HDFS-1942. Datanode must exist when all the block pool service threads exit. Contributed by Bharath Mundlapudi.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1136132 13f79535-47bb-0310-9956-ffa450edef68

hdfs/CHANGES.txt

@@ -740,6 +740,9 @@ Trunk (unreleased changes)
     HDFS-2069. Incorrect default trash interval value in the docs.
     (Harsh J Chouraria via eli)
 
+    HDFS-1942. Datanode must exist when all the block pool service threads
+    exit. (Bharath Mundlapudi via suresh)
+
 Release 0.22.0 - Unreleased
 
   INCOMPATIBLE CHANGES

hdfs/src/java/org/apache/hadoop/hdfs/server/datanode/DataNode.java

@@ -1425,6 +1425,10 @@ BPOfferService[] getAllBpOs() {
     return blockPoolManager.getAllNamenodeThreads();
   }
   
+  int getBpOsCount() {
+    return blockPoolManager.getAllNamenodeThreads().length;
+  }
+  
   /**
    * Initializes the {@link #data}. The initialization is done only once, when
    * handshake with the the first namenode is completed.
@@ -2134,6 +2138,10 @@ void join() {
     while (shouldRun) {
       try {
         blockPoolManager.joinAll();
+        if (blockPoolManager.getAllNamenodeThreads() != null
+            && blockPoolManager.getAllNamenodeThreads().length == 0) {
+          shouldRun = false;
+        }
         Thread.sleep(2000);
       } catch (InterruptedException ex) {
         LOG.warn("Received exception in Datanode#join: " + ex);

hdfs/src/test/hdfs/org/apache/hadoop/hdfs/server/datanode/TestDataNodeExit.java

@@ -0,0 +1,91 @@
+/**
+ * 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.hdfs.server.datanode;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import java.io.IOException;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.hdfs.DFSConfigKeys;
+import org.apache.hadoop.hdfs.HdfsConfiguration;
+import org.apache.hadoop.hdfs.MiniDFSCluster;
+import org.apache.hadoop.hdfs.server.datanode.DataNode.BPOfferService;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+/** 
+ * Tests if DataNode process exits if all Block Pool services exit. 
+ */
+public class TestDataNodeExit {
+  private static int BASEPORT = 9923;
+  private static long WAIT_TIME_IN_MILLIS = 10;
+  Configuration conf;
+  MiniDFSCluster cluster = null;
+  
+  @Before
+  public void setUp() throws IOException {
+    conf = new HdfsConfiguration();
+    conf.setInt(DFSConfigKeys.DFS_BLOCK_SIZE_KEY, 100);
+    conf.setInt(DFSConfigKeys.DFS_BYTES_PER_CHECKSUM_KEY, 100);
+    cluster = new MiniDFSCluster.Builder(conf).numNameNodes(3)
+        .nameNodePort(BASEPORT).build();
+    for (int i = 0; i < 3; i++) {
+      cluster.waitActive(i);
+    }
+  }
+
+  @After
+  public void tearDown() throws Exception {
+    if (cluster != null)
+      cluster.shutdown();
+  }
+  
+  private void stopBPServiceThreads(int numStopThreads, DataNode dn)
+      throws Exception {
+    BPOfferService[] bpoList = dn.getAllBpOs();
+    int expected = dn.getBpOsCount() - numStopThreads;
+    int index = numStopThreads - 1;
+    while (index >= 0) {
+      bpoList[index--].stop();
+    }
+    int iterations = 3000; // Total 30 seconds MAX wait time
+    while(dn.getBpOsCount() != expected && iterations > 0) {
+      Thread.sleep(WAIT_TIME_IN_MILLIS);
+      iterations--;
+    }
+    assertEquals("Mismatch in number of BPServices running", expected,
+        dn.getBpOsCount());
+  }
+
+  /**
+   * Test BPService Thread Exit
+   */
+  @Test
+  public void testBPServiceExit() throws Exception {
+    DataNode dn = cluster.getDataNodes().get(0);
+    stopBPServiceThreads(1, dn);
+    assertTrue("DataNode should not exit", dn.isDatanodeUp());
+    stopBPServiceThreads(2, dn);
+    assertFalse("DataNode should exit", dn.isDatanodeUp());
+  }
+}