HDDS-291. Initialize hadoop metrics system in standalone hdds datanodes. Contributed by Elek Marton.

hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/HddsDatanodeService.java

@@ -26,6 +26,7 @@ import org.apache.hadoop.hdds.HddsUtils;
 import org.apache.hadoop.hdds.conf.OzoneConfiguration;
 import org.apache.hadoop.hdds.protocol.DatanodeDetails;
 import org.apache.hadoop.hdfs.DFSUtil;
+import org.apache.hadoop.metrics2.lib.DefaultMetricsSystem;
 import org.apache.hadoop.ozone.container.common.helpers.ContainerUtils;
 import org.apache.hadoop.ozone.container.common.statemachine
     .DatanodeStateMachine;
@@ -241,6 +242,7 @@ public class HddsDatanodeService implements ServicePlugin {
         System.exit(1);
       }
       StringUtils.startupShutdownMessage(HddsDatanodeService.class, args, LOG);
+      DefaultMetricsSystem.initialize("HddsDatanode");
       HddsDatanodeService hddsDatanodeService =
           createHddsDatanodeService(conf);
       hddsDatanodeService.start(null);

hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/statemachine/SCMConnectionManager.java

@@ -67,7 +67,7 @@ public class SCMConnectionManager
     this.rpcTimeout = timeOut.intValue();
     this.scmMachines = new HashMap<>();
     this.conf = conf;
-    jmxBean = MBeans.register("OzoneDataNode",
+    jmxBean = MBeans.register("HddsDatanode",
         "SCMConnectionManager",
         this);
   }