HDFS-16287. Support to make dfs.namenode.avoid.read.slow.datanode reconfigurable (#3596)

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/DatanodeManager.java

@@ -18,8 +18,6 @@
 package org.apache.hadoop.hdfs.server.blockmanagement;
 
 import static org.apache.hadoop.hdfs.server.protocol.DatanodeProtocol.DNA_ERASURE_CODING_RECONSTRUCTION;
-import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_NAMENODE_BLOCKPLACEMENTPOLICY_EXCLUDE_SLOW_NODES_ENABLED_KEY;
-import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_NAMENODE_BLOCKPLACEMENTPOLICY_EXCLUDE_SLOW_NODES_ENABLED_DEFAULT;
 import static org.apache.hadoop.util.Time.monotonicNow;
 
 import org.apache.commons.lang3.StringUtils;
@@ -141,7 +139,7 @@ public class DatanodeManager {
   private final boolean avoidStaleDataNodesForRead;
 
   /** Whether or not to avoid using slow DataNodes for reading. */
-  private final boolean avoidSlowDataNodesForRead;
+  private volatile boolean avoidSlowDataNodesForRead;
 
   /** Whether or not to consider lad for reading. */
   private final boolean readConsiderLoad;
@@ -217,7 +215,6 @@ public class DatanodeManager {
   private Daemon slowPeerCollectorDaemon;
   private final long slowPeerCollectionInterval;
   private final int maxSlowPeerReportNodes;
-  private boolean excludeSlowNodesEnabled;
 
   @Nullable
   private final SlowDiskTracker slowDiskTracker;
@@ -260,9 +257,6 @@ public class DatanodeManager {
     final Timer timer = new Timer();
     this.slowPeerTracker = dataNodePeerStatsEnabled ?
         new SlowPeerTracker(conf, timer) : null;
-    this.excludeSlowNodesEnabled = conf.getBoolean(
-        DFS_NAMENODE_BLOCKPLACEMENTPOLICY_EXCLUDE_SLOW_NODES_ENABLED_KEY,
-        DFS_NAMENODE_BLOCKPLACEMENTPOLICY_EXCLUDE_SLOW_NODES_ENABLED_DEFAULT);
     this.maxSlowPeerReportNodes = conf.getInt(
         DFSConfigKeys.DFS_NAMENODE_MAX_SLOWPEER_COLLECT_NODES_KEY,
         DFSConfigKeys.DFS_NAMENODE_MAX_SLOWPEER_COLLECT_NODES_DEFAULT);
@@ -270,7 +264,7 @@ public class DatanodeManager {
         DFSConfigKeys.DFS_NAMENODE_SLOWPEER_COLLECT_INTERVAL_KEY,
         DFSConfigKeys.DFS_NAMENODE_SLOWPEER_COLLECT_INTERVAL_DEFAULT,
         TimeUnit.MILLISECONDS);
-    if (slowPeerTracker != null && excludeSlowNodesEnabled) {
+    if (slowPeerTracker != null) {
       startSlowPeerCollector();
     }
     this.slowDiskTracker = dataNodeDiskStatsEnabled ?
@@ -511,7 +505,16 @@ public class DatanodeManager {
   private boolean isSlowNode(String dnUuid) {
     return avoidSlowDataNodesForRead && slowNodesUuidSet.contains(dnUuid);
   }
-  
+
+  public void setAvoidSlowDataNodesForReadEnabled(boolean enable) {
+    this.avoidSlowDataNodesForRead = enable;
+  }
+
+  @VisibleForTesting
+  public boolean getEnableAvoidSlowDataNodesForRead() {
+    return this.avoidSlowDataNodesForRead;
+  }
+
   /**
    * Sort the non-striped located blocks by the distance to the target host.
    *

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

@@ -187,6 +187,8 @@ import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_NAMENODE_GC_TIME_MONITOR_
 import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_NAMENODE_GC_TIME_MONITOR_ENABLE_DEFAULT;
 import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_BLOCK_REPLICATOR_CLASSNAME_KEY;
 import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_BLOCK_PLACEMENT_EC_CLASSNAME_KEY;
+import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_NAMENODE_AVOID_SLOW_DATANODE_FOR_READ_KEY;
+import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_NAMENODE_AVOID_SLOW_DATANODE_FOR_READ_DEFAULT;
 
 import static org.apache.hadoop.util.ExitUtil.terminate;
 import static org.apache.hadoop.util.ToolRunner.confirmPrompt;
@@ -328,7 +330,8 @@ public class NameNode extends ReconfigurableBase implements
           DFS_NAMENODE_REPLICATION_WORK_MULTIPLIER_PER_ITERATION,
           DFS_BLOCK_REPLICATOR_CLASSNAME_KEY,
           DFS_BLOCK_PLACEMENT_EC_CLASSNAME_KEY,
-          DFS_IMAGE_PARALLEL_LOAD_KEY));
+          DFS_IMAGE_PARALLEL_LOAD_KEY,
+          DFS_NAMENODE_AVOID_SLOW_DATANODE_FOR_READ_KEY));
 
   private static final String USAGE = "Usage: hdfs namenode ["
       + StartupOption.BACKUP.getName() + "] | \n\t["
@@ -2197,6 +2200,8 @@ public class NameNode extends ReconfigurableBase implements
       return newVal;
     } else if (property.equals(DFS_IMAGE_PARALLEL_LOAD_KEY)) {
       return reconfigureParallelLoad(newVal);
+    } else if (property.equals(DFS_NAMENODE_AVOID_SLOW_DATANODE_FOR_READ_KEY)) {
+      return reconfigureSlowNodesParameters(datanodeManager, property, newVal);
     } else {
       throw new ReconfigurationException(property, newVal, getConf().get(
           property));
@@ -2383,6 +2388,27 @@ public class NameNode extends ReconfigurableBase implements
     return Boolean.toString(enableParallelLoad);
   }
 
+  String reconfigureSlowNodesParameters(final DatanodeManager datanodeManager,
+      final String property, final String newVal) throws ReconfigurationException {
+    namesystem.writeLock();
+    boolean enable;
+    try {
+      if (newVal == null) {
+        enable = DFS_NAMENODE_AVOID_SLOW_DATANODE_FOR_READ_DEFAULT;
+      } else {
+        enable = Boolean.parseBoolean(newVal);
+      }
+      datanodeManager.setAvoidSlowDataNodesForReadEnabled(enable);
+      LOG.info("RECONFIGURE* changed {} to {}", property, newVal);
+      return Boolean.toString(enable);
+    } catch (IllegalArgumentException e) {
+      throw new ReconfigurationException(property, newVal, getConf().get(
+          property), e);
+    } finally {
+      namesystem.writeUnlock();
+    }
+  }
+
   @Override  // ReconfigurableBase
   protected Configuration getNewConf() {
     return new HdfsConfiguration();

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

@@ -51,6 +51,7 @@ import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_NAMENODE_HEARTBEAT_RECHEC
 import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_STORAGE_POLICY_SATISFIER_MODE_KEY;
 import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_STORAGE_POLICY_SATISFIER_MODE_DEFAULT;
 import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_BLOCK_INVALIDATE_LIMIT_KEY;
+import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_NAMENODE_AVOID_SLOW_DATANODE_FOR_READ_KEY;
 import static org.apache.hadoop.fs.CommonConfigurationKeys.IPC_BACKOFF_ENABLE_DEFAULT;
 
 public class TestNameNodeReconfigure {
@@ -394,6 +395,23 @@ public class TestNameNodeReconfigure {
     assertEquals(true, FSImageFormatProtobuf.getEnableParallelLoad());
   }
 
+  @Test
+  public void testEnableSlowNodesParametersAfterReconfigured()
+      throws ReconfigurationException {
+    final NameNode nameNode = cluster.getNameNode();
+    final DatanodeManager datanodeManager = nameNode.namesystem
+        .getBlockManager().getDatanodeManager();
+
+    // By default, avoidSlowDataNodesForRead is false.
+    assertEquals(false, datanodeManager.getEnableAvoidSlowDataNodesForRead());
+
+    nameNode.reconfigureProperty(
+        DFS_NAMENODE_AVOID_SLOW_DATANODE_FOR_READ_KEY, Boolean.toString(true));
+
+    // After reconfigured, avoidSlowDataNodesForRead is true.
+    assertEquals(true, datanodeManager.getEnableAvoidSlowDataNodesForRead());
+  }
+
   @After
   public void shutDown() throws IOException {
     if (cluster != null) {

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/tools/TestDFSAdmin.java

@@ -38,6 +38,7 @@ import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_IMAGE_PARALLEL_LOAD_KEY;
 import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_NAMENODE_HEARTBEAT_RECHECK_INTERVAL_KEY;
 import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_BLOCK_PLACEMENT_EC_CLASSNAME_KEY;
 import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_BLOCK_REPLICATOR_CLASSNAME_KEY;
+import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_NAMENODE_AVOID_SLOW_DATANODE_FOR_READ_KEY;
 
 import org.apache.commons.io.FileUtils;
 import org.apache.commons.text.TextStringBuilder;
@@ -430,12 +431,13 @@ public class TestDFSAdmin {
     final List<String> outs = Lists.newArrayList();
     final List<String> errs = Lists.newArrayList();
     getReconfigurableProperties("namenode", address, outs, errs);
-    assertEquals(13, outs.size());
+    assertEquals(14, outs.size());
     assertEquals(DFS_BLOCK_PLACEMENT_EC_CLASSNAME_KEY, outs.get(1));
     assertEquals(DFS_BLOCK_REPLICATOR_CLASSNAME_KEY, outs.get(2));
     assertEquals(DFS_HEARTBEAT_INTERVAL_KEY, outs.get(3));
     assertEquals(DFS_IMAGE_PARALLEL_LOAD_KEY, outs.get(4));
-    assertEquals(DFS_NAMENODE_HEARTBEAT_RECHECK_INTERVAL_KEY, outs.get(5));
+    assertEquals(DFS_NAMENODE_AVOID_SLOW_DATANODE_FOR_READ_KEY, outs.get(5));
+    assertEquals(DFS_NAMENODE_HEARTBEAT_RECHECK_INTERVAL_KEY, outs.get(6));
     assertEquals(errs.size(), 0);
   }