HDFS-2580. NameNode#main(...) can make use of GenericOptionsParser. Contributed by harsh. (harsh)

(cherry picked from commit 54e612bfb9f877e58f7f153c43cb4147876826d3)

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

@@ -63,6 +63,7 @@ import org.apache.hadoop.tools.GetUserMappingsProtocol;
 import org.apache.hadoop.tracing.SpanReceiverHost;
 import org.apache.hadoop.tracing.TraceAdminProtocol;
 import org.apache.hadoop.util.ExitUtil.ExitException;
+import org.apache.hadoop.util.GenericOptionsParser;
 import org.apache.hadoop.util.JvmPauseMonitor;
 import org.apache.hadoop.util.ServicePlugin;
 import org.apache.hadoop.util.StringUtils;
@@ -1370,6 +1371,10 @@ public class NameNode implements NameNodeStatusMXBean {
     LOG.info("createNameNode " + Arrays.asList(argv));
     if (conf == null)
       conf = new HdfsConfiguration();
+    // Parse out some generic args into Configuration.
+    GenericOptionsParser hParser = new GenericOptionsParser(conf, argv);
+    argv = hParser.getRemainingArgs();
+    // Parse the rest, NN specific args.
     StartupOption startOpt = parseArguments(argv);
     if (startOpt == null) {
       printUsage(System.err);