HDFS-6995. Block should be placed in the client's 'rack-local' node if 'client-local' node is not available (vinayakumarb)

Adding missed test file

(cherry picked from commit cba1f9e389)
(cherry picked from commit fea721daf9)

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/TestDefaultBlockPlacementPolicy.java

@@ -0,0 +1,131 @@
+/**
+ * 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.namenode;
+
+import static org.junit.Assert.*;
+
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.util.EnumSet;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.CreateFlag;
+import org.apache.hadoop.fs.FileAlreadyExistsException;
+import org.apache.hadoop.fs.ParentNotDirectoryException;
+import org.apache.hadoop.fs.UnresolvedLinkException;
+import org.apache.hadoop.fs.permission.FsPermission;
+import org.apache.hadoop.fs.permission.PermissionStatus;
+import org.apache.hadoop.hdfs.DFSConfigKeys;
+import org.apache.hadoop.hdfs.HdfsConfiguration;
+import org.apache.hadoop.hdfs.MiniDFSCluster;
+import org.apache.hadoop.hdfs.protocol.HdfsFileStatus;
+import org.apache.hadoop.hdfs.protocol.LocatedBlock;
+import org.apache.hadoop.hdfs.server.protocol.NamenodeProtocols;
+import org.apache.hadoop.net.StaticMapping;
+import org.apache.hadoop.security.AccessControlException;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+public class TestDefaultBlockPlacementPolicy {
+
+  private Configuration conf;
+  private final short REPLICATION_FACTOR = (short) 3;
+  private final int DEFAULT_BLOCK_SIZE = 1024;
+  private MiniDFSCluster cluster = null;
+  private NamenodeProtocols nameNodeRpc = null;
+  private FSNamesystem namesystem = null;
+  private PermissionStatus perm = null;
+
+  @Before
+  public void setup() throws IOException {
+    StaticMapping.resetMap();
+    conf = new HdfsConfiguration();
+    final String[] racks = { "/RACK0", "/RACK0", "/RACK2", "/RACK3", "/RACK2" };
+    final String[] hosts = { "/host0", "/host1", "/host2", "/host3", "/host4" };
+
+    conf.setLong(DFSConfigKeys.DFS_BLOCK_SIZE_KEY, DEFAULT_BLOCK_SIZE);
+    conf.setInt(DFSConfigKeys.DFS_BYTES_PER_CHECKSUM_KEY,
+        DEFAULT_BLOCK_SIZE / 2);
+    cluster = new MiniDFSCluster.Builder(conf).numDataNodes(5).racks(racks)
+        .hosts(hosts).build();
+    cluster.waitActive();
+    nameNodeRpc = cluster.getNameNodeRpc();
+    namesystem = cluster.getNamesystem();
+    perm = new PermissionStatus("TestDefaultBlockPlacementPolicy", null,
+        FsPermission.getDefault());
+  }
+
+  @After
+  public void teardown() {
+    if (cluster != null) {
+      cluster.shutdown();
+    }
+  }
+
+  /**
+   * Verify rack-local node selection for the rack-local client in case of no
+   * local node
+   */
+  @Test
+  public void testLocalRackPlacement() throws Exception {
+    String clientMachine = "client.foo.com";
+    // Map client to RACK2
+    String clientRack = "/RACK2";
+    StaticMapping.addNodeToRack(clientMachine, clientRack);
+    testPlacement(clientMachine, clientRack);
+  }
+
+  /**
+   * Verify Random rack node selection for remote client
+   */
+  @Test
+  public void testRandomRackSelectionForRemoteClient() throws Exception {
+    String clientMachine = "client.foo.com";
+    // Don't map client machine to any rack,
+    // so by default it will be treated as /default-rack
+    // in that case a random node should be selected as first node.
+    testPlacement(clientMachine, null);
+  }
+
+  private void testPlacement(String clientMachine,
+      String clientRack) throws AccessControlException,
+      SafeModeException, FileAlreadyExistsException, UnresolvedLinkException,
+      FileNotFoundException, ParentNotDirectoryException, IOException,
+      NotReplicatedYetException {
+    // write 5 files and check whether all times block placed
+    for (int i = 0; i < 5; i++) {
+      String src = "/test-" + i;
+      // Create the file with client machine
+      HdfsFileStatus fileStatus = namesystem.startFile(src, perm,
+          clientMachine, clientMachine, EnumSet.of(CreateFlag.CREATE), true,
+          REPLICATION_FACTOR, DEFAULT_BLOCK_SIZE, null);
+      LocatedBlock locatedBlock = nameNodeRpc.addBlock(src, clientMachine,
+          null, null, fileStatus.getFileId(), null);
+
+      assertEquals("Block should be allocated sufficient locations",
+          REPLICATION_FACTOR, locatedBlock.getLocations().length);
+      if (clientRack != null) {
+        assertEquals("First datanode should be rack local", clientRack,
+            locatedBlock.getLocations()[0].getNetworkLocation());
+      }
+      nameNodeRpc.abandonBlock(locatedBlock.getBlock(), fileStatus.getFileId(),
+          src, clientMachine);
+    }
+  }
+}