commit ee843615579433c867f3f00c4901d7c4b99737d9

Author: Vinod Kumar <vinodkv@yahoo-inc.com>
Date:   Fri Apr 23 15:46:55 2010 +0530

    MAPREDUCE:1397. From https://issues.apache.org/jira/secure/attachment/12442657/patch-1397-ydist.txt
    
    +++ b/YAHOO-CHANGES.txt
    +    MAPREDUCE-1397. NullPointerException observed during task failures.
    +    (Amareshwari Sriramadasu via vinodkv)
    +


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-0.20-security-patches@1077421 13f79535-47bb-0310-9956-ffa450edef68

src/mapred/org/apache/hadoop/mapred/JvmManager.java

@@ -32,6 +32,7 @@ import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.mapred.TaskController.TaskControllerContext;
 import org.apache.hadoop.mapred.TaskTracker.TaskInProgress;
+import org.apache.hadoop.mapreduce.TaskType;
 import org.apache.hadoop.mapreduce.server.tasktracker.JVMInfo;
 import org.apache.hadoop.mapreduce.server.tasktracker.userlogs.JvmFinishedEvent;
 import org.apache.hadoop.util.ProcessTree;
@@ -42,9 +43,9 @@ class JvmManager {
   public static final Log LOG =
     LogFactory.getLog("org.apache.hadoop.mapred.JvmManager");
 
-  JvmManagerForType mapJvmManager;
+  private JvmManagerForType mapJvmManager;
 
-  JvmManagerForType reduceJvmManager;
+  private JvmManagerForType reduceJvmManager;
   
   public JvmEnv constructJvmEnv(List<String> setup, Vector<String>vargs,
       File stdout,File stderr,long logSize, File workDir, 
@@ -58,6 +59,16 @@ class JvmManager {
     reduceJvmManager = new JvmManagerForType(tracker.getMaxCurrentReduceTasks(),
         false, tracker);
   }
+
+  //called from unit tests
+  JvmManagerForType getJvmManagerForType(TaskType type) {
+    if (type.equals(TaskType.MAP)) {
+      return mapJvmManager;
+    } else if (type.equals(TaskType.REDUCE)) {
+      return reduceJvmManager;
+    }
+    return null;
+  }
   
   /*
    * Saves pid of the given taskJvm
@@ -161,7 +172,7 @@ class JvmManager {
           tracker.getTaskController()));
   }
 
-  private static class JvmManagerForType {
+  static class JvmManagerForType {
     //Mapping from the JVM IDs to running Tasks
     Map <JVMId,TaskRunner> jvmToRunningTask = 
       new HashMap<JVMId, TaskRunner>();
@@ -257,7 +268,7 @@ class JvmManager {
     synchronized public void killJvm(JVMId jvmId) {
       JvmRunner jvmRunner;
       if ((jvmRunner = jvmIdToRunner.get(jvmId)) != null) {
-        jvmRunner.kill();
+        killJvmRunner(jvmRunner);
       }
     }
     
@@ -270,10 +281,15 @@ class JvmManager {
       List <JvmRunner> list = new ArrayList<JvmRunner>();
       list.addAll(jvmIdToRunner.values());
       for (JvmRunner jvm : list) {
-        jvm.kill();
+        killJvmRunner(jvm);
       }
     }
-    
+
+    private synchronized void killJvmRunner(JvmRunner jvmRunner) {
+      jvmRunner.kill();
+      removeJvm(jvmRunner.jvmId);
+    }
+
     synchronized private void removeJvm(JVMId jvmId) {
       jvmIdToRunner.remove(jvmId);
       jvmIdToPid.remove(jvmId);
@@ -334,7 +350,7 @@ class JvmManager {
       if (spawnNewJvm) {
         if (runnerToKill != null) {
           LOG.info("Killing JVM: " + runnerToKill.jvmId);
-          runnerToKill.kill();
+          killJvmRunner(runnerToKill);
         }
         spawnNewJvm(jobId, env, t);
         return;
@@ -396,7 +412,7 @@ class JvmManager {
       }
     }
 
-    private class JvmRunner extends Thread {
+    class JvmRunner extends Thread {
       JvmEnv env;
       volatile boolean killed = false;
       volatile int numTasksRan;
@@ -459,9 +475,8 @@ class JvmManager {
         }
       }
 
-      public void kill() {
+      synchronized void kill() {
         if (!killed) {
-          killed = true;
           TaskController controller = tracker.getTaskController();
           // Check inital context before issuing a kill to prevent situations
           // where kill is issued before task is launched.
@@ -477,7 +492,7 @@ class JvmManager {
             LOG.info(String.format("JVM Not killed %s but just removed", jvmId
                 .toString()));
           }
-          removeJvm(jvmId);
+          killed = true;
         }
       }
 

src/mapred/org/apache/hadoop/mapred/TaskRunner.java

@@ -212,14 +212,7 @@ abstract class TaskRunner extends Thread {
       errorInfo = getVMEnvironment(errorInfo, workDir, conf, env, taskid,
                                    logSize);
 
-      jvmManager.launchJvm(this, 
-          jvmManager.constructJvmEnv(setup,vargs,stdout,stderr,logSize, 
-              workDir, env, conf));
-      synchronized (lock) {
-        while (!done) {
-          lock.wait();
-        }
-      }
+      launchJvmAndWait(setup, vargs, stdout, stderr, logSize, workDir, env);
       tracker.getTaskTrackerInstrumentation().reportTaskEnd(t.getTaskID());
       if (exitCodeSet) {
         if (!killed && exitCode != 0) {
@@ -263,6 +256,18 @@ abstract class TaskRunner extends Thread {
     }
   }
 
+  void launchJvmAndWait(List<String> setup, Vector<String> vargs, File stdout,
+      File stderr, long logSize, File workDir, Map<String, String> env)
+      throws InterruptedException {
+    jvmManager.launchJvm(this, jvmManager.constructJvmEnv(setup, vargs, stdout,
+        stderr, logSize, workDir, env, conf));
+    synchronized (lock) {
+      while (!done) {
+        lock.wait();
+      }
+    }
+  }
+
   /**
    * Prepare the log files for the task
    * 

src/mapred/org/apache/hadoop/mapred/TaskTracker.java

@@ -263,7 +263,7 @@ public class TaskTracker
   private MapEventsFetcherThread mapEventsFetcher;
   int workerThreads;
   CleanupQueue directoryCleanupThread;
-  volatile JvmManager jvmManager;
+  private volatile JvmManager jvmManager;
   
   private TaskMemoryManagerThread taskMemoryManager;
   private boolean taskMemoryManagerEnabled = true;
@@ -1953,7 +1953,12 @@ public class TaskTracker
   public JvmManager getJvmManagerInstance() {
     return jvmManager;
   }
-  
+
+  // called from unit test  
+  void setJvmManagerInstance(JvmManager jvmManager) {
+    this.jvmManager = jvmManager;
+  }
+
   private void addToTaskQueue(LaunchTaskAction action) {
     if (action.getTask().isMapTask()) {
       mapLauncher.addToTaskQueue(action);
@@ -3583,6 +3588,16 @@ public class TaskTracker
     return maxReduceSlots;
   }
 
+  //called from unit test
+  synchronized void setMaxMapSlots(int mapSlots) {
+    maxMapSlots = mapSlots;
+  }
+
+  //called from unit test
+  synchronized void setMaxReduceSlots(int reduceSlots) {
+    maxReduceSlots = reduceSlots;
+  }
+
   /**
    * Is the TaskMemoryManager Enabled on this system?
    * @return true if enabled, false otherwise.

src/test/org/apache/hadoop/mapred/TestJvmManager.java

@@ -0,0 +1,184 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.mapred;
+
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.FileReader;
+import java.io.IOException;
+import java.util.Vector;
+
+import org.apache.hadoop.fs.FileUtil;
+import org.apache.hadoop.mapred.JvmManager.JvmManagerForType;
+import org.apache.hadoop.mapred.JvmManager.JvmManagerForType.JvmRunner;
+import org.apache.hadoop.mapred.TaskTracker.TaskInProgress;
+import org.apache.hadoop.mapreduce.TaskType;
+import org.apache.hadoop.mapreduce.server.tasktracker.userlogs.UserLogManager;
+import org.junit.After;
+import static org.junit.Assert.*;
+import org.junit.Before;
+import org.junit.Test;
+
+public class TestJvmManager {
+  private static File TEST_DIR = new File(System.getProperty("test.build.data",
+      "/tmp"), TestJvmManager.class.getSimpleName());
+  private static int MAP_SLOTS = 1;
+  private static int REDUCE_SLOTS = 1;
+  private TaskTracker tt;
+  private JvmManager jvmManager;
+  private JobConf ttConf;
+
+  @Before
+  public void setUp() {
+    TEST_DIR.mkdirs();
+  }
+
+  @After
+  public void tearDown() throws IOException {
+    FileUtil.fullyDelete(TEST_DIR);
+  }
+
+  public TestJvmManager() throws Exception {
+    tt = new TaskTracker();
+    ttConf = new JobConf();
+    ttConf.setLong("mapred.tasktracker.tasks.sleeptime-before-sigkill", 2000);
+    tt.setConf(ttConf);
+    tt.setMaxMapSlots(MAP_SLOTS);
+    tt.setMaxReduceSlots(REDUCE_SLOTS);
+    tt.setTaskController(new DefaultTaskController());
+    jvmManager = new JvmManager(tt);
+    tt.setJvmManagerInstance(jvmManager);
+    tt.setUserLogManager(new UserLogManager(ttConf));
+  }
+
+  // write a shell script to execute the command.
+  private File writeScript(String fileName, String cmd, File pidFile) throws IOException {
+    File script = new File(TEST_DIR, fileName);
+    FileOutputStream out = new FileOutputStream(script);
+    // write pid into a file
+    out.write(("echo $$ >" + pidFile.toString() + ";").getBytes());
+    // ignore SIGTERM
+    out.write(("trap '' 15\n").getBytes());
+    // write the actual command it self.
+    out.write(cmd.getBytes());
+    out.close();
+    script.setExecutable(true);
+    return script;
+  }
+  
+  /**
+   * Tests the jvm kill from JvmRunner and JvmManager simultaneously.
+   * 
+   * Starts a process, which sleeps for 60 seconds, in a thread.
+   * Calls JvmRunner.kill() in a thread.
+   * Also calls JvmManager.taskKilled().
+   * Makes sure that the jvm is killed and JvmManager could launch another task
+   * properly.
+   * @throws Exception
+   */
+  @Test
+  public void testJvmKill() throws Exception {
+    JvmManagerForType mapJvmManager = jvmManager
+        .getJvmManagerForType(TaskType.MAP);
+    // launch a jvm
+    JobConf taskConf = new JobConf(ttConf);
+    TaskAttemptID attemptID = new TaskAttemptID("test", 0, true, 0, 0);
+    Task task = new MapTask(null, attemptID, 0, null, MAP_SLOTS);
+    task.setConf(taskConf);
+    TaskInProgress tip = tt.new TaskInProgress(task, taskConf);
+    File pidFile = new File(TEST_DIR, "pid");
+    final TaskRunner taskRunner = task.createRunner(tt, tip);
+    // launch a jvm which sleeps for 60 seconds
+    final Vector<String> vargs = new Vector<String>(2);
+    vargs.add(writeScript("SLEEP", "sleep 60\n", pidFile).getAbsolutePath());
+    final File workDir = new File(TEST_DIR, "work");
+    workDir.mkdir();
+    final File stdout = new File(TEST_DIR, "stdout");
+    final File stderr = new File(TEST_DIR, "stderr");
+
+    // launch the process and wait in a thread, till it finishes
+    Thread launcher = new Thread() {
+      public void run() {
+        try {
+          taskRunner.launchJvmAndWait(null, vargs, stdout, stderr, 100,
+              workDir, null);
+        } catch (InterruptedException e) {
+          e.printStackTrace();
+          return;
+        }
+      }
+    };
+    launcher.start();
+    // wait till the jvm is launched
+    // this loop waits for at most 1 second
+    for (int i = 0; i < 10; i++) {
+      if (pidFile.exists()) {
+        break;
+      }
+      UtilsForTests.waitFor(100);
+    }
+    // assert that the process is launched
+    assertTrue("pidFile is not present", pidFile.exists());
+    
+    // imitate Child code.
+    // set pid in jvmManager
+    BufferedReader in = new  BufferedReader(new FileReader(pidFile));
+    String pid = in.readLine();
+    in.close();
+    JVMId jvmid = mapJvmManager.runningTaskToJvm.get(taskRunner);
+    jvmManager.setPidToJvm(jvmid, pid);
+
+    // kill JvmRunner
+    final JvmRunner jvmRunner = mapJvmManager.jvmIdToRunner.get(jvmid);
+    Thread killer = new Thread() {
+      public void run() {
+        jvmRunner.kill();
+      }
+    };
+    killer.start();
+    
+    //wait for a while so that killer thread is started.
+    Thread.sleep(100);
+
+    // kill the jvm externally
+    taskRunner.kill();
+
+    assertTrue(jvmRunner.killed);
+
+    // launch another jvm and see it finishes properly
+    attemptID = new TaskAttemptID("test", 0, true, 0, 1);
+    task = new MapTask(null, attemptID, 0, null, MAP_SLOTS);
+    task.setConf(taskConf);
+    tip = tt.new TaskInProgress(task, taskConf);
+    TaskRunner taskRunner2 = task.createRunner(tt, tip);
+    // build dummy vargs to call ls
+    Vector<String> vargs2 = new Vector<String>(1);
+    vargs2.add(writeScript("LS", "ls", pidFile).getAbsolutePath());
+    File workDir2 = new File(TEST_DIR, "work2");
+    workDir.mkdir();
+    File stdout2 = new File(TEST_DIR, "stdout2");
+    File stderr2 = new File(TEST_DIR, "stderr2");
+    taskRunner2.launchJvmAndWait(null, vargs2, stdout2, stderr2, 100, workDir2,
+        null);
+    // join all the threads
+    killer.join();
+    jvmRunner.join();
+    launcher.join();
+  }
+}