diff --git a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.HDFS-1623.txt b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.HDFS-1623.txt
index 7a4ef27f195..45169c41aec 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.HDFS-1623.txt
+++ b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.HDFS-1623.txt
@@ -151,3 +151,5 @@ HDFS-2742. HA: observed dataloss in replication stress test. (todd via eli)
 HDFS-2870. Fix log level for block debug info in processMisReplicatedBlocks (todd)
 
 HDFS-2859. LOCAL_ADDRESS_MATCHER.match has NPE when called from DFSUtil.getSuffixIDs when the host is incorrect (Bikas Saha via todd)
+
+HDFS-2861. checkpointing should verify that the dfs.http.address has been configured to a non-loopback for peer NN (todd)
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSUtil.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSUtil.java
index c9ccf9f38c7..31280675544 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSUtil.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSUtil.java
@@ -676,6 +676,33 @@ public static String getInfoServer(
     return getSuffixedConf(conf, httpAddressKey, httpAddressDefault, suffixes);
   }
   
+
+  /**
+   * Substitute a default host in the case that an address has been configured
+   * with a wildcard. This is used, for example, when determining the HTTP
+   * address of the NN -- if it's configured to bind to 0.0.0.0, we want to
+   * substitute the hostname from the filesystem URI rather than trying to
+   * connect to 0.0.0.0.
+   * @param configuredAddress the address found in the configuration
+   * @param defaultHost the host to substitute with, if configuredAddress
+   * is a local/wildcard address.
+   * @return the substituted address
+   * @throws IOException if it is a wildcard address and security is enabled
+   */
+  public static String substituteForWildcardAddress(String configuredAddress,
+      String defaultHost) throws IOException {
+    InetSocketAddress sockAddr = NetUtils.createSocketAddr(configuredAddress);
+    if (sockAddr.getAddress().isAnyLocalAddress()) {
+      if(UserGroupInformation.isSecurityEnabled()) {
+        throw new IOException("Cannot use a wildcard address with security. " +
+                              "Must explicitly set bind address for Kerberos");
+      }
+      return defaultHost + ":" + sockAddr.getPort();
+    } else {
+      return configuredAddress;
+    }
+  }
+  
   private static String getSuffixedConf(Configuration conf,
       String key, String defaultVal, String[] suffixes) {
     String ret = conf.get(DFSUtil.addKeySuffixes(key, suffixes));
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/HAUtil.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/HAUtil.java
index f12cd5e0bce..88122b9d8f8 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/HAUtil.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/HAUtil.java
@@ -129,16 +129,28 @@ public static Configuration getConfForOtherNode(
       Configuration myConf) {
     
     String nsId = DFSUtil.getNamenodeNameServiceId(myConf);
+    Preconditions.checkArgument(nsId != null,
+        "Could not determine namespace id. Please ensure that this " +
+        "machine is one of the machines listed as a NN RPC address, " +
+        "or configure " + DFSConfigKeys.DFS_FEDERATION_NAMESERVICE_ID);
+    
     Collection<String> nnIds = DFSUtil.getNameNodeIds(myConf, nsId);
     String myNNId = myConf.get(DFSConfigKeys.DFS_HA_NAMENODE_ID_KEY);
     Preconditions.checkArgument(nnIds != null,
-        "Could not determine namenode ids in namespace '%s'",
+        "Could not determine namenode ids in namespace '%s'. " +
+        "Please configure " +
+        DFSUtil.addKeySuffixes(DFSConfigKeys.DFS_HA_NAMENODES_KEY,
+            nsId),
         nsId);
     Preconditions.checkArgument(nnIds.size() == 2,
-        "Expected exactly 2 NameNodes in this namespace. Instead, got: '%s'",
-        Joiner.on("','").join(nnIds));
+        "Expected exactly 2 NameNodes in namespace '%s'. " +
+        "Instead, got only %s (NN ids were '%s'",
+        nsId, nnIds.size(), Joiner.on("','").join(nnIds));
     Preconditions.checkState(myNNId != null && !myNNId.isEmpty(),
-        "Could not determine own NN ID");
+        "Could not determine own NN ID in namespace '%s'. Please " +
+        "ensure that this node is one of the machines listed as an " +
+        "NN RPC address, or configure " + DFSConfigKeys.DFS_HA_NAMENODE_ID_KEY,
+        nsId);
 
     ArrayList<String> nnSet = Lists.newArrayList(nnIds);
     nnSet.remove(myNNId);
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSNamesystem.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSNamesystem.java
index bede75ebde5..b49005ff144 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSNamesystem.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSNamesystem.java
@@ -567,10 +567,14 @@ void stopActiveServices() {
       if (leaseManager != null) {
         leaseManager.stopMonitor();
       }
-      dir.fsImage.editLog.close();
-      // Update the fsimage with the last txid that we wrote
-      // so that the tailer starts from the right spot.
-      dir.fsImage.updateLastAppliedTxIdFromWritten();
+      if (dir != null && dir.fsImage != null) {
+        if (dir.fsImage.editLog != null) {
+          dir.fsImage.editLog.close();
+        }
+        // Update the fsimage with the last txid that we wrote
+        // so that the tailer starts from the right spot.
+        dir.fsImage.updateLastAppliedTxIdFromWritten();
+      }
     } finally {
       writeUnlock();
     }
@@ -612,7 +616,9 @@ void stopStandbyServices() throws IOException {
     if (editLogTailer != null) {
       editLogTailer.stop();
     }
-    dir.fsImage.editLog.close();
+    if (dir != null && dir.fsImage != null && dir.fsImage.editLog != null) {
+      dir.fsImage.editLog.close();
+    }
   }
   
   
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/SecondaryNameNode.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/SecondaryNameNode.java
index 2aebb63bd0e..8069501e01f 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/SecondaryNameNode.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/SecondaryNameNode.java
@@ -450,19 +450,10 @@ private String getInfoServer() throws IOException {
     }
 
     String configuredAddress = DFSUtil.getInfoServer(null, conf, true);
-    InetSocketAddress sockAddr = NetUtils.createSocketAddr(configuredAddress);
-    if (sockAddr.getAddress().isAnyLocalAddress()) {
-      if(UserGroupInformation.isSecurityEnabled()) {
-        throw new IOException("Cannot use a wildcard address with security. " +
-                              "Must explicitly set bind address for Kerberos");
-      }
-      return fsName.getHost() + ":" + sockAddr.getPort();
-    } else {
-      if(LOG.isDebugEnabled()) {
-        LOG.debug("configuredAddress = " + configuredAddress);
-      }
-      return configuredAddress;
-    }
+    String address = DFSUtil.substituteForWildcardAddress(configuredAddress,
+        fsName.getHost());
+    LOG.debug("Will connect to NameNode at HTTP address: " + address);
+    return address;
   }
   
   /**
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/StandbyCheckpointer.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/StandbyCheckpointer.java
index 83e85f7709c..9c5a3e5cd2b 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/StandbyCheckpointer.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/StandbyCheckpointer.java
@@ -31,6 +31,7 @@
 import org.apache.hadoop.hdfs.server.namenode.CheckpointConf;
 import org.apache.hadoop.hdfs.server.namenode.FSImage;
 import org.apache.hadoop.hdfs.server.namenode.FSNamesystem;
+import org.apache.hadoop.hdfs.server.namenode.NameNode;
 import org.apache.hadoop.hdfs.server.namenode.SaveNamespaceCancelledException;
 import org.apache.hadoop.hdfs.server.namenode.TransferFsImage;
 import org.apache.hadoop.net.NetUtils;
@@ -75,12 +76,11 @@ public StandbyCheckpointer(Configuration conf, FSNamesystem ns) {
    */
   private void setNameNodeAddresses(Configuration conf) {
     // Look up our own address.
-    String myAddrString = DFSUtil.getInfoServer(null, conf, true);
+    String myAddrString = getHttpAddress(conf);
 
     // Look up the active node's address
     Configuration confForActive = HAUtil.getConfForOtherNode(conf);
-    activeNNAddress = DFSUtil.getInfoServer(null, confForActive, true);
-    
+    activeNNAddress = getHttpAddress(confForActive);
     
     // Sanity-check.
     Preconditions.checkArgument(checkAddress(activeNNAddress),
@@ -90,13 +90,28 @@ private void setNameNodeAddresses(Configuration conf) {
     myNNAddress = NetUtils.createSocketAddr(myAddrString);
   }
   
+  private String getHttpAddress(Configuration conf) {
+    String configuredAddr = DFSUtil.getInfoServer(null, conf, true);
+    
+    // Use the hostname from the RPC address as a default, in case
+    // the HTTP address is configured to 0.0.0.0.
+    String hostnameFromRpc = NameNode.getServiceAddress(
+        conf, true).getHostName();
+    try {
+      return DFSUtil.substituteForWildcardAddress(
+          configuredAddr, hostnameFromRpc);
+    } catch (IOException e) {
+      throw new IllegalArgumentException(e);
+    }
+  }
+  
   /**
    * Ensure that the given address is valid and has a port
    * specified.
    */
   private boolean checkAddress(String addrStr) {
     InetSocketAddress addr = NetUtils.createSocketAddr(addrStr);
-    return addr.getPort() != 0;
+    return addr.getPort() != 0 && !addr.getAddress().isAnyLocalAddress();
   }
 
   public void start() {
@@ -287,4 +302,9 @@ private void doWork() {
       }
     }
   }
+
+  @VisibleForTesting
+  String getActiveNNAddress() {
+    return activeNNAddress;
+  }
 }
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/MiniDFSCluster.java b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/MiniDFSCluster.java
index dc3074aeb51..0173f46814d 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/MiniDFSCluster.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/MiniDFSCluster.java
@@ -586,13 +586,13 @@ private void createNameNodesAndSetConf(MiniDFSNNTopology nnTopology,
       conf.set(FS_DEFAULT_NAME_KEY, "127.0.0.1:" + onlyNN.getIpcPort());
     }
     
-    // If we have more than one nameservice, need to enumerate them in the
-    // config.
-    if (federation) {      
-      List<String> allNsIds = Lists.newArrayList();
-      for (MiniDFSNNTopology.NSConf nameservice : nnTopology.getNameservices()) {
+    List<String> allNsIds = Lists.newArrayList();
+    for (MiniDFSNNTopology.NSConf nameservice : nnTopology.getNameservices()) {
+      if (nameservice.getId() != null) {
         allNsIds.add(nameservice.getId());
       }
+    }
+    if (!allNsIds.isEmpty()) {
       conf.set(DFS_FEDERATION_NAMESERVICES, Joiner.on(",").join(allNsIds));
     }
     
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/MiniDFSNNTopology.java b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/MiniDFSNNTopology.java
index 311e687526b..4dfbfd81d95 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/MiniDFSNNTopology.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/MiniDFSNNTopology.java
@@ -57,7 +57,7 @@ public static MiniDFSNNTopology simpleSingleNN(
    */
   public static MiniDFSNNTopology simpleHATopology() {
     return new MiniDFSNNTopology()
-      .addNameservice(new MiniDFSNNTopology.NSConf(null)
+      .addNameservice(new MiniDFSNNTopology.NSConf("minidfs-ns")
         .addNN(new MiniDFSNNTopology.NNConf("nn1"))
         .addNN(new MiniDFSNNTopology.NNConf("nn2")));
   }
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDFSUtil.java b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDFSUtil.java
index 9773a50d54a..d3ea10f87ed 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDFSUtil.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDFSUtil.java
@@ -18,6 +18,7 @@
 
 package org.apache.hadoop.hdfs;
 
+import org.junit.Before;
 import org.junit.Test;
 
 import static org.junit.Assert.*;
@@ -43,6 +44,15 @@
 import static org.apache.hadoop.hdfs.DFSConfigKeys.*;
 
 public class TestDFSUtil {
+  
+  /**
+   * Reset to default UGI settings since some tests change them.
+   */
+  @Before
+  public void resetUGI() {
+    UserGroupInformation.setConfiguration(new Configuration());
+  }
+  
   /**
    * Test conversion of LocatedBlock to BlockLocation
    */
@@ -398,4 +408,11 @@ public void testHANameNodesWithFederation() {
     assertEquals(NS2_NN2_HOST, map.get("ns2").get("ns2-nn2").toString());
   }
 
+  @Test
+  public void testSubstituteForWildcardAddress() throws IOException {
+    assertEquals("foo:12345",
+        DFSUtil.substituteForWildcardAddress("0.0.0.0:12345", "foo"));
+    assertEquals("127.0.0.1:12345",
+        DFSUtil.substituteForWildcardAddress("127.0.0.1:12345", "foo"));
+  }
 }
\ No newline at end of file
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/ha/TestEditLogTailer.java b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/ha/TestEditLogTailer.java
index 1f5822ee575..bc5c487a766 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/ha/TestEditLogTailer.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/ha/TestEditLogTailer.java
@@ -125,7 +125,7 @@ private static void testStandbyTriggersLogRolls(int activeIndex)
     
     // Have to specify IPC ports so the NNs can talk to each other.
     MiniDFSNNTopology topology = new MiniDFSNNTopology()
-      .addNameservice(new MiniDFSNNTopology.NSConf(null)
+      .addNameservice(new MiniDFSNNTopology.NSConf("ns1")
         .addNN(new MiniDFSNNTopology.NNConf("nn1").setIpcPort(10001))
         .addNN(new MiniDFSNNTopology.NNConf("nn2").setIpcPort(10002)));
 
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/ha/TestFailureToReadEdits.java b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/ha/TestFailureToReadEdits.java
index e41a7a6e51b..7bc2d8e1645 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/ha/TestFailureToReadEdits.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/ha/TestFailureToReadEdits.java
@@ -82,7 +82,7 @@ public void setUpCluster() throws Exception {
     HAUtil.setAllowStandbyReads(conf, true);
     
     MiniDFSNNTopology topology = new MiniDFSNNTopology()
-      .addNameservice(new MiniDFSNNTopology.NSConf(null)
+      .addNameservice(new MiniDFSNNTopology.NSConf("ns1")
         .addNN(new MiniDFSNNTopology.NNConf("nn1").setHttpPort(10001))
         .addNN(new MiniDFSNNTopology.NNConf("nn2").setHttpPort(10002)));
     cluster = new MiniDFSCluster.Builder(conf)
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/ha/TestHAConfiguration.java b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/ha/TestHAConfiguration.java
new file mode 100644
index 00000000000..89d7ddd084f
--- /dev/null
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/ha/TestHAConfiguration.java
@@ -0,0 +1,81 @@
+/**
+ * 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.ha;
+
+import static org.junit.Assert.*;
+import static org.junit.Assert.assertEquals;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.hdfs.DFSConfigKeys;
+import org.apache.hadoop.hdfs.DFSUtil;
+import org.apache.hadoop.hdfs.server.namenode.FSNamesystem;
+import org.apache.hadoop.hdfs.server.namenode.NameNode;
+import org.apache.hadoop.test.GenericTestUtils;
+import org.junit.Test;
+import org.mockito.Mockito;
+
+/**
+ * Test cases that the HA configuration is reasonably validated and
+ * interpreted in various places. These should be proper unit tests
+ * which don't start daemons.
+ */
+public class TestHAConfiguration {
+  private static final String NSID = "ns1";
+  private static String HOST_A = "1.2.3.1";
+  private static String HOST_B = "1.2.3.2";
+
+  private FSNamesystem fsn = Mockito.mock(FSNamesystem.class);
+  private Configuration conf = new Configuration();
+
+  @Test
+  public void testCheckpointerValidityChecks() throws Exception {
+    try {
+      new StandbyCheckpointer(conf, fsn);
+      fail("Bad config did not throw an error");
+    } catch (IllegalArgumentException iae) {
+      GenericTestUtils.assertExceptionContains(
+          "Invalid URI for NameNode address", iae);
+    }
+  }
+  
+  @Test
+  public void testGetOtherNNHttpAddress() {
+    conf.set(DFSConfigKeys.DFS_FEDERATION_NAMESERVICES, NSID);    
+    conf.set(DFSConfigKeys.DFS_FEDERATION_NAMESERVICE_ID, NSID);
+    conf.set(DFSUtil.addKeySuffixes(
+        DFSConfigKeys.DFS_HA_NAMENODES_KEY, NSID),
+        "nn1,nn2");    
+    conf.set(DFSConfigKeys.DFS_HA_NAMENODE_ID_KEY, "nn1");
+    conf.set(DFSUtil.addKeySuffixes(
+            DFSConfigKeys.DFS_NAMENODE_RPC_ADDRESS_KEY,
+            NSID, "nn1"),
+        HOST_A + ":12345");
+    conf.set(DFSUtil.addKeySuffixes(
+            DFSConfigKeys.DFS_NAMENODE_RPC_ADDRESS_KEY,
+            NSID, "nn2"),
+        HOST_B + ":12345");
+    NameNode.initializeGenericKeys(conf, NSID, "nn1");
+
+    // Since we didn't configure the HTTP address, and the default is
+    // 0.0.0.0, it should substitute the address from the RPC configuratoin
+    // above.
+    StandbyCheckpointer checkpointer = new StandbyCheckpointer(conf, fsn);
+    assertEquals(HOST_B + ":" + DFSConfigKeys.DFS_NAMENODE_HTTP_PORT_DEFAULT,
+        checkpointer.getActiveNNAddress());
+  }
+}
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/ha/TestStandbyCheckpoints.java b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/ha/TestStandbyCheckpoints.java
index 2c0c81947c8..a34d6bdfc21 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/ha/TestStandbyCheckpoints.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/ha/TestStandbyCheckpoints.java
@@ -60,7 +60,7 @@ public void setupCluster() throws Exception {
     conf.setInt(DFSConfigKeys.DFS_HA_TAILEDITS_PERIOD_KEY, 1);
 
     MiniDFSNNTopology topology = new MiniDFSNNTopology()
-      .addNameservice(new MiniDFSNNTopology.NSConf(null)
+      .addNameservice(new MiniDFSNNTopology.NSConf("ns1")
         .addNN(new MiniDFSNNTopology.NNConf("nn1").setHttpPort(10001))
         .addNN(new MiniDFSNNTopology.NNConf("nn2").setHttpPort(10002)));