HDFS-8143. Mover should exit after some retry when failed to move blocks. Contributed by surendra singh lilhore

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

@@ -351,6 +351,8 @@ public class DFSConfigKeys extends CommonConfigurationKeys {
   public static final long    DFS_MOVER_MOVEDWINWIDTH_DEFAULT = 5400*1000L;
   public static final String  DFS_MOVER_MOVERTHREADS_KEY = "dfs.mover.moverThreads";
   public static final int     DFS_MOVER_MOVERTHREADS_DEFAULT = 1000;
+  public static final String  DFS_MOVER_RETRY_MAX_ATTEMPTS_KEY = "dfs.mover.retry.max.attempts";
+  public static final int     DFS_MOVER_RETRY_MAX_ATTEMPTS_DEFAULT = 10;
 
   public static final String  DFS_DATANODE_ADDRESS_KEY = "dfs.datanode.address";
   public static final int     DFS_DATANODE_DEFAULT_PORT = 50010;

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/mover/Mover.java

@@ -58,6 +58,7 @@ import java.io.InputStreamReader;
 import java.net.URI;
 import java.text.DateFormat;
 import java.util.*;
+import java.util.concurrent.atomic.AtomicInteger;
 
 @InterfaceAudience.Private
 public class Mover {
@@ -107,10 +108,12 @@ public class Mover {
   private final Dispatcher dispatcher;
   private final StorageMap storages;
   private final List<Path> targetPaths;
+  private final int retryMaxAttempts;
+  private final AtomicInteger retryCount;
 
   private final BlockStoragePolicy[] blockStoragePolicies;
 
-  Mover(NameNodeConnector nnc, Configuration conf) {
+  Mover(NameNodeConnector nnc, Configuration conf, AtomicInteger retryCount) {
     final long movedWinWidth = conf.getLong(
         DFSConfigKeys.DFS_MOVER_MOVEDWINWIDTH_KEY,
         DFSConfigKeys.DFS_MOVER_MOVEDWINWIDTH_DEFAULT);
@@ -120,7 +123,10 @@ public class Mover {
     final int maxConcurrentMovesPerNode = conf.getInt(
         DFSConfigKeys.DFS_DATANODE_BALANCE_MAX_NUM_CONCURRENT_MOVES_KEY,
         DFSConfigKeys.DFS_DATANODE_BALANCE_MAX_NUM_CONCURRENT_MOVES_DEFAULT);
-
+    this.retryMaxAttempts = conf.getInt(
+        DFSConfigKeys.DFS_MOVER_RETRY_MAX_ATTEMPTS_KEY,
+        DFSConfigKeys.DFS_MOVER_RETRY_MAX_ATTEMPTS_DEFAULT);
+    this.retryCount = retryCount;
     this.dispatcher = new Dispatcher(nnc, Collections.<String> emptySet(),
         Collections.<String> emptySet(), movedWinWidth, moverThreads, 0,
         maxConcurrentMovesPerNode, conf);
@@ -255,14 +261,27 @@ public class Mover {
      * @return whether there is still remaining migration work for the next
      *         round
      */
-    private boolean processNamespace() {
+    private boolean processNamespace() throws IOException {
       getSnapshottableDirs();
       boolean hasRemaining = false;
       for (Path target : targetPaths) {
         hasRemaining |= processPath(target.toUri().getPath());
       }
       // wait for pending move to finish and retry the failed migration
-      hasRemaining |= Dispatcher.waitForMoveCompletion(storages.targets.values());
+      boolean hasFailed = Dispatcher.waitForMoveCompletion(storages.targets
+          .values());
+      if (hasFailed) {
+        if (retryCount.get() == retryMaxAttempts) {
+          throw new IOException("Failed to move some block's after "
+              + retryMaxAttempts + " retries.");
+        } else {
+          retryCount.incrementAndGet();
+        }
+      } else {
+        // Reset retry count if no failure.
+        retryCount.set(0);
+      }
+      hasRemaining |= hasFailed;
       return hasRemaining;
     }
 
@@ -528,6 +547,7 @@ public class Mover {
             DFSConfigKeys.DFS_HEARTBEAT_INTERVAL_DEFAULT) * 2000 +
         conf.getLong(DFSConfigKeys.DFS_NAMENODE_REPLICATION_INTERVAL_KEY,
             DFSConfigKeys.DFS_NAMENODE_REPLICATION_INTERVAL_DEFAULT) * 1000;
+    AtomicInteger retryCount = new AtomicInteger(0);
     LOG.info("namenodes = " + namenodes);
     
     List<NameNodeConnector> connectors = Collections.emptyList();
@@ -541,7 +561,7 @@ public class Mover {
         Iterator<NameNodeConnector> iter = connectors.iterator();
         while (iter.hasNext()) {
           NameNodeConnector nnc = iter.next();
-          final Mover m = new Mover(nnc, conf);
+          final Mover m = new Mover(nnc, conf, retryCount);
           final ExitStatus r = m.run();
 
           if (r == ExitStatus.SUCCESS) {

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/mover/TestMover.java

@@ -20,12 +20,14 @@ package org.apache.hadoop.hdfs.server.mover;
 import java.io.IOException;
 import java.net.URI;
 import java.util.*;
+import java.util.concurrent.atomic.AtomicInteger;
 
 import com.google.common.collect.Maps;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.FSDataOutputStream;
 import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.fs.StorageType;
+import org.apache.hadoop.hdfs.DFSConfigKeys;
 import org.apache.hadoop.hdfs.DistributedFileSystem;
 import org.apache.hadoop.hdfs.DFSTestUtil;
 import org.apache.hadoop.hdfs.DFSUtil;
@@ -34,6 +36,7 @@ import org.apache.hadoop.hdfs.MiniDFSCluster;
 import org.apache.hadoop.hdfs.MiniDFSNNTopology;
 import org.apache.hadoop.hdfs.protocol.LocatedBlock;
 import org.apache.hadoop.hdfs.server.balancer.Dispatcher.DBlock;
+import org.apache.hadoop.hdfs.server.balancer.ExitStatus;
 import org.apache.hadoop.hdfs.server.balancer.NameNodeConnector;
 import org.apache.hadoop.hdfs.server.mover.Mover.MLocation;
 import org.apache.hadoop.hdfs.server.namenode.ha.HATestUtil;
@@ -54,7 +57,7 @@ public class TestMover {
     final List<NameNodeConnector> nncs = NameNodeConnector.newNameNodeConnectors(
         nnMap, Mover.class.getSimpleName(), Mover.MOVER_ID_PATH, conf,
         NameNodeConnector.DEFAULT_MAX_IDLE_ITERATIONS);
-    return new Mover(nncs.get(0), conf);
+    return new Mover(nncs.get(0), conf, new AtomicInteger(0));
   }
 
   @Test
@@ -324,4 +327,38 @@ public class TestMover {
       cluster.shutdown();
     }
   }
+
+  @Test
+  public void testMoverFailedRetry() throws Exception {
+    // HDFS-8147
+    final Configuration conf = new HdfsConfiguration();
+    conf.set(DFSConfigKeys.DFS_MOVER_RETRY_MAX_ATTEMPTS_KEY, "2");
+    final MiniDFSCluster cluster = new MiniDFSCluster.Builder(conf)
+        .numDataNodes(3)
+        .storageTypes(
+            new StorageType[][] {{StorageType.DISK, StorageType.ARCHIVE},
+                {StorageType.DISK, StorageType.ARCHIVE},
+                {StorageType.DISK, StorageType.ARCHIVE}}).build();
+    try {
+      cluster.waitActive();
+      final DistributedFileSystem dfs = cluster.getFileSystem();
+      final String file = "/testMoverFailedRetry";
+      // write to DISK
+      final FSDataOutputStream out = dfs.create(new Path(file), (short) 2);
+      out.writeChars("testMoverFailedRetry");
+      out.close();
+
+      // Delete block file so, block move will fail with FileNotFoundException
+      LocatedBlock lb = dfs.getClient().getLocatedBlocks(file, 0).get(0);
+      cluster.corruptBlockOnDataNodesByDeletingBlockFile(lb.getBlock());
+      // move to ARCHIVE
+      dfs.setStoragePolicy(new Path(file), "COLD");
+      int rc = ToolRunner.run(conf, new Mover.Cli(),
+          new String[] {"-p", file.toString()});
+      Assert.assertEquals("Movement should fail after some retry",
+          ExitStatus.IO_EXCEPTION.getExitCode(), rc);
+    } finally {
+      cluster.shutdown();
+    }
+  }
 }