HDFS-8582. Support getting a list of reconfigurable config properties and do not generate spurious reconfig warnings (Lei (Eddy) Xu via Colin P. McCabe)

(cherry picked from commit d112d183242f447d4b742139f3a4ea531a997f45)

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/conf/ReconfigurableBase.java

@@ -88,6 +88,11 @@ public abstract class ReconfigurableBase
     reconfigurationUtil = Preconditions.checkNotNull(ru);
   }
 
+  /**
+   * Create a new configuration.
+   */
+  protected abstract Configuration getNewConf();
+
   @VisibleForTesting
   public Collection<PropertyChange> getChangedProperties(
       Configuration newConf, Configuration oldConf) {
@@ -108,17 +113,16 @@ public abstract class ReconfigurableBase
     public void run() {
       LOG.info("Starting reconfiguration task.");
       Configuration oldConf = this.parent.getConf();
-      Configuration newConf = new Configuration();
+      Configuration newConf = this.parent.getNewConf();
       Collection<PropertyChange> changes =
           this.parent.getChangedProperties(newConf, oldConf);
       Map<PropertyChange, Optional<String>> results = Maps.newHashMap();
       for (PropertyChange change : changes) {
         String errorMessage = null;
         if (!this.parent.isPropertyReconfigurable(change.prop)) {
-          errorMessage = "Property " + change.prop +
-              " is not reconfigurable";
-          LOG.info(errorMessage);
-          results.put(change, Optional.of(errorMessage));
+          LOG.info(String.format(
+              "Property %s is not configurable: old value: %s, new value: %s",
+              change.prop, change.oldVal, change.newVal));
           continue;
         }
         LOG.info("Change property: " + change.prop + " from \""

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/conf/TestReconfiguration.java

@@ -118,6 +118,11 @@ public class TestReconfiguration {
       super(conf);
     }
 
+    @Override
+    protected Configuration getNewConf() {
+      return new Configuration();
+    }
+
     @Override 
     public Collection<String> getReconfigurableProperties() {
       return Arrays.asList(PROP1, PROP2, PROP4);
@@ -336,6 +341,11 @@ public class TestReconfiguration {
       super(conf);
     }
 
+    @Override
+    protected Configuration getNewConf() {
+      return new Configuration();
+    }
+
     final CountDownLatch latch = new CountDownLatch(1);
 
     @Override
@@ -397,7 +407,7 @@ public class TestReconfiguration {
 
     waitAsyncReconfigureTaskFinish(dummy);
     ReconfigurationTaskStatus status = dummy.getReconfigurationTaskStatus();
-    assertEquals(3, status.getStatus().size());
+    assertEquals(2, status.getStatus().size());
     for (Map.Entry<PropertyChange, Optional<String>> result :
         status.getStatus().entrySet()) {
       PropertyChange change = result.getKey();

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

@@ -312,6 +312,10 @@ Release 2.8.0 - UNRELEASED
     HDFS-8605. Merge Refactor of DFSOutputStream from HDFS-7285 branch.
     (vinayakumarb via wang)
 
+    HDFS-8582. Support getting a list of reconfigurable config properties and
+    do not generate spurious reconfig warnings (Lei (Eddy) Xu via Colin P.
+    McCabe)
+
   OPTIMIZATIONS
 
     HDFS-8026. Trace FSOutputSummer#writeChecksumChunks rather than

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocol/ClientDatanodeProtocol.java

@@ -160,6 +160,11 @@ public interface ClientDatanodeProtocol {
    */
   ReconfigurationTaskStatus getReconfigurationStatus() throws IOException;
 
+  /**
+   * Get a list of allowed properties for reconfiguration.
+   */
+  List<String> listReconfigurableProperties() throws IOException;
+
   /**
    * Trigger a new block report.
    */

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocolPB/ClientDatanodeProtocolServerSideTranslatorPB.java

@@ -44,6 +44,8 @@ import org.apache.hadoop.hdfs.protocol.proto.ClientDatanodeProtocolProtos.GetHdf
 import org.apache.hadoop.hdfs.protocol.proto.ClientDatanodeProtocolProtos.GetHdfsBlockLocationsResponseProto.Builder;
 import org.apache.hadoop.hdfs.protocol.proto.ClientDatanodeProtocolProtos.GetReplicaVisibleLengthRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientDatanodeProtocolProtos.GetReplicaVisibleLengthResponseProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientDatanodeProtocolProtos.ListReconfigurablePropertiesRequestProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientDatanodeProtocolProtos.ListReconfigurablePropertiesResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientDatanodeProtocolProtos.RefreshNamenodesRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientDatanodeProtocolProtos.RefreshNamenodesResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientDatanodeProtocolProtos.ShutdownDatanodeRequestProto;
@@ -208,6 +210,23 @@ public class ClientDatanodeProtocolServerSideTranslatorPB implements
     return START_RECONFIG_RESP;
   }
 
+  @Override
+  public ListReconfigurablePropertiesResponseProto listReconfigurableProperties(
+        RpcController controller,
+        ListReconfigurablePropertiesRequestProto request)
+      throws ServiceException {
+    ListReconfigurablePropertiesResponseProto.Builder builder =
+        ListReconfigurablePropertiesResponseProto.newBuilder();
+    try {
+      for (String name : impl.listReconfigurableProperties()) {
+        builder.addName(name);
+      }
+    } catch (IOException e) {
+      throw new ServiceException(e);
+    }
+    return builder.build();
+  }
+
   @Override
   public GetReconfigurationStatusResponseProto getReconfigurationStatus(
       RpcController unused, GetReconfigurationStatusRequestProto request)

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocolPB/ClientDatanodeProtocolTranslatorPB.java

@@ -52,6 +52,8 @@ import org.apache.hadoop.hdfs.protocol.proto.ClientDatanodeProtocolProtos.GetDat
 import org.apache.hadoop.hdfs.protocol.proto.ClientDatanodeProtocolProtos.GetHdfsBlockLocationsRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientDatanodeProtocolProtos.GetHdfsBlockLocationsResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientDatanodeProtocolProtos.GetReplicaVisibleLengthRequestProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientDatanodeProtocolProtos.ListReconfigurablePropertiesRequestProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientDatanodeProtocolProtos.ListReconfigurablePropertiesResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientDatanodeProtocolProtos.RefreshNamenodesRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientDatanodeProtocolProtos.GetReconfigurationStatusRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientDatanodeProtocolProtos.GetReconfigurationStatusResponseProto;
@@ -59,7 +61,6 @@ import org.apache.hadoop.hdfs.protocol.proto.ClientDatanodeProtocolProtos.GetRec
 import org.apache.hadoop.hdfs.protocol.proto.ClientDatanodeProtocolProtos.ShutdownDatanodeRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientDatanodeProtocolProtos.StartReconfigurationRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientDatanodeProtocolProtos.TriggerBlockReportRequestProto;
-import org.apache.hadoop.hdfs.protocol.proto.ClientDatanodeProtocolProtos.TriggerBlockReportResponseProto;
 import org.apache.hadoop.hdfs.security.token.block.BlockTokenIdentifier;
 import org.apache.hadoop.ipc.ProtobufHelper;
 import org.apache.hadoop.ipc.ProtobufRpcEngine;
@@ -101,6 +102,9 @@ public class ClientDatanodeProtocolTranslatorPB implements
       GetReconfigurationStatusRequestProto.newBuilder().build();
   private final static StartReconfigurationRequestProto VOID_START_RECONFIG =
       StartReconfigurationRequestProto.newBuilder().build();
+  private static final ListReconfigurablePropertiesRequestProto
+      VOID_LIST_RECONFIGURABLE_PROPERTIES =
+      ListReconfigurablePropertiesRequestProto.newBuilder().build();
 
   public ClientDatanodeProtocolTranslatorPB(DatanodeID datanodeid,
       Configuration conf, int socketTimeout, boolean connectToDnViaHostname,
@@ -337,6 +341,19 @@ public class ClientDatanodeProtocolTranslatorPB implements
     return new ReconfigurationTaskStatus(startTime, endTime, statusMap);
   }
 
+  @Override
+  public List<String> listReconfigurableProperties()
+      throws IOException {
+    ListReconfigurablePropertiesResponseProto response;
+    try {
+      response = rpcProxy.listReconfigurableProperties(NULL_CONTROLLER,
+          VOID_LIST_RECONFIGURABLE_PROPERTIES);
+      return response.getNameList();
+    } catch (ServiceException e) {
+      throw ProtobufHelper.getRemoteException(e);
+    }
+  }
+
   @Override
   public void triggerBlockReport(BlockReportOptions options)
       throws IOException {

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

@@ -273,6 +273,11 @@ public class DataNode extends ReconfigurableBase
 
   static final int CURRENT_BLOCK_FORMAT_VERSION = 1;
 
+  /** A list of property that are reconfigurable at runtime. */
+  private static final List<String> RECONFIGURABLE_PROPERTIES =
+      Collections.unmodifiableList(
+          Arrays.asList(DFS_DATANODE_DATA_DIR_KEY));
+
   /**
    * Use {@link NetUtils#createSocketAddr(String)} instead.
    */
@@ -450,6 +455,11 @@ public class DataNode extends ReconfigurableBase
             });
   }
 
+  @Override  // ReconfigurableBase
+  protected Configuration getNewConf() {
+    return new HdfsConfiguration();
+  }
+
   @Override
   public void reconfigurePropertyImpl(String property, String newVal)
       throws ReconfigurationException {
@@ -470,11 +480,9 @@ public class DataNode extends ReconfigurableBase
   /**
    * Get a list of the keys of the re-configurable properties in configuration.
    */
-  @Override
+  @Override // Reconfigurable
   public Collection<String> getReconfigurableProperties() {
-    List<String> reconfigurable =
-        Collections.unmodifiableList(Arrays.asList(DFS_DATANODE_DATA_DIR_KEY));
-    return reconfigurable;
+    return RECONFIGURABLE_PROPERTIES;
   }
 
   /**
@@ -3052,6 +3060,12 @@ public class DataNode extends ReconfigurableBase
     return getReconfigurationTaskStatus();
   }
 
+  @Override // ClientDatanodeProtocol
+  public List<String> listReconfigurableProperties()
+      throws IOException {
+    return RECONFIGURABLE_PROPERTIES;
+  }
+
   @Override // ClientDatanodeProtocol
   public void triggerBlockReport(BlockReportOptions options)
       throws IOException {

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/tools/DFSAdmin.java

@@ -408,7 +408,7 @@ public class DFSAdmin extends FsShell {
     "\t[-refreshSuperUserGroupsConfiguration]\n" +
     "\t[-refreshCallQueue]\n" +
     "\t[-refresh <host:ipc_port> <key> [arg1..argn]\n" +
-    "\t[-reconfig <datanode|...> <host:ipc_port> <start|status>]\n" +
+    "\t[-reconfig <datanode|...> <host:ipc_port> <start|status|properties>]\n" +
     "\t[-printTopology]\n" +
     "\t[-refreshNamenodes datanode_host:ipc_port]\n"+
     "\t[-deleteBlockPool datanode_host:ipc_port blockpoolId [force]]\n"+
@@ -951,8 +951,9 @@ public class DFSAdmin extends FsShell {
 
     String refreshCallQueue = "-refreshCallQueue: Reload the call queue from config\n";
 
-    String reconfig = "-reconfig <datanode|...> <host:ipc_port> <start|status>:\n" +
-        "\tStarts reconfiguration or gets the status of an ongoing reconfiguration.\n" +
+    String reconfig = "-reconfig <datanode|...> <host:ipc_port> <start|status|properties>:\n" +
+        "\tStarts or gets the status of a reconfiguration operation, \n" +
+        "\tor gets a list of reconfigurable properties.\n" +
         "\tThe second parameter specifies the node type.\n" +
         "\tCurrently, only reloading DataNode's configuration is supported.\n";
 
@@ -1411,6 +1412,9 @@ public class DFSAdmin extends FsShell {
       return startReconfiguration(nodeType, address);
     } else if ("status".equals(op)) {
       return getReconfigurationStatus(nodeType, address, System.out, System.err);
+    } else if ("properties".equals(op)) {
+      return getReconfigurableProperties(
+          nodeType, address, System.out, System.err);
     }
     System.err.println("Unknown operation: " + op);
     return -1;
@@ -1448,18 +1452,24 @@ public class DFSAdmin extends FsShell {
 
         out.println(" and finished at " +
             new Date(status.getEndTime()).toString() + ".");
+        if (status.getStatus() == null) {
+          // Nothing to report.
+          return 0;
+        }
         for (Map.Entry<PropertyChange, Optional<String>> result :
             status.getStatus().entrySet()) {
           if (!result.getValue().isPresent()) {
-            out.print("SUCCESS: ");
+            out.printf(
+                "SUCCESS: Changed property %s%n\tFrom: \"%s\"%n\tTo: \"%s\"%n",
+                result.getKey().prop, result.getKey().oldVal,
+                result.getKey().newVal);
           } else {
-            out.print("FAILED: ");
-          }
-          out.printf("Change property %s%n\tFrom: \"%s\"%n\tTo: \"%s\"%n",
-              result.getKey().prop, result.getKey().oldVal,
-              result.getKey().newVal);
-          if (result.getValue().isPresent()) {
-            out.println("\tError: " + result.getValue().get() + ".");
+            final String errorMsg = result.getValue().get();
+            out.printf(
+                  "FAILED: Change property %s%n\tFrom: \"%s\"%n\tTo: \"%s\"%n",
+                  result.getKey().prop, result.getKey().oldVal,
+                  result.getKey().newVal);
+            out.println("\tError: " + errorMsg + ".");
           }
         }
       } catch (IOException e) {
@@ -1467,7 +1477,32 @@ public class DFSAdmin extends FsShell {
         return 1;
       }
     } else {
-      err.println("Node type " + nodeType + " does not support reconfiguration.");
+      err.println("Node type " + nodeType +
+          " does not support reconfiguration.");
+      return 1;
+    }
+    return 0;
+  }
+
+  int getReconfigurableProperties(String nodeType, String address,
+      PrintStream out, PrintStream err) throws IOException {
+    if ("datanode".equals(nodeType)) {
+      ClientDatanodeProtocol dnProxy = getDataNodeProxy(address);
+      try {
+        List<String> properties =
+            dnProxy.listReconfigurableProperties();
+        out.println(
+            "Configuration properties that are allowed to be reconfigured:");
+        for (String name : properties) {
+          out.println(name);
+        }
+      } catch (IOException e) {
+        err.println("DataNode reconfiguration: " + e + ".");
+        return 1;
+      }
+    } else {
+      err.println("Node type " + nodeType +
+          " does not support reconfiguration.");
       return 1;
     }
     return 0;

hadoop-hdfs-project/hadoop-hdfs/src/main/proto/ClientDatanodeProtocol.proto

@@ -180,6 +180,14 @@ message GetReconfigurationStatusResponseProto {
   repeated GetReconfigurationStatusConfigChangeProto changes = 3;
 }
 
+message ListReconfigurablePropertiesRequestProto {
+}
+
+/** Query the reconfigurable properties on DataNode. */
+message ListReconfigurablePropertiesResponseProto {
+  repeated string name = 1;
+}
+
 /**
  * Protocol used from client to the Datanode.
  * See the request and response for details of rpc call.
@@ -230,6 +238,10 @@ service ClientDatanodeProtocolService {
   rpc startReconfiguration(StartReconfigurationRequestProto)
       returns(StartReconfigurationResponseProto);
 
+  rpc listReconfigurableProperties(
+      ListReconfigurablePropertiesRequestProto)
+      returns(ListReconfigurablePropertiesResponseProto);
+
   rpc triggerBlockReport(TriggerBlockReportRequestProto)
       returns(TriggerBlockReportResponseProto);
 }

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/tools/TestDFSAdmin.java

@@ -22,6 +22,7 @@ import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_DATANODE_DATA_DIR_KEY;
 import com.google.common.collect.Lists;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.conf.ReconfigurationUtil;
+import org.apache.hadoop.hdfs.DFSConfigKeys;
 import org.apache.hadoop.hdfs.MiniDFSCluster;
 import org.apache.hadoop.hdfs.server.common.Storage;
 import org.apache.hadoop.hdfs.server.datanode.DataNode;
@@ -42,6 +43,7 @@ import static org.hamcrest.CoreMatchers.allOf;
 import static org.hamcrest.CoreMatchers.anyOf;
 import static org.hamcrest.CoreMatchers.is;
 import static org.hamcrest.CoreMatchers.not;
+import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertThat;
 import static org.junit.Assert.assertTrue;
 import static org.hamcrest.CoreMatchers.containsString;
@@ -50,18 +52,17 @@ import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
 
 public class TestDFSAdmin {
+  private Configuration conf = null;
   private MiniDFSCluster cluster;
   private DFSAdmin admin;
   private DataNode datanode;
 
   @Before
   public void setUp() throws Exception {
-    Configuration conf = new Configuration();
-    cluster = new MiniDFSCluster.Builder(conf).numDataNodes(1).build();
-    cluster.waitActive();
+    conf = new Configuration();
+    restartCluster();
 
     admin = new DFSAdmin();
-    datanode = cluster.getDataNodes().get(0);
   }
 
   @After
@@ -72,6 +73,15 @@ public class TestDFSAdmin {
     }
   }
 
+  private void restartCluster() throws IOException {
+    if (cluster != null) {
+      cluster.shutdown();
+    }
+    cluster = new MiniDFSCluster.Builder(conf).numDataNodes(1).build();
+    cluster.waitActive();
+    datanode = cluster.getDataNodes().get(0);
+  }
+
   private List<String> getReconfigureStatus(String nodeType, String address)
       throws IOException {
     ByteArrayOutputStream bufOut = new ByteArrayOutputStream();
@@ -87,16 +97,26 @@ public class TestDFSAdmin {
     return outputs;
   }
 
-  @Test(timeout = 30000)
-  public void testGetReconfigureStatus()
+  /**
+   * Test reconfiguration and check the status outputs.
+   * @param expectedSuccuss set true if the reconfiguration task should success.
+   * @throws IOException
+   * @throws InterruptedException
+   */
+  private void testGetReconfigurationStatus(boolean expectedSuccuss)
       throws IOException, InterruptedException {
     ReconfigurationUtil ru = mock(ReconfigurationUtil.class);
     datanode.setReconfigurationUtil(ru);
 
     List<ReconfigurationUtil.PropertyChange> changes =
-        new ArrayList<ReconfigurationUtil.PropertyChange>();
+        new ArrayList<>();
     File newDir = new File(cluster.getDataDirectory(), "data_new");
-    newDir.mkdirs();
+    if (expectedSuccuss) {
+      newDir.mkdirs();
+    } else {
+      // Inject failure.
+      newDir.createNewFile();
+    }
     changes.add(new ReconfigurationUtil.PropertyChange(
         DFS_DATANODE_DATA_DIR_KEY, newDir.toString(),
         datanode.getConf().get(DFS_DATANODE_DATA_DIR_KEY)));
@@ -121,31 +141,74 @@ public class TestDFSAdmin {
       Thread.sleep(100);
     }
     assertTrue(count > 0);
-    assertThat(outputs.size(), is(8));  // 3 (SUCCESS) + 4 (FAILED)
+    if (expectedSuccuss) {
+      assertThat(outputs.size(), is(4));
+    } else {
+      assertThat(outputs.size(), is(6));
+    }
 
     List<StorageLocation> locations = DataNode.getStorageLocations(
         datanode.getConf());
-    assertThat(locations.size(), is(1));
-    assertThat(locations.get(0).getFile(), is(newDir));
-    // Verify the directory is appropriately formatted.
-    assertTrue(new File(newDir, Storage.STORAGE_DIR_CURRENT).isDirectory());
-
-    int successOffset = outputs.get(1).startsWith("SUCCESS:") ? 1 : 5;
-    int failedOffset = outputs.get(1).startsWith("FAILED:") ? 1: 4;
-    assertThat(outputs.get(successOffset),
-        containsString("Change property " + DFS_DATANODE_DATA_DIR_KEY));
-    assertThat(outputs.get(successOffset + 1),
+    if (expectedSuccuss) {
+      assertThat(locations.size(), is(1));
+      assertThat(locations.get(0).getFile(), is(newDir));
+      // Verify the directory is appropriately formatted.
+      assertTrue(new File(newDir, Storage.STORAGE_DIR_CURRENT).isDirectory());
+    } else {
+      assertTrue(locations.isEmpty());
+    }
+
+    int offset = 1;
+    if (expectedSuccuss) {
+      assertThat(outputs.get(offset),
+          containsString("SUCCESS: Changed property " +
+              DFS_DATANODE_DATA_DIR_KEY));
+    } else {
+      assertThat(outputs.get(offset),
+          containsString("FAILED: Change property " +
+              DFS_DATANODE_DATA_DIR_KEY));
+    }
+    assertThat(outputs.get(offset + 1),
         is(allOf(containsString("From:"), containsString("data1"),
             containsString("data2"))));
-    assertThat(outputs.get(successOffset + 2),
+    assertThat(outputs.get(offset + 2),
         is(not(anyOf(containsString("data1"), containsString("data2")))));
-    assertThat(outputs.get(successOffset + 2),
+    assertThat(outputs.get(offset + 2),
         is(allOf(containsString("To"), containsString("data_new"))));
-    assertThat(outputs.get(failedOffset),
-        containsString("Change property randomKey"));
-    assertThat(outputs.get(failedOffset + 1),
-        containsString("From: \"old456\""));
-    assertThat(outputs.get(failedOffset + 2),
-        containsString("To: \"new123\""));
+  }
+
+  @Test(timeout = 30000)
+  public void testGetReconfigurationStatus()
+      throws IOException, InterruptedException {
+    testGetReconfigurationStatus(true);
+    restartCluster();
+    testGetReconfigurationStatus(false);
+  }
+
+  private List<String> getReconfigurationAllowedProperties(
+      String nodeType, String address)
+      throws IOException {
+    ByteArrayOutputStream bufOut = new ByteArrayOutputStream();
+    PrintStream out = new PrintStream(bufOut);
+    ByteArrayOutputStream bufErr = new ByteArrayOutputStream();
+    PrintStream err = new PrintStream(bufErr);
+    admin.getReconfigurableProperties(nodeType, address, out, err);
+    Scanner scanner = new Scanner(bufOut.toString());
+    List<String> outputs = Lists.newArrayList();
+    while (scanner.hasNextLine()) {
+      outputs.add(scanner.nextLine());
+    }
+    return outputs;
+  }
+
+  @Test(timeout = 30000)
+  public void testGetReconfigAllowedProperties() throws IOException {
+    final int port = datanode.getIpcPort();
+    final String address = "localhost:" + port;
+    List<String> outputs =
+        getReconfigurationAllowedProperties("datanode", address);
+    assertEquals(2, outputs.size());
+    assertEquals(DFSConfigKeys.DFS_DATANODE_DATA_DIR_KEY,
+        outputs.get(1));
   }
 }