HDFS-5454. Merge r1551296 from trunk to branch-2.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1556083 13f79535-47bb-0310-9956-ffa450edef68

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -380,6 +380,9 @@ BREAKDOWN OF HDFS-2832 SUBTASKS AND RELATED JIRAS
 
     HDFS-5648. Get rid of FsDatasetImpl#perVolumeReplicaMap. (Arpit Agarwal)
 
+    HDFS-5454. DataNode UUID should be assigned prior to FsDataset
+    initialization. (Arpit Agarwal)
+
 Release 2.3.0 - UNRELEASED
 
   INCOMPATIBLE CHANGES

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNode.java

@@ -791,8 +791,6 @@ public class DataNode extends Configured
       storageInfo = new StorageInfo(nsInfo);
     }
 
-    checkDatanodeUuid();
-
     DatanodeID dnId = new DatanodeID(
         streamingAddr.getAddress().getHostAddress(), hostName, 
         storage.getDatanodeUuid(), getXferPort(), getInfoPort(),
@@ -941,6 +939,9 @@ public class DataNode extends Configured
           + ";nsInfo=" + nsInfo + ";dnuuid=" + storage.getDatanodeUuid());
     }
 
+    // If this is a newly formatted DataNode then assign a new DatanodeUuid.
+    checkDatanodeUuid();
+
     synchronized(this)  {
       if (data == null) {
         data = factory.newInstance(this, storage, conf);

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/TestDataNodeInitStorage.java

@@ -0,0 +1,87 @@
+/**
+ * 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 java.io.*;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+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.fsdataset.FsDatasetSpi;
+import org.junit.Test;
+
+import static org.hamcrest.core.IsNot.not;
+import static org.junit.Assert.*;
+
+
+/**
+ * Test to verify that the DataNode Uuid is correctly initialized before
+ * FsDataSet initialization.
+ */
+public class TestDataNodeInitStorage {
+  public static final Log LOG = LogFactory.getLog(TestDataNodeInitStorage.class);
+
+  static private class SimulatedFsDatasetVerifier extends SimulatedFSDataset {
+    static class Factory extends FsDatasetSpi.Factory<SimulatedFSDataset> {
+      @Override
+      public SimulatedFsDatasetVerifier newInstance(
+          DataNode datanode, DataStorage storage,
+          Configuration conf) throws IOException {
+        return new SimulatedFsDatasetVerifier(storage, conf);
+      }
+
+      @Override
+      public boolean isSimulated() {
+        return true;
+      }
+    }
+
+    public static void setFactory(Configuration conf) {
+      conf.set(DFSConfigKeys.DFS_DATANODE_FSDATASET_FACTORY_KEY,
+               Factory.class.getName());
+    }
+
+    // This constructor does the actual verification by ensuring that
+    // the DatanodeUuid is initialized.
+    public SimulatedFsDatasetVerifier(DataStorage storage, Configuration conf) {
+      super(storage, conf);
+      LOG.info("Assigned DatanodeUuid is " + storage.getDatanodeUuid());
+      assert(storage.getDatanodeUuid() != null);
+      assert(storage.getDatanodeUuid().length() != 0);
+    }
+  }
+
+
+  @Test (timeout = 60000)
+  public void testDataNodeInitStorage() throws Throwable {
+    // Create configuration to use SimulatedFsDatasetVerifier#Factory.
+    Configuration conf = new HdfsConfiguration();
+    SimulatedFsDatasetVerifier.setFactory(conf);
+
+    // Start a cluster so that SimulatedFsDatasetVerifier constructor is
+    // invoked.
+    MiniDFSCluster cluster =
+        new MiniDFSCluster.Builder(conf).numDataNodes(1).build();
+    cluster.waitActive();
+    cluster.shutdown();
+  }
+}