.setup(conf, jobId);
assertTrue(link.exists());
} finally {
manager.close();
@ -186,6 +194,7 @@ public FSDataInputStream answer(InvocationOnMock args) throws Throwable {
@Test
public void testEmptyDownload() throws Exception {
JobID jobId = new JobID();
JobConf conf = new JobConf();
conf.setClass("fs.mock.impl", MockFileSystem.class, FileSystem.class);
@ -221,7 +230,7 @@ public FSDataInputStream answer(InvocationOnMock args) throws Throwable {
conf.set(MRConfig.LOCAL_DIR, localDir.getAbsolutePath());
LocalDistributedCacheManager manager = new LocalDistributedCacheManager();
try {
manager.setup(conf);
manager.setup(conf, jobId);
} finally {
manager.close();
}
@ -230,6 +239,7 @@ public FSDataInputStream answer(InvocationOnMock args) throws Throwable {
@Test
public void testDuplicateDownload() throws Exception {
JobID jobId = new JobID();
JobConf conf = new JobConf();
conf.setClass("fs.mock.impl", MockFileSystem.class, FileSystem.class);
@ -287,11 +297,48 @@ public FSDataInputStream answer(InvocationOnMock args) throws Throwable {
conf.set(MRConfig.LOCAL_DIR, localDir.getAbsolutePath());
LocalDistributedCacheManager manager = new LocalDistributedCacheManager();
try {
manager.setup(conf);
manager.setup(conf, jobId);
assertTrue(link.exists());
} finally {
manager.close();
}
assertFalse(link.exists());
}
/**
* This test tries to replicate the issue with the previous version of
* {@ref LocalDistributedCacheManager} when the resulting timestamp is
* identical as that in another process. Unfortunately, it is difficult
* to mimic such behavior in a single process unit test. And mocking
* the unique id (timestamp previously, UUID otherwise) won't prove the
* validity of one approach over the other.
*/
@Test
public void testMultipleCacheSetup() throws Exception {
JobID jobId = new JobID();
JobConf conf = new JobConf();
LocalDistributedCacheManager manager = new LocalDistributedCacheManager();
final int threadCount = 10;
final CyclicBarrier barrier = new CyclicBarrier(threadCount);
ArrayList<Callable<Void>> setupCallable = new ArrayList<>();
for (int i = 0; i < threadCount; ++i) {
setupCallable.add(() -> {
barrier.await();
manager.setup(conf, jobId);
return null;
});
}
ExecutorService ePool = Executors.newFixedThreadPool(threadCount);
try {
for (Future<Void> future : ePool.invokeAll(setupCallable)) {
future.get();
}
} finally {
ePool.shutdown();
manager.close();
}
}
}