HDFS-16917 Add transfer rate quantile metrics for DataNode reads (#5397)

Co-authored-by: Ravindra Dingankar <rdingankar@linkedin.com>

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

@@ -368,6 +368,9 @@ Each metrics record contains tags such as SessionId and Hostname as additional i
 |:---- |:---- |
 | `BytesWritten` | Total number of bytes written to DataNode |
 | `BytesRead` | Total number of bytes read from DataNode |
+| `ReadTransferRateNumOps` | Total number of data read transfers |
+| `ReadTransferRateAvgTime` | Average transfer rate of bytes read from DataNode, measured in bytes per second. |
+| `ReadTransferRate`*num*`s(50/75/90/95/99)thPercentileRate` | The 50/75/90/95/99th percentile of the transfer rate of bytes read from DataNode, measured in bytes per second. |
 | `BlocksWritten` | Total number of blocks written to DataNode |
 | `BlocksRead` | Total number of blocks read from DataNode |
 | `BlocksReplicated` | Total number of blocks replicated |

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSUtil.java

@@ -69,6 +69,7 @@
 import org.apache.commons.lang3.StringUtils;
 import org.apache.hadoop.fs.ParentNotDirectoryException;
 import org.apache.hadoop.fs.UnresolvedLinkException;
+import org.apache.hadoop.hdfs.server.datanode.metrics.DataNodeMetrics;
 import org.apache.hadoop.hdfs.server.namenode.FSDirectory;
 import org.apache.hadoop.hdfs.server.namenode.INodesInPath;
 import org.apache.hadoop.ipc.ProtobufRpcEngine;
@@ -1893,4 +1894,18 @@ public static boolean isParentEntry(final String path, final String parent) {
     return path.charAt(parent.length()) == Path.SEPARATOR_CHAR
         || parent.equals(Path.SEPARATOR);
   }
+
+  /**
+   * Add transfer rate metrics for valid data read and duration values.
+   * @param metrics metrics for datanodes
+   * @param read bytes read
+   * @param duration read duration
+   */
+  public static void addTransferRateMetric(final DataNodeMetrics metrics, final long read, final long duration) {
+    if (read >= 0 && duration > 0) {
+        metrics.addReadTransferRate(read * 1000 / duration);
+    } else {
+      LOG.warn("Unexpected value for data transfer bytes={} duration={}", read, duration);
+    }
+  }
 }

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

@@ -24,6 +24,7 @@
 import org.apache.commons.logging.Log;
 import org.apache.hadoop.fs.FsTracer;
 import org.apache.hadoop.fs.StorageType;
+import org.apache.hadoop.hdfs.DFSUtil;
 import org.apache.hadoop.hdfs.DFSUtilClient;
 import org.apache.hadoop.hdfs.ExtendedBlockId;
 import org.apache.hadoop.hdfs.net.Peer;
@@ -633,6 +634,7 @@ public void readBlock(final ExtendedBlock block,
       datanode.metrics.incrBytesRead((int) read);
       datanode.metrics.incrBlocksRead();
       datanode.metrics.incrTotalReadTime(duration);
+      DFSUtil.addTransferRateMetric(datanode.metrics, read, duration);
     } catch ( SocketException ignored ) {
       LOG.trace("{}:Ignoring exception while serving {} to {}",
           dnR, block, remoteAddress, ignored);
@@ -1122,6 +1124,7 @@ public void copyBlock(final ExtendedBlock block,
       datanode.metrics.incrBytesRead((int) read);
       datanode.metrics.incrBlocksRead();
       datanode.metrics.incrTotalReadTime(duration);
+      DFSUtil.addTransferRateMetric(datanode.metrics, read, duration);
       
       LOG.info("Copied {} to {}", block, peer.getRemoteAddressString());
     } catch (IOException ioe) {

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

@@ -61,6 +61,8 @@ public class DataNodeMetrics {
   @Metric MutableCounterLong bytesRead;
   @Metric("Milliseconds spent reading")
   MutableCounterLong totalReadTime;
+  @Metric private MutableRate readTransferRate;
+  final private MutableQuantiles[] readTransferRateQuantiles;
   @Metric MutableCounterLong blocksWritten;
   @Metric MutableCounterLong blocksRead;
   @Metric MutableCounterLong blocksReplicated;
@@ -201,6 +203,7 @@ public DataNodeMetrics(String name, String sessionId, int[] intervals,
     sendDataPacketTransferNanosQuantiles = new MutableQuantiles[len];
     ramDiskBlocksEvictionWindowMsQuantiles = new MutableQuantiles[len];
     ramDiskBlocksLazyPersistWindowMsQuantiles = new MutableQuantiles[len];
+    readTransferRateQuantiles = new MutableQuantiles[len];
 
     for (int i = 0; i < len; i++) {
       int interval = intervals[i];
@@ -229,6 +232,10 @@ public DataNodeMetrics(String name, String sessionId, int[] intervals,
           "ramDiskBlocksLazyPersistWindows" + interval + "s",
           "Time between the RamDisk block write and disk persist in ms",
           "ops", "latency", interval);
+      readTransferRateQuantiles[i] = registry.newQuantiles(
+          "readTransferRate" + interval + "s",
+          "Rate at which bytes are read from datanode calculated in bytes per second",
+          "ops", "rate", interval);
     }
   }
 
@@ -290,6 +297,13 @@ public void addIncrementalBlockReport(long latency,
     }
   }
 
+  public void addReadTransferRate(long readTransferRate) {
+    this.readTransferRate.add(readTransferRate);
+    for (MutableQuantiles q : readTransferRateQuantiles) {
+      q.add(readTransferRate);
+    }
+  }
+
   public void addCacheReport(long latency) {
     cacheReports.add(latency);
   }

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDFSUtil.java

@@ -45,6 +45,7 @@
 import static org.junit.Assert.assertThat;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
+import static org.mockito.Mockito.*;
 
 import java.io.File;
 import java.io.IOException;
@@ -70,6 +71,7 @@
 import org.apache.hadoop.hdfs.protocol.HdfsConstants;
 import org.apache.hadoop.hdfs.protocol.LocatedBlock;
 import org.apache.hadoop.hdfs.protocol.LocatedBlocks;
+import org.apache.hadoop.hdfs.server.datanode.metrics.DataNodeMetrics;
 import org.apache.hadoop.hdfs.server.namenode.NameNode;
 import org.apache.hadoop.hdfs.server.namenode.ha.ConfiguredFailoverProxyProvider;
 import org.apache.hadoop.http.HttpConfig;
@@ -1109,4 +1111,18 @@ public void testErrorMessageForInvalidNameservice() throws Exception {
     LambdaTestUtils.intercept(IOException.class, expectedErrorMessage,
         ()->DFSUtil.getNNServiceRpcAddressesForCluster(conf));
   }
+
+  @Test
+  public void testAddTransferRateMetricForValidValues() {
+    DataNodeMetrics mockMetrics = mock(DataNodeMetrics.class);
+    DFSUtil.addTransferRateMetric(mockMetrics, 100, 10);
+    verify(mockMetrics).addReadTransferRate(10000);
+  }
+
+  @Test
+  public void testAddTransferRateMetricForInvalidValue() {
+    DataNodeMetrics mockMetrics = mock(DataNodeMetrics.class);
+    DFSUtil.addTransferRateMetric(mockMetrics, 100, 0);
+    verify(mockMetrics, times(0)).addReadTransferRate(anyLong());
+  }
 }

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

@@ -274,6 +274,7 @@ public void testTimeoutMetric() throws Exception {
   @Test(timeout=120000)
   public void testDataNodeTimeSpend() throws Exception {
     Configuration conf = new HdfsConfiguration();
+    conf.set(DFSConfigKeys.DFS_METRICS_PERCENTILES_INTERVALS_KEY, "" + 60);
     MiniDFSCluster cluster = new MiniDFSCluster.Builder(conf).build();
     try {
       final FileSystem fs = cluster.getFileSystem();
@@ -285,6 +286,7 @@ public void testDataNodeTimeSpend() throws Exception {
 
       final long startWriteValue = getLongCounter("TotalWriteTime", rb);
       final long startReadValue = getLongCounter("TotalReadTime", rb);
+      assertCounter("ReadTransferRateNumOps", 0L, rb);
       final AtomicInteger x = new AtomicInteger(0);
 
       // Lets Metric system update latest metrics
@@ -304,6 +306,8 @@ public Boolean get() {
           MetricsRecordBuilder rbNew = getMetrics(datanode.getMetrics().name());
           final long endWriteValue = getLongCounter("TotalWriteTime", rbNew);
           final long endReadValue = getLongCounter("TotalReadTime", rbNew);
+          assertCounter("ReadTransferRateNumOps", 1L, rbNew);
+          assertQuantileGauges("ReadTransferRate" + "60s", rbNew, "Rate");
           return endWriteValue > startWriteValue
               && endReadValue > startReadValue;
         }