HDFS-8911. NameNode Metric : Add Editlog counters as a JMX metric. (Contributed by Anu Engineer)

hadoop-common-project/hadoop-common/src/site/markdown/Metrics.md

@@ -237,6 +237,8 @@ Each metrics record contains tags such as HAState and Hostname as additional inf
 | `HAState` | (HA-only) Current state of the NameNode: initializing or active or standby or stopping state |
 | `FSState` | Current state of the file system: Safemode or Operational |
 | `LockQueueLength` | Number of threads waiting to acquire FSNameSystem lock |
+| `TotalSyncCount` | Total number of sync operations performed by edit log |
+| `TotalSyncTimes` | Total number of milliseconds spent by various edit logs in sync operation|
 
 JournalNode
 -----------

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

@@ -811,6 +811,9 @@ Release 2.8.0 - UNRELEASED
     HDFS-8826. In Balancer, add an option to specify the source node list
     so that balancer only selects blocks to move from those nodes.  (szetszwo)
 
+    HDFS-8911. NameNode Metric : Add Editlog counters as a JMX metric.
+    (Anu Engineer via Arpit Agarwal)
+
   OPTIMIZATIONS
 
     HDFS-8026. Trace FSOutputSummer#writeChecksumChunks rather than

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSEditLog.java

@@ -1691,4 +1691,11 @@ public class FSEditLog implements LogsPurgeable {
     }
   }
 
+  /**
+   +   * Return total number of syncs happened on this edit log.
+   +   * @return long - count
+   +   */
+  public long getTotalSyncCount() {
+    return editLogStream.getNumSync();
+  }
 }

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSNamesystem.java

@@ -7277,5 +7277,24 @@ public class FSNamesystem implements Namesystem, FSNamesystemMBean,
     }
   }
 
+  /**
+   * Return total number of Sync Operations on FSEditLog.
+   */
+  @Override
+  @Metric({"TotalSyncCount",
+              "Total number of sync operations performed on edit logs"})
+  public long getTotalSyncCount() {
+    return fsImage.editLog.getTotalSyncCount();
+  }
+
+  /**
+   * Return total time spent doing sync operations on FSEditLog.
+   */
+  @Override
+  @Metric({"TotalSyncTimes",
+              "Total time spend in sync operation on various edit logs"})
+  public String getTotalSyncTimes() {
+    return fsImage.editLog.getJournalSet().getSyncTimes();
+  }
 }
 

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/metrics/FSNamesystemMBean.java

@@ -198,4 +198,14 @@ public interface FSNamesystemMBean {
    * @return int - Number of Threads waiting to acquire FSNameSystemLock
    */
   int getFsLockQueueLength();
+
+  /**
+   * Return total number of Sync Operations on FSEditLog.
+   */
+  long getTotalSyncCount();
+
+  /**
+   * Return total time spent doing sync operations on FSEditLog.
+   */
+  String getTotalSyncTimes();
 }

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

@@ -30,6 +30,8 @@ import javax.management.MBeanInfo;
 import javax.management.MBeanServer;
 import javax.management.ObjectName;
 
+import org.apache.hadoop.fs.FileSystem;
+import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.hdfs.MiniDFSCluster;
 import org.junit.Test;
@@ -159,4 +161,34 @@ public class TestFSNamesystemMBean {
       }
     }
   }
+
+  @Test(timeout = 120000)
+  public void testFsEditLogMetrics() throws Exception {
+    final Configuration conf = new Configuration();
+    MiniDFSCluster cluster = null;
+    try {
+      cluster = new MiniDFSCluster.Builder(conf).numDataNodes(0).build();
+      cluster.waitActive();
+      MBeanServer mbs = ManagementFactory.getPlatformMBeanServer();
+      ObjectName mxbeanNameFs =
+          new ObjectName("Hadoop:service=NameNode,name=FSNamesystemState");
+
+      FileSystem fs = cluster.getFileSystem();
+      final int NUM_OPS = 10;
+      for (int i = 0; i < NUM_OPS; i++) {
+        final Path path = new Path(String.format("/user%d", i));
+        fs.mkdirs(path);
+      }
+
+      long syncCount = (long) mbs.getAttribute(mxbeanNameFs, "TotalSyncCount");
+      String syncTimes =
+          (String) mbs.getAttribute(mxbeanNameFs, "TotalSyncTimes");
+      assertTrue(syncCount > 0);
+      assertNotNull(syncTimes);
+    } finally {
+      if (cluster != null) {
+        cluster.shutdown();
+      }
+    }
+  }
 }