YARN-4380. TestResourceLocalizationService.testDownloadingResourcesOnContainerKill fails intermittently. Contributed by Varun Saxena.

(cherry picked from commit 0656d2dc83af6a48a8d8d0e37cdf1f813124f366)

Conflicts:
	hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/test/java/org/apache/hadoop/yarn/server/nodemanager/containermanager/localizer/TestResourceLocalizationService.java

hadoop-yarn-project/CHANGES.txt

@@ -34,6 +34,9 @@ Release 2.7.3 - UNRELEASED
     YARN-4365. FileSystemNodeLabelStore should check for root dir existence on
     startup (Kuhu Shukla via jlowe)
 
+    YARN-4380. TestResourceLocalizationService.testDownloadingResourcesOnContainerKill
+    fails intermittently. (Varun Saxena via ozawa)
+
 Release 2.7.2 - UNRELEASED
 
   INCOMPATIBLE CHANGES

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/test/java/org/apache/hadoop/yarn/server/nodemanager/containermanager/localizer/TestResourceLocalizationService.java

@@ -63,6 +63,7 @@ import java.util.Set;
 import java.util.concurrent.BrokenBarrierException;
 import java.util.concurrent.CyclicBarrier;
 import java.util.concurrent.Future;
+import java.util.concurrent.atomic.AtomicInteger;
 
 import org.apache.hadoop.fs.Options;
 import org.junit.Assert;
@@ -1091,16 +1092,23 @@ public class TestResourceLocalizationService {
 
   private static class DummyExecutor extends DefaultContainerExecutor {
     private volatile boolean stopLocalization = false;
+    private AtomicInteger numLocalizers = new AtomicInteger(0);
     @Override
     public void startLocalizer(Path nmPrivateContainerTokensPath,
         InetSocketAddress nmAddr, String user, String appId, String locId,
         LocalDirsHandlerService dirsHandler) throws IOException,
         InterruptedException {
+      numLocalizers.incrementAndGet();
       while (!stopLocalization) {
         Thread.yield();
       }
     }
-    void setStopLocalization() {
+    private void waitForLocalizers(int num) {
+      while (numLocalizers.intValue() < num) {
+        Thread.yield();
+      }
+    }
+    private void setStopLocalization() {
       stopLocalization = true;
     }
   }
@@ -1243,6 +1251,10 @@ public class TestResourceLocalizationService {
       spyService.handle(new ContainerLocalizationRequestEvent(c2, rsrcs1));
 
       dispatcher.await();
+      // Wait for localizers of both container c1 and c2 to begin.
+      exec.waitForLocalizers(2);
+      LocalizerRunner locC1 =
+          spyService.getLocalizerRunner(c1.getContainerId().toString());
       final String containerIdStr = c1.getContainerId().toString();
       // Heartbeats from container localizer
       LocalResourceStatus rsrc1success = mock(LocalResourceStatus.class);
@@ -1310,6 +1322,10 @@ public class TestResourceLocalizationService {
       Set<Path> paths =
           Sets.newHashSet(new Path(locPath1), new Path(locPath1 + "_tmp"),
               new Path(locPath2), new Path(locPath2 + "_tmp"));
+      // Wait for localizer runner thread for container c1 to finish.
+      while (locC1.getState() != Thread.State.TERMINATED) {
+        Thread.sleep(50);
+      }
       // Verify if downloading resources were submitted for deletion.
       verify(delService).delete(eq(user),
           (Path) eq(null), argThat(new DownloadingPathsMatcher(paths)));