HDFS-15815. if required storageType are unavailable, log the failed reason during choosing Datanode. Contributed by Yang Yun.

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

@@ -81,7 +81,8 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
     NODE_STALE("the node is stale"),
     NODE_TOO_BUSY("the node is too busy"),
     TOO_MANY_NODES_ON_RACK("the rack has too many chosen nodes"),
-    NOT_ENOUGH_STORAGE_SPACE("not enough storage space to place the block");
+    NOT_ENOUGH_STORAGE_SPACE("not enough storage space to place the block"),
+    NO_REQUIRED_STORAGE_TYPE("required storage types are unavailable");
 
     private final String text;
 
@@ -822,6 +823,9 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
             includeType = type;
             break;
           }
+          logNodeIsNotChosen(null,
+              NodeNotChosenReason.NO_REQUIRED_STORAGE_TYPE,
+              " for storage type " + type);
         }
       } else {
         chosenNode = chooseDataNode(scope, excludedNodes);
@@ -958,7 +962,7 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
     if (LOG.isDebugEnabled()) {
       // build the error message for later use.
       debugLoggingBuilder.get()
-          .append("\n  Datanode ").append(node)
+          .append("\n  Datanode ").append((node==null)?"None":node)
           .append(" is not chosen since ").append(reason.getText());
       if (reasonDetails != null) {
         debugLoggingBuilder.get().append(" ").append(reasonDetails);

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/blockmanagement/TestReplicationPolicy.java

@@ -55,6 +55,7 @@ import org.apache.hadoop.hdfs.TestBlockStoragePolicy;
 import org.apache.hadoop.hdfs.protocol.Block;
 import org.apache.hadoop.hdfs.protocol.BlockStoragePolicy;
 import org.apache.hadoop.hdfs.protocol.DatanodeInfo;
+import org.apache.hadoop.hdfs.protocol.HdfsConstants;
 import org.apache.hadoop.hdfs.server.blockmanagement.BlockManager.StatefulBlockInfo;
 import org.apache.hadoop.hdfs.server.common.HdfsServerConstants;
 import org.apache.hadoop.hdfs.server.common.HdfsServerConstants.BlockUCState;
@@ -1648,4 +1649,19 @@ public class TestReplicationPolicy extends BaseReplicationPolicyTest {
 
     assertFalse(bppd.excludeNodeByLoad(node));
   }
-}
+
+  @Test
+  public void testChosenFailureForStorageType() {
+    final LogVerificationAppender appender = new LogVerificationAppender();
+    final Logger logger = Logger.getRootLogger();
+    logger.addAppender(appender);
+
+    DatanodeStorageInfo[] targets = replicator.chooseTarget(filename, 1,
+        dataNodes[0], new ArrayList<DatanodeStorageInfo>(), false, null,
+        BLOCK_SIZE, TestBlockStoragePolicy.POLICY_SUITE.getPolicy(
+            HdfsConstants.StoragePolicy.COLD.value()), null);
+    assertEquals(0, targets.length);
+    assertNotEquals(0,
+        appender.countLinesWithMessage("NO_REQUIRED_STORAGE_TYPE"));
+  }
+}