HDFS-12349. Improve log message when it could not alloc enough blocks for EC. (lei)

hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/DFSStripedOutputStream.java

@@ -260,6 +260,7 @@ public class DFSStripedOutputStream extends DFSOutputStream
 
   private final Coordinator coordinator;
   private final CellBuffers cellBuffers;
+  private final ErasureCodingPolicy ecPolicy;
   private final RawErasureEncoder encoder;
   private final List<StripedDataStreamer> streamers;
   private final DFSPacket[] currentPackets; // current Packet of each streamer
@@ -286,7 +287,7 @@ public class DFSStripedOutputStream extends DFSOutputStream
       LOG.debug("Creating DFSStripedOutputStream for " + src);
     }
 
-    final ErasureCodingPolicy ecPolicy = stat.getErasureCodingPolicy();
+    ecPolicy = stat.getErasureCodingPolicy();
     final int numParityBlocks = ecPolicy.getNumParityUnits();
     cellSize = ecPolicy.getCellSize();
     numDataBlocks = ecPolicy.getNumDataUnits();
@@ -478,11 +479,6 @@ public class DFSStripedOutputStream extends DFSOutputStream
     final LocatedBlock lb = addBlock(excludedNodes, dfsClient, src,
         currentBlockGroup, fileId, favoredNodes, getAddBlockFlags());
     assert lb.isStriped();
-    if (lb.getLocations().length < numDataBlocks) {
-      throw new IOException("Failed to get " + numDataBlocks
-          + " nodes from namenode: blockGroupSize= " + numAllBlocks
-          + ", blocks.length= " + lb.getLocations().length);
-    }
     // assign the new block to the current block group
     currentBlockGroup = lb.getBlock();
     blockGroupIndex++;
@@ -494,11 +490,16 @@ public class DFSStripedOutputStream extends DFSOutputStream
       StripedDataStreamer si = getStripedDataStreamer(i);
       assert si.isHealthy();
       if (blocks[i] == null) {
+        // allocBlock() should guarantee that all data blocks are successfully
+        // allocated.
+        assert i >= numDataBlocks;
         // Set exception and close streamer as there is no block locations
         // found for the parity block.
-        LOG.warn("Failed to get block location for parity block, index=" + i);
+        LOG.warn("Cannot allocate parity block(index={}, policy={}). " +
+            "Not enough datanodes? Excluded nodes={}", i,  ecPolicy.getName(),
+            excludedNodes);
         si.getLastException().set(
-            new IOException("Failed to get following block, i=" + i));
+            new IOException("Failed to get parity block, index=" + i));
         si.getErrorState().setInternalError();
         si.close(true);
       } else {

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

@@ -2057,6 +2057,7 @@ public class BlockManager implements BlockStatsMXBean {
       final List<String> favoredNodes,
       final byte storagePolicyID,
       final BlockType blockType,
+      final ErasureCodingPolicy ecPolicy,
       final EnumSet<AddBlockFlag> flags) throws IOException {
     List<DatanodeDescriptor> favoredDatanodeDescriptors = 
         getDatanodeDescriptors(favoredNodes);
@@ -2067,14 +2068,23 @@ public class BlockManager implements BlockStatsMXBean {
     final DatanodeStorageInfo[] targets = blockplacement.chooseTarget(src,
         numOfReplicas, client, excludedNodes, blocksize, 
         favoredDatanodeDescriptors, storagePolicy, flags);
-    if (targets.length < minReplication) {
-      throw new IOException("File " + src + " could only be replicated to "
-          + targets.length + " nodes instead of minReplication (="
-          + minReplication + ").  There are "
-          + getDatanodeManager().getNetworkTopology().getNumOfLeaves()
-          + " datanode(s) running and "
-          + (excludedNodes == null? "no": excludedNodes.size())
-          + " node(s) are excluded in this operation.");
+
+    final String ERROR_MESSAGE = "File %s could only be written to %d of " +
+        "the %d %s. There are %d datanode(s) running and %s "
+        + "node(s) are excluded in this operation.";
+    if (blockType == BlockType.CONTIGUOUS && targets.length < minReplication) {
+      throw new IOException(String.format(ERROR_MESSAGE, src,
+          targets.length, minReplication, "minReplication", minReplication,
+          getDatanodeManager().getNetworkTopology().getNumOfLeaves(),
+          (excludedNodes == null? "no": excludedNodes.size())));
+    } else if (blockType == BlockType.STRIPED &&
+        targets.length < ecPolicy.getNumDataUnits()) {
+      throw new IOException(
+          String.format(ERROR_MESSAGE, src, targets.length,
+              ecPolicy.getNumDataUnits(),
+              String.format("required nodes for %s", ecPolicy.getName()),
+              getDatanodeManager().getNetworkTopology().getNumOfLeaves(),
+              (excludedNodes == null ? "no" : excludedNodes.size())));
     }
     return targets;
   }

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

@@ -201,7 +201,7 @@ class FSDirWriteFileOp {
     }
     storagePolicyID = pendingFile.getStoragePolicyID();
     return new ValidateAddBlockResult(blockSize, numTargets, storagePolicyID,
-                                      clientMachine, blockType);
+                                      clientMachine, blockType, ecPolicy);
   }
 
   static LocatedBlock makeLocatedBlock(FSNamesystem fsn, BlockInfo blk,
@@ -286,7 +286,7 @@ class FSDirWriteFileOp {
     return bm.chooseTarget4NewBlock(src, r.numTargets, clientNode,
                                     excludedNodesSet, r.blockSize,
                                     favoredNodesList, r.storagePolicyID,
-                                    r.blockType, flags);
+                                    r.blockType, r.ecPolicy, flags);
   }
 
   /**
@@ -836,15 +836,23 @@ class FSDirWriteFileOp {
     final byte storagePolicyID;
     final String clientMachine;
     final BlockType blockType;
+    final ErasureCodingPolicy ecPolicy;
 
     ValidateAddBlockResult(
         long blockSize, int numTargets, byte storagePolicyID,
-        String clientMachine, BlockType blockType) {
+        String clientMachine, BlockType blockType,
+        ErasureCodingPolicy ecPolicy) {
       this.blockSize = blockSize;
       this.numTargets = numTargets;
       this.storagePolicyID = storagePolicyID;
       this.clientMachine = clientMachine;
       this.blockType = blockType;
+      this.ecPolicy = ecPolicy;
+
+      if (blockType == BlockType.STRIPED) {
+        Preconditions.checkArgument(ecPolicy != null,
+            "ecPolicy is not specified for striped block");
+      }
     }
   }
 }

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

@@ -42,6 +42,7 @@ import org.apache.hadoop.io.erasurecode.ErasureCodeNative;
 import org.apache.hadoop.io.erasurecode.rawcoder.NativeRSRawErasureCoderFactory;
 import org.apache.hadoop.security.token.Token;
 import org.apache.hadoop.test.GenericTestUtils;
+import org.apache.hadoop.test.LambdaTestUtils;
 import org.apache.hadoop.util.StringUtils;
 import org.apache.log4j.Level;
 import org.junit.Assert;
@@ -282,7 +283,7 @@ public class TestDFSStripedOutputStreamWithFailure {
 
   @Test(timeout = 90000)
   public void testAddBlockWhenNoSufficientDataBlockNumOfNodes()
-      throws IOException {
+      throws Exception {
     HdfsConfiguration conf = new HdfsConfiguration();
     conf.setLong(DFSConfigKeys.DFS_BLOCK_SIZE_KEY, blockSize);
     try {
@@ -301,20 +302,18 @@ public class TestDFSStripedOutputStreamWithFailure {
           DatanodeReportType.LIVE);
       assertEquals("Mismatches number of live Dns ", numDatanodes, info.length);
       final Path dirFile = new Path(dir, "ecfile");
-      FSDataOutputStream out;
-      try {
-        out = dfs.create(dirFile, true);
-        out.write("something".getBytes());
-        out.flush();
-        out.close();
-        Assert.fail("Failed to validate available dns against blkGroupSize");
-      } catch (IOException ioe) {
-        // expected
-        GenericTestUtils.assertExceptionContains("Failed to get " +
-            dataBlocks + " nodes from namenode: blockGroupSize= " +
-            (dataBlocks + parityBlocks) + ", blocks.length= " +
-            numDatanodes, ioe);
-      }
+      LambdaTestUtils.intercept(
+          IOException.class,
+          "File " + dirFile + " could only be written to " +
+              numDatanodes + " of the " + dataBlocks + " required nodes for " +
+              getEcPolicy().getName(),
+          () -> {
+            try (FSDataOutputStream out = dfs.create(dirFile, true)) {
+              out.write("something".getBytes());
+              out.flush();
+            }
+            return 0;
+          });
     } finally {
       tearDown();
     }

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

@@ -175,8 +175,8 @@ public class TestDeadDatanode {
     // choose the targets, but local node should not get selected as this is not
     // part of the cluster anymore
     DatanodeStorageInfo[] results = bm.chooseTarget4NewBlock("/hello", 3,
-        clientNode, new HashSet<Node>(), 256 * 1024 * 1024L, null, (byte) 7,
-        BlockType.CONTIGUOUS, null);
+        clientNode, new HashSet<>(), 256 * 1024 * 1024L, null, (byte) 7,
+        BlockType.CONTIGUOUS, null, null);
     for (DatanodeStorageInfo datanodeStorageInfo : results) {
       assertFalse("Dead node should not be choosen", datanodeStorageInfo
           .getDatanodeDescriptor().equals(clientNode));