HDFS-15814. Make some parameters configurable for DataNodeDiskMetrics (#2676)

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

@@ -676,6 +676,14 @@ public class DFSConfigKeys extends CommonConfigurationKeys {
       "dfs.datanode.slowpeer.low.threshold.ms";
   public static final long DFS_DATANODE_SLOWPEER_LOW_THRESHOLD_MS_DEFAULT =
       5L;
+  public static final String DFS_DATANODE_MIN_OUTLIER_DETECTION_DISKS_KEY =
+      "dfs.datanode.min.outlier.detection.disks";
+  public static final long DFS_DATANODE_MIN_OUTLIER_DETECTION_DISKS_DEFAULT =
+      5L;
+  public static final String DFS_DATANODE_SLOWDISK_LOW_THRESHOLD_MS_KEY =
+      "dfs.datanode.slowdisk.low.threshold.ms";
+  public static final long DFS_DATANODE_SLOWDISK_LOW_THRESHOLD_MS_DEFAULT =
+      20L;
   public static final String  DFS_DATANODE_HOST_NAME_KEY =
       HdfsClientConfigKeys.DeprecatedKeys.DFS_DATANODE_HOST_NAME_KEY;
   public static final String  DFS_NAMENODE_CHECKPOINT_DIR_KEY =

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

@@ -1489,7 +1489,7 @@ public class DataNode extends ReconfigurableBase
 
     if (dnConf.diskStatsEnabled) {
       diskMetrics = new DataNodeDiskMetrics(this,
-          dnConf.outliersReportIntervalMs);
+          dnConf.outliersReportIntervalMs, getConf());
     }
   }
 

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

@@ -17,6 +17,8 @@
  */
 package org.apache.hadoop.hdfs.server.datanode.metrics;
 
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.hdfs.DFSConfigKeys;
 import org.apache.hadoop.thirdparty.com.google.common.annotations.VisibleForTesting;
 import org.apache.hadoop.thirdparty.com.google.common.collect.ImmutableMap;
 import org.apache.hadoop.thirdparty.com.google.common.collect.Maps;
@@ -48,8 +50,6 @@ public class DataNodeDiskMetrics {
       DataNodeDiskMetrics.class);
 
   private DataNode dn;
-  private final long MIN_OUTLIER_DETECTION_DISKS = 5;
-  private final long SLOW_DISK_LOW_THRESHOLD_MS = 20;
   private final long detectionInterval;
   private volatile boolean shouldRun;
   private OutlierDetector slowDiskDetector;
@@ -61,11 +61,27 @@ public class DataNodeDiskMetrics {
   // code, status should not be overridden by daemon thread.
   private boolean overrideStatus = true;
 
-  public DataNodeDiskMetrics(DataNode dn, long diskOutlierDetectionIntervalMs) {
+  /**
+   * Minimum number of disks to run outlier detection.
+   */
+  private final long minOutlierDetectionDisks;
+  /**
+   * Threshold in milliseconds below which a disk is definitely not slow.
+   */
+  private final long lowThresholdMs;
+
+  public DataNodeDiskMetrics(DataNode dn, long diskOutlierDetectionIntervalMs,
+      Configuration conf) {
     this.dn = dn;
     this.detectionInterval = diskOutlierDetectionIntervalMs;
-    slowDiskDetector = new OutlierDetector(MIN_OUTLIER_DETECTION_DISKS,
-        SLOW_DISK_LOW_THRESHOLD_MS);
+    minOutlierDetectionDisks =
+        conf.getLong(DFSConfigKeys.DFS_DATANODE_MIN_OUTLIER_DETECTION_DISKS_KEY,
+            DFSConfigKeys.DFS_DATANODE_MIN_OUTLIER_DETECTION_DISKS_DEFAULT);
+    lowThresholdMs =
+        conf.getLong(DFSConfigKeys.DFS_DATANODE_SLOWDISK_LOW_THRESHOLD_MS_KEY,
+            DFSConfigKeys.DFS_DATANODE_SLOWDISK_LOW_THRESHOLD_MS_DEFAULT);
+    slowDiskDetector =
+        new OutlierDetector(minOutlierDetectionDisks, lowThresholdMs);
     shouldRun = true;
     startDiskOutlierDetectionThread();
   }

hadoop-hdfs-project/hadoop-hdfs/src/main/resources/hdfs-default.xml

@@ -2370,6 +2370,22 @@
   </description>
 </property>
 
+<property>
+  <name>dfs.datanode.min.outlier.detection.disks</name>
+  <value>5</value>
+  <description>
+    Minimum number of disks to run outlier detection.
+  </description>
+</property>
+
+<property>
+  <name>dfs.datanode.slowdisk.low.threshold.ms</name>
+  <value>20</value>
+  <description>
+    Threshold in milliseconds below which a disk is definitely not slow.
+  </description>
+</property>
+
 <property>
   <name>hadoop.user.group.metrics.percentiles.intervals</name>
   <value></value>