HDFS-2868. Expose xceiver counts via the DataNode MXBean. (harsh)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1240897 13f79535-47bb-0310-9956-ffa450edef68

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

@@ -298,6 +298,8 @@ Release 0.23.1 - UNRELEASED
 
     HDFS-2857. Cleanup BlockInfo class. (suresh)
 
+    HDFS-2868. Expose xceiver counts via the DataNode MXBean. (harsh)
+
   OPTIMIZATIONS
 
     HDFS-2130. Switch default checksum to CRC32C. (todd)

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

@@ -1295,7 +1295,8 @@ public class DataNode extends Configured
   }
     
   /** Number of concurrent xceivers per node. */
-  int getXceiverCount() {
+  @Override // DataNodeMXBean
+  public int getXceiverCount() {
     return threadGroup == null ? 0 : threadGroup.activeCount();
   }
     

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

@@ -70,5 +70,10 @@ public interface DataNodeMXBean {
    * @return the cluster id
    */
   public String getClusterId();
-  
+
+  /**
+   * Returns an estimate of the number of Datanode threads
+   * actively transferring blocks.
+   */
+  public int getXceiverCount();
 }

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

@@ -65,6 +65,11 @@ public class TestDataNodeMXBean {
       String volumeInfo = (String)mbs.getAttribute(mxbeanName, "VolumeInfo");
       Assert.assertEquals(replaceDigits(datanode.getVolumeInfo()),
           replaceDigits(volumeInfo));
+      // Ensure mxbean's XceiverCount is same as the DataNode's
+      // live value.
+      int xceiverCount = (Integer)mbs.getAttribute(mxbeanName,
+          "XceiverCount");
+      Assert.assertEquals(datanode.getXceiverCount(), xceiverCount);
     } finally {
       if (cluster != null) {cluster.shutdown();}
     }