MAPREDUCE-5176. Add annotation for tagging tasks as responsive to

preemption. Contributed by Carlo Curino, cdouglas


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1488105 13f79535-47bb-0310-9956-ffa450edef68

hadoop-mapreduce-project/CHANGES.txt

@@ -112,6 +112,9 @@ Release 2.0.5-beta - UNRELEASED
     FileOuputFormat.Counter for binary compatibility with 1.x mapred APIs.
     (Mayank Bansal via vinodkv)
 
+    MAPREDUCE-5176. Add annotation for tagging tasks as responsive to
+    preemption. (Carlo Curino, cdouglas)
+
   OPTIMIZATIONS
 
     MAPREDUCE-4974. Optimising the LineRecordReader initialize() method 

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/Reducer.java

@@ -23,8 +23,7 @@ import java.io.IOException;
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.classification.InterfaceStability;
 import org.apache.hadoop.conf.Configuration;
-import org.apache.hadoop.io.RawComparator;
-import org.apache.hadoop.mapred.RawKeyValueIterator;
+import org.apache.hadoop.mapreduce.task.annotation.Checkpointable;
 
 import java.util.Iterator;
 
@@ -119,6 +118,7 @@ import java.util.Iterator;
  * @see Mapper
  * @see Partitioner
  */
+@Checkpointable
 @InterfaceAudience.Public
 @InterfaceStability.Stable
 public class Reducer<KEYIN,VALUEIN,KEYOUT,VALUEOUT> {

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/lib/output/FileOutputCommitter.java

@@ -154,7 +154,7 @@ public class FileOutputCommitter extends OutputCommitter {
    * @param appAttemptId the ID of the application attempt for this job.
    * @return the path to store job attempt data.
    */
-  private Path getJobAttemptPath(int appAttemptId) {
+  protected Path getJobAttemptPath(int appAttemptId) {
     return getJobAttemptPath(appAttemptId, getOutputPath());
   }
   
@@ -232,7 +232,7 @@ public class FileOutputCommitter extends OutputCommitter {
    * @param context the context of any task.
    * @return the path where the output of a committed task is stored.
    */
-  private Path getCommittedTaskPath(int appAttemptId, TaskAttemptContext context) {
+  protected Path getCommittedTaskPath(int appAttemptId, TaskAttemptContext context) {
     return new Path(getJobAttemptPath(appAttemptId),
         String.valueOf(context.getTaskAttemptID().getTaskID()));
   }

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/lib/output/PartialFileOutputCommitter.java

@@ -0,0 +1,106 @@
+/**
+ * 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.mapreduce.lib.output;
+
+import java.io.IOException;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.classification.InterfaceStability;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.FileSystem;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.mapreduce.JobContext;
+import org.apache.hadoop.mapreduce.OutputCommitter;
+import org.apache.hadoop.mapreduce.TaskAttemptContext;
+import org.apache.hadoop.mapreduce.TaskAttemptID;
+import org.apache.hadoop.mapreduce.TaskID;
+import org.apache.hadoop.mapreduce.task.annotation.Checkpointable;
+
+import com.google.common.annotations.VisibleForTesting;
+
+/** An {@link OutputCommitter} that commits files specified
+ * in job output directory i.e. ${mapreduce.output.fileoutputformat.outputdir}.
+ **/
+@Checkpointable
+@InterfaceAudience.Public
+@InterfaceStability.Evolving
+public class PartialFileOutputCommitter
+    extends FileOutputCommitter implements PartialOutputCommitter {
+
+  private static final Log LOG =
+    LogFactory.getLog(PartialFileOutputCommitter.class);
+
+
+  public PartialFileOutputCommitter(Path outputPath,
+                             TaskAttemptContext context) throws IOException {
+    super(outputPath, context);
+  }
+
+  public PartialFileOutputCommitter(Path outputPath,
+                             JobContext context) throws IOException {
+    super(outputPath, context);
+  }
+
+  @Override
+  public Path getCommittedTaskPath(int appAttemptId, TaskAttemptContext context) {
+    return new Path(getJobAttemptPath(appAttemptId),
+        String.valueOf(context.getTaskAttemptID()));
+  }
+
+  @VisibleForTesting
+  FileSystem fsFor(Path p, Configuration conf) throws IOException {
+    return p.getFileSystem(conf);
+  }
+
+  @Override
+  public void cleanUpPartialOutputForTask(TaskAttemptContext context)
+      throws IOException {
+
+    // we double check this is never invoked from a non-preemptable subclass.
+    // This should never happen, since the invoking codes is checking it too,
+    // but it is safer to double check. Errors handling this would produce
+    // inconsistent output.
+
+    if (!this.getClass().isAnnotationPresent(Checkpointable.class)) {
+      throw new IllegalStateException("Invoking cleanUpPartialOutputForTask() " +
+          "from non @Preemptable class");
+    }
+    FileSystem fs =
+      fsFor(getTaskAttemptPath(context), context.getConfiguration());
+
+    LOG.info("cleanUpPartialOutputForTask: removing everything belonging to " +
+        context.getTaskAttemptID().getTaskID() + " in: " +
+        getCommittedTaskPath(context).getParent());
+
+    final TaskAttemptID taid = context.getTaskAttemptID();
+    final TaskID tid = taid.getTaskID();
+    Path pCommit = getCommittedTaskPath(context).getParent();
+    // remove any committed output
+    for (int i = 0; i < taid.getId(); ++i) {
+      TaskAttemptID oldId = new TaskAttemptID(tid, i);
+      Path pTask = new Path(pCommit, oldId.toString());
+      if (fs.exists(pTask) && !fs.delete(pTask, true)) {
+        throw new IOException("Failed to delete " + pTask);
+      }
+    }
+  }
+
+}

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/lib/output/PartialOutputCommitter.java

@@ -0,0 +1,43 @@
+/**
+ * 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.mapreduce.lib.output;
+
+import java.io.IOException;
+
+import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.classification.InterfaceStability;
+import org.apache.hadoop.mapreduce.TaskAttemptContext;
+
+/**
+ * Interface for an {@link org.apache.hadoop.mapreduce.OutputCommitter}
+ * implementing partial commit of task output, as during preemption.
+ */
+@InterfaceAudience.Public
+@InterfaceStability.Evolving
+public interface PartialOutputCommitter {
+
+  /**
+   * Remove all previously committed outputs from prior executions of this task.
+   * @param context Context for cleaning up previously promoted output.
+   * @throws IOException If cleanup fails, then the state of the task my not be
+   *                     well defined.
+   */
+  public void cleanUpPartialOutputForTask(TaskAttemptContext context)
+    throws IOException;
+
+}

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/task/annotation/Checkpointable.java

@@ -0,0 +1,42 @@
+/**
+ * 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.mapreduce.task.annotation;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.classification.InterfaceStability;
+
+/**
+ * Contract representing to the framework that the task can be safely preempted
+ * and restarted between invocations of the user-defined function.
+ *
+ * This is often true when the result of a function does not rely on state
+ * derived from previous elements in the record stream, but the guarantee is
+ * left as an exercise to the implementor.
+ */
+@Documented
+@Target(ElementType.TYPE)
+@Retention(RetentionPolicy.RUNTIME)
+@InterfaceAudience.Public
+@InterfaceStability.Evolving
+public @interface Checkpointable { }

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/test/java/org/apache/hadoop/mapreduce/lib/output/TestPreemptableFileOutputCommitter.java

@@ -0,0 +1,101 @@
+/**
+ * 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.mapreduce.lib.output;
+
+import java.io.FileNotFoundException;
+import java.io.IOException;
+
+import org.apache.hadoop.mapreduce.task.annotation.Checkpointable;
+import org.junit.Test;
+import static org.mockito.Mockito.*;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.FileStatus;
+import org.apache.hadoop.fs.FileSystem;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.mapreduce.MRJobConfig;
+import org.apache.hadoop.mapreduce.TaskAttemptContext;
+import org.apache.hadoop.mapreduce.TaskAttemptID;
+import org.apache.hadoop.mapreduce.TaskType;
+
+public class TestPreemptableFileOutputCommitter {
+
+  @Test
+  public void testPartialOutputCleanup()
+      throws FileNotFoundException, IllegalArgumentException, IOException {
+
+    Configuration conf = new Configuration(false);
+    conf.setInt(MRJobConfig.APPLICATION_ATTEMPT_ID, 1);
+    TaskAttemptID tid0 =
+      new TaskAttemptID("1363718006656", 1, TaskType.REDUCE, 14, 3);
+
+    Path p = spy(new Path("/user/hadoop/out"));
+    Path a = new Path("hdfs://user/hadoop/out");
+    Path p0 = new Path(a, "_temporary/1/attempt_1363718006656_0001_r_000014_0");
+    Path p1 = new Path(a, "_temporary/1/attempt_1363718006656_0001_r_000014_1");
+    Path p2 = new Path(a, "_temporary/1/attempt_1363718006656_0001_r_000013_0");
+    // (p3 does not exist)
+    Path p3 = new Path(a, "_temporary/1/attempt_1363718006656_0001_r_000014_2");
+
+    FileStatus[] fsa = new FileStatus[3];
+    fsa[0] = new FileStatus();
+    fsa[0].setPath(p0);
+    fsa[1] = new FileStatus();
+    fsa[1].setPath(p1);
+    fsa[2] = new FileStatus();
+    fsa[2].setPath(p2);
+
+    final FileSystem fs = mock(FileSystem.class);
+    when(fs.exists(eq(p0))).thenReturn(true);
+    when(fs.exists(eq(p1))).thenReturn(true);
+    when(fs.exists(eq(p2))).thenReturn(true);
+    when(fs.exists(eq(p3))).thenReturn(false);
+    when(fs.delete(eq(p0), eq(true))).thenReturn(true);
+    when(fs.delete(eq(p1), eq(true))).thenReturn(true);
+    doReturn(fs).when(p).getFileSystem(any(Configuration.class));
+    when(fs.makeQualified(eq(p))).thenReturn(a);
+
+    TaskAttemptContext context = mock(TaskAttemptContext.class);
+    when(context.getTaskAttemptID()).thenReturn(tid0);
+    when(context.getConfiguration()).thenReturn(conf);
+
+    PartialFileOutputCommitter foc = new TestPFOC(p, context, fs);
+
+    foc.cleanUpPartialOutputForTask(context);
+    verify(fs).delete(eq(p0), eq(true));
+    verify(fs).delete(eq(p1), eq(true));
+    verify(fs, never()).delete(eq(p3), eq(true));
+    verify(fs, never()).delete(eq(p2), eq(true));
+  }
+
+  @Checkpointable
+  static class TestPFOC extends PartialFileOutputCommitter {
+    final FileSystem fs;
+    TestPFOC(Path outputPath, TaskAttemptContext ctxt, FileSystem fs)
+        throws IOException {
+      super(outputPath, ctxt);
+      this.fs = fs;
+    }
+    @Override
+    FileSystem fsFor(Path p, Configuration conf) {
+      return fs;
+    }
+  }
+
+}