HDFS-15448. Remove duplicate BlockPoolManager starting when run DataNode. Contriubted by jianghua zhu.

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

@@ -2710,7 +2710,11 @@ public class DataNode extends ReconfigurableBase
    *  If this thread is specifically interrupted, it will stop waiting.
    */
   public void runDatanodeDaemon() throws IOException {
-    blockPoolManager.startAll();
+
+    // Verify that blockPoolManager has been started.
+    if (!isDatanodeUp()) {
+      throw new IOException("Failed to instantiate DataNode.");
+    }
 
     // start dataXceiveServer
     dataXceiverServer.start();

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/TestDataNodeExit.java

@@ -82,6 +82,17 @@ public class TestDataNodeExit {
         dn.getBpOsCount());
   }
 
+  @Test
+  public void testBPServiceState() {
+    List<DataNode> dataNodes = cluster.getDataNodes();
+    for (DataNode dataNode : dataNodes) {
+      List<BPOfferService> bposList = dataNode.getAllBpOs();
+      for (BPOfferService bpOfferService : bposList) {
+        assertTrue(bpOfferService.isAlive());
+      }
+    }
+  }
+
   /**
    * Test BPService Thread Exit
    */