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From a..@apache.org
Subject [11/46] hadoop git commit: HDFS-7390. Provide JMX metrics per storage type. (Benoy Antony)
Date Wed, 01 Jul 2015 21:09:57 GMT
HDFS-7390. Provide JMX metrics per storage type. (Benoy Antony)


Project: http://git-wip-us.apache.org/repos/asf/hadoop/repo
Commit: http://git-wip-us.apache.org/repos/asf/hadoop/commit/d3fed8e6
Tree: http://git-wip-us.apache.org/repos/asf/hadoop/tree/d3fed8e6
Diff: http://git-wip-us.apache.org/repos/asf/hadoop/diff/d3fed8e6

Branch: refs/heads/HDFS-7240
Commit: d3fed8e653ed9e18d3a29a11c4b24a628ac770bb
Parents: fde20ff
Author: Benoy Antony <benoy@apache.org>
Authored: Mon Jun 29 11:00:22 2015 -0700
Committer: Benoy Antony <benoy@apache.org>
Committed: Mon Jun 29 11:00:22 2015 -0700

----------------------------------------------------------------------
 .../server/blockmanagement/BlockManager.java    |  15 +-
 .../blockmanagement/BlockStatsMXBean.java       |  36 +++++
 .../blockmanagement/DatanodeStatistics.java     |   6 +
 .../blockmanagement/HeartbeatManager.java       |  96 +++++++++++-
 .../blockmanagement/StorageTypeStats.java       | 115 +++++++++++++++
 .../blockmanagement/TestBlockStatsMXBean.java   | 146 +++++++++++++++++++
 6 files changed, 412 insertions(+), 2 deletions(-)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/hadoop/blob/d3fed8e6/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockManager.java
----------------------------------------------------------------------
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockManager.java
b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockManager.java
index 5bd4980..0b60a97 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockManager.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockManager.java
@@ -39,6 +39,8 @@ import java.util.TreeSet;
 import java.util.concurrent.ThreadLocalRandom;
 import java.util.concurrent.atomic.AtomicLong;
 
+import javax.management.ObjectName;
+
 import org.apache.hadoop.HadoopIllegalArgumentException;
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.conf.Configuration;
@@ -85,6 +87,7 @@ import org.apache.hadoop.hdfs.server.protocol.KeyUpdateCommand;
 import org.apache.hadoop.hdfs.server.protocol.ReceivedDeletedBlockInfo;
 import org.apache.hadoop.hdfs.server.protocol.StorageReceivedDeletedBlocks;
 import org.apache.hadoop.hdfs.util.LightWeightLinkedSet;
+import org.apache.hadoop.metrics2.util.MBeans;
 import org.apache.hadoop.net.Node;
 import org.apache.hadoop.security.UserGroupInformation;
 import org.apache.hadoop.util.Daemon;
@@ -94,6 +97,7 @@ import org.apache.hadoop.util.Time;
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Preconditions;
 import com.google.common.collect.Sets;
+
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -101,7 +105,7 @@ import org.slf4j.LoggerFactory;
  * Keeps information related to the blocks stored in the Hadoop cluster.
  */
 @InterfaceAudience.Private
-public class BlockManager {
+public class BlockManager implements BlockStatsMXBean {
 
   public static final Logger LOG = LoggerFactory.getLogger(BlockManager.class);
   public static final Logger blockLog = NameNode.blockStateChangeLog;
@@ -129,6 +133,7 @@ public class BlockManager {
   private final AtomicLong postponedMisreplicatedBlocksCount = new AtomicLong(0L);
   private final long startupDelayBlockDeletionInMs;
   private final BlockReportLeaseManager blockReportLeaseManager;
+  private ObjectName mxBeanName;
 
   /** Used by metrics */
   public long getPendingReplicationBlocksCount() {
@@ -468,6 +473,7 @@ public class BlockManager {
     pendingReplications.start();
     datanodeManager.activate(conf);
     this.replicationThread.start();
+    mxBeanName = MBeans.register("NameNode", "BlockStats", this);
   }
 
   public void close() {
@@ -3944,6 +3950,8 @@ public class BlockManager {
   public void shutdown() {
     stopReplicationInitializer();
     blocksMap.close();
+    MBeans.unregister(mxBeanName);
+    mxBeanName = null;
   }
   
   public void clear() {
@@ -3954,4 +3962,9 @@ public class BlockManager {
   public BlockReportLeaseManager getBlockReportLeaseManager() {
     return blockReportLeaseManager;
   }
+
+  @Override // BlockStatsMXBean
+  public Map<StorageType, StorageTypeStats> getStorageTypeStats() {
+    return  datanodeManager.getDatanodeStatistics().getStorageTypeStats();
+  }
 }

http://git-wip-us.apache.org/repos/asf/hadoop/blob/d3fed8e6/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockStatsMXBean.java
----------------------------------------------------------------------
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockStatsMXBean.java
b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockStatsMXBean.java
new file mode 100644
index 0000000..f22c537
--- /dev/null
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockStatsMXBean.java
@@ -0,0 +1,36 @@
+/**
+ * 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.blockmanagement;
+
+import java.util.Map;
+
+import org.apache.hadoop.fs.StorageType;
+
+/**
+ * This is an interface used to retrieve statistic information related to
+ * block management.
+ */
+public interface BlockStatsMXBean {
+
+  /**
+   * The statistics of storage types.
+   *
+   * @return get storage statistics per storage type
+   */
+  Map<StorageType, StorageTypeStats> getStorageTypeStats();
+}

http://git-wip-us.apache.org/repos/asf/hadoop/blob/d3fed8e6/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/DatanodeStatistics.java
----------------------------------------------------------------------
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/DatanodeStatistics.java
b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/DatanodeStatistics.java
index c9bc3e5..33eca2e 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/DatanodeStatistics.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/DatanodeStatistics.java
@@ -17,6 +17,9 @@
  */
 package org.apache.hadoop.hdfs.server.blockmanagement;
 
+import java.util.Map;
+
+import org.apache.hadoop.fs.StorageType;
 import org.apache.hadoop.hdfs.protocol.ClientProtocol;
 
 /** Datanode statistics */
@@ -71,4 +74,7 @@ public interface DatanodeStatistics {
 
   /** @return the expired heartbeats */
   public int getExpiredHeartbeats();
+
+  /** @return Storage Tier statistics*/
+  Map<StorageType, StorageTypeStats> getStorageTypeStats();
 }
\ No newline at end of file

http://git-wip-us.apache.org/repos/asf/hadoop/blob/d3fed8e6/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/HeartbeatManager.java
----------------------------------------------------------------------
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/HeartbeatManager.java
b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/HeartbeatManager.java
index 9017fe1..cc9365d 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/HeartbeatManager.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/HeartbeatManager.java
@@ -18,9 +18,15 @@
 package org.apache.hadoop.hdfs.server.blockmanagement;
 
 import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.IdentityHashMap;
 import java.util.List;
+import java.util.Map;
+import java.util.Set;
 
 import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.StorageType;
 import org.apache.hadoop.hdfs.DFSConfigKeys;
 import org.apache.hadoop.hdfs.DFSUtilClient;
 import org.apache.hadoop.hdfs.protocol.DatanodeID;
@@ -189,6 +195,11 @@ class HeartbeatManager implements DatanodeStatistics {
     return stats.expiredHeartbeats;
   }
 
+  @Override
+  public  Map<StorageType, StorageTypeStats> getStorageTypeStats() {
+    return stats.statsMap.get();
+  }
+
   synchronized void register(final DatanodeDescriptor d) {
     if (!d.isAlive) {
       addDatanode(d);
@@ -393,6 +404,9 @@ class HeartbeatManager implements DatanodeStatistics {
    * For decommissioning/decommissioned nodes, only used capacity is counted.
    */
   private static class Stats {
+
+    private final StorageTypeStatsMap statsMap = new StorageTypeStatsMap();
+
     private long capacityTotal = 0L;
     private long capacityUsed = 0L;
     private long capacityRemaining = 0L;
@@ -420,6 +434,14 @@ class HeartbeatManager implements DatanodeStatistics {
       }
       cacheCapacity += node.getCacheCapacity();
       cacheUsed += node.getCacheUsed();
+      Set<StorageType> storageTypes = new HashSet<>();
+      for (DatanodeStorageInfo storageInfo : node.getStorageInfos()) {
+        statsMap.addStorage(storageInfo, node);
+        storageTypes.add(storageInfo.getStorageType());
+      }
+      for (StorageType storageType : storageTypes) {
+        statsMap.addNode(storageType, node);
+      }
     }
 
     private void subtract(final DatanodeDescriptor node) {
@@ -436,6 +458,14 @@ class HeartbeatManager implements DatanodeStatistics {
       }
       cacheCapacity -= node.getCacheCapacity();
       cacheUsed -= node.getCacheUsed();
+      Set<StorageType> storageTypes = new HashSet<>();
+      for (DatanodeStorageInfo storageInfo : node.getStorageInfos()) {
+        statsMap.subtractStorage(storageInfo, node);
+        storageTypes.add(storageInfo.getStorageType());
+      }
+      for (StorageType storageType : storageTypes) {
+        statsMap.subtractNode(storageType, node);
+      }
     }
     
     /** Increment expired heartbeat counter. */
@@ -443,5 +473,69 @@ class HeartbeatManager implements DatanodeStatistics {
       expiredHeartbeats++;
     }
   }
-}
 
+  /** StorageType specific statistics.
+   * For decommissioning/decommissioned nodes, only used capacity is counted.
+   */
+
+  static final class StorageTypeStatsMap {
+
+    private Map<StorageType, StorageTypeStats> storageTypeStatsMap =
+          new IdentityHashMap<>();
+
+    private StorageTypeStatsMap() {}
+
+    private StorageTypeStatsMap(StorageTypeStatsMap other) {
+      storageTypeStatsMap =
+          new IdentityHashMap<>(other.storageTypeStatsMap);
+      for (Map.Entry<StorageType, StorageTypeStats> entry :
+          storageTypeStatsMap.entrySet()) {
+        entry.setValue(new StorageTypeStats(entry.getValue()));
+      }
+    }
+
+    private Map<StorageType, StorageTypeStats> get() {
+      return Collections.unmodifiableMap(storageTypeStatsMap);
+    }
+
+    private void addNode(StorageType storageType,
+        final DatanodeDescriptor node) {
+      StorageTypeStats storageTypeStats =
+          storageTypeStatsMap.get(storageType);
+      if (storageTypeStats == null) {
+        storageTypeStats = new StorageTypeStats();
+        storageTypeStatsMap.put(storageType, storageTypeStats);
+      }
+      storageTypeStats.addNode(node);
+    }
+
+    private void addStorage(final DatanodeStorageInfo info,
+        final DatanodeDescriptor node) {
+      StorageTypeStats storageTypeStats =
+          storageTypeStatsMap.get(info.getStorageType());
+      if (storageTypeStats == null) {
+        storageTypeStats = new StorageTypeStats();
+        storageTypeStatsMap.put(info.getStorageType(), storageTypeStats);
+      }
+      storageTypeStats.addStorage(info, node);
+    }
+
+    private void subtractStorage(final DatanodeStorageInfo info,
+        final DatanodeDescriptor node) {
+      StorageTypeStats storageTypeStats =
+          storageTypeStatsMap.get(info.getStorageType());
+      if (storageTypeStats != null) {
+        storageTypeStats.subtractStorage(info, node);
+      }
+    }
+
+    private void subtractNode(StorageType storageType,
+        final DatanodeDescriptor node) {
+      StorageTypeStats storageTypeStats =
+          storageTypeStatsMap.get(storageType);
+      if (storageTypeStats != null) {
+        storageTypeStats.subtractNode(node);
+      }
+    }
+  }
+}
\ No newline at end of file

http://git-wip-us.apache.org/repos/asf/hadoop/blob/d3fed8e6/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/StorageTypeStats.java
----------------------------------------------------------------------
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/StorageTypeStats.java
b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/StorageTypeStats.java
new file mode 100644
index 0000000..45dcc8d
--- /dev/null
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/StorageTypeStats.java
@@ -0,0 +1,115 @@
+/**
+ * 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.blockmanagement;
+
+import java.beans.ConstructorProperties;
+
+import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.classification.InterfaceStability;
+
+/**
+ * Statistics per StorageType.
+ *
+ */
+@InterfaceAudience.Private
+@InterfaceStability.Evolving
+public class StorageTypeStats {
+  private long capacityTotal = 0L;
+  private long capacityUsed = 0L;
+  private long capacityRemaining = 0L;
+  private long blockPoolUsed = 0L;
+  private int nodesInService = 0;
+
+  @ConstructorProperties({"capacityTotal",
+      "capacityUsed", "capacityRemaining",  "blockPoolUsed", "nodesInService"})
+  public StorageTypeStats(long capacityTotal, long capacityUsed,
+      long capacityRemaining, long blockPoolUsed, int nodesInService) {
+    this.capacityTotal = capacityTotal;
+    this.capacityUsed = capacityUsed;
+    this.capacityRemaining = capacityRemaining;
+    this.blockPoolUsed = blockPoolUsed;
+    this.nodesInService = nodesInService;
+  }
+
+  public long getCapacityTotal() {
+    return capacityTotal;
+  }
+
+  public long getCapacityUsed() {
+    return capacityUsed;
+  }
+
+  public long getCapacityRemaining() {
+    return capacityRemaining;
+  }
+
+  public long getBlockPoolUsed() {
+    return blockPoolUsed;
+  }
+
+  public int getNodesInService() {
+    return nodesInService;
+  }
+
+  StorageTypeStats() {}
+
+  StorageTypeStats(StorageTypeStats other) {
+    capacityTotal = other.capacityTotal;
+    capacityUsed = other.capacityUsed;
+    capacityRemaining = other.capacityRemaining;
+    blockPoolUsed = other.blockPoolUsed;
+    nodesInService = other.nodesInService;
+  }
+
+  void addStorage(final DatanodeStorageInfo info,
+      final DatanodeDescriptor node) {
+    capacityUsed += info.getDfsUsed();
+    blockPoolUsed += info.getBlockPoolUsed();
+    if (!(node.isDecommissionInProgress() || node.isDecommissioned())) {
+      capacityTotal += info.getCapacity();
+      capacityRemaining += info.getRemaining();
+    } else {
+      capacityTotal += info.getDfsUsed();
+    }
+  }
+
+  void addNode(final DatanodeDescriptor node) {
+    if (!(node.isDecommissionInProgress() || node.isDecommissioned())) {
+      nodesInService++;
+    }
+  }
+
+  void subtractStorage(final DatanodeStorageInfo info,
+      final DatanodeDescriptor node) {
+    capacityUsed -= info.getDfsUsed();
+    blockPoolUsed -= info.getBlockPoolUsed();
+    if (!(node.isDecommissionInProgress() || node.isDecommissioned())) {
+      capacityTotal -= info.getCapacity();
+      capacityRemaining -= info.getRemaining();
+    } else {
+      capacityTotal -= info.getDfsUsed();
+    }
+  }
+
+  void subtractNode(final DatanodeDescriptor node) {
+    if (!(node.isDecommissionInProgress() || node.isDecommissioned())) {
+      nodesInService--;
+    }
+  }
+}

http://git-wip-us.apache.org/repos/asf/hadoop/blob/d3fed8e6/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/blockmanagement/TestBlockStatsMXBean.java
----------------------------------------------------------------------
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/blockmanagement/TestBlockStatsMXBean.java
b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/blockmanagement/TestBlockStatsMXBean.java
new file mode 100644
index 0000000..43d983d
--- /dev/null
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/blockmanagement/TestBlockStatsMXBean.java
@@ -0,0 +1,146 @@
+/**
+ * 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.blockmanagement;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.URL;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+
+import org.apache.hadoop.fs.StorageType;
+import org.apache.hadoop.hdfs.HdfsConfiguration;
+import org.apache.hadoop.hdfs.MiniDFSCluster;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.mortbay.util.ajax.JSON;
+
+/**
+ * Class for testing {@link BlockStatsMXBean} implementation
+ */
+public class TestBlockStatsMXBean {
+
+  private MiniDFSCluster cluster;
+
+  @Before
+  public void setup() throws IOException {
+    HdfsConfiguration conf = new HdfsConfiguration();
+    cluster = null;
+    StorageType[][] types = new StorageType[6][];
+    for (int i=0; i<3; i++) {
+      types[i] = new StorageType[] {StorageType.RAM_DISK, StorageType.DISK};
+    }
+    for (int i=3; i< 5; i++) {
+      types[i] = new StorageType[] {StorageType.RAM_DISK, StorageType.ARCHIVE};
+    }
+    types[5] = new StorageType[] {StorageType.RAM_DISK, StorageType.ARCHIVE,
+        StorageType.ARCHIVE};
+
+    cluster = new MiniDFSCluster.Builder(conf).numDataNodes(6).
+        storageTypes(types).storagesPerDatanode(3).build();
+    cluster.waitActive();
+  }
+
+  @After
+  public void tearDown() {
+    if (cluster != null) {
+      cluster.shutdown();
+    }
+  }
+
+  @Test
+  public void testStorageTypeStats() throws Exception {
+    Map<StorageType, StorageTypeStats> storageTypeStatsMap =
+        cluster.getNamesystem().getBlockManager().getStorageTypeStats();
+    assertTrue(storageTypeStatsMap.containsKey(StorageType.RAM_DISK));
+    assertTrue(storageTypeStatsMap.containsKey(StorageType.DISK));
+    assertTrue(storageTypeStatsMap.containsKey(StorageType.ARCHIVE));
+
+    StorageTypeStats storageTypeStats =
+        storageTypeStatsMap.get(StorageType.RAM_DISK);
+    assertEquals(6, storageTypeStats.getNodesInService());
+
+    storageTypeStats = storageTypeStatsMap.get(StorageType.DISK);
+    assertEquals(3, storageTypeStats.getNodesInService());
+
+    storageTypeStats = storageTypeStatsMap.get(StorageType.ARCHIVE);
+    assertEquals(3, storageTypeStats.getNodesInService());
+  }
+
+  protected static String readOutput(URL url) throws IOException {
+    StringBuilder out = new StringBuilder();
+    InputStream in = url.openConnection().getInputStream();
+    byte[] buffer = new byte[64 * 1024];
+    int len = in.read(buffer);
+    while (len > 0) {
+      out.append(new String(buffer, 0, len));
+      len = in.read(buffer);
+    }
+    return out.toString();
+  }
+
+  @Test
+  @SuppressWarnings("unchecked")
+  public void testStorageTypeStatsJMX() throws Exception {
+    URL baseUrl = new URL (cluster.getHttpUri(0));
+    String result = readOutput(new URL(baseUrl, "/jmx"));
+    System.out.println(result);
+
+    Map<String, Object> stat = (Map<String, Object>) JSON.parse(result);
+    Object[] beans =(Object[]) stat.get("beans");
+    Map<String, Object> blockStats  = null;
+    for (Object bean : beans) {
+      Map<String, Object> map = (Map<String, Object>) bean;
+      if (map.get("name").equals("Hadoop:service=NameNode,name=BlockStats")) {
+        blockStats = map;
+      }
+    }
+    assertNotNull(blockStats);
+    Object[] storageTypeStatsList =
+        (Object[])blockStats.get("StorageTypeStats");
+    assertNotNull(storageTypeStatsList);
+    assertEquals (3, storageTypeStatsList.length);
+
+    Set<String> typesPresent = new HashSet<> ();
+    for (Object obj : storageTypeStatsList) {
+      Map<String, Object> entry = (Map<String, Object>)obj;
+      String storageType = (String)entry.get("key");
+      Map<String,Object> storageTypeStats = (Map<String,Object>)entry.get("value");
+      typesPresent.add(storageType);
+      if (storageType.equals("ARCHIVE") || storageType.equals("DISK") ) {
+        assertEquals(3l, storageTypeStats.get("nodesInService"));
+      } else if (storageType.equals("RAM_DISK")) {
+        assertEquals(6l, storageTypeStats.get("nodesInService"));
+      }
+      else {
+        fail();
+      }
+    }
+
+    assertTrue(typesPresent.contains("ARCHIVE"));
+    assertTrue(typesPresent.contains("DISK"));
+    assertTrue(typesPresent.contains("RAM_DISK"));
+  }
+}


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