diff --git a/tracker/rabit_hadoop.py b/tracker/rabit_hadoop.py
index 8ecb2c04d..ecd05ce1f 100755
--- a/tracker/rabit_hadoop.py
+++ b/tracker/rabit_hadoop.py
@@ -8,6 +8,7 @@ import sys
 import os
 import time
 import subprocess
+import warnings
 import rabit_tracker as tracker
 
 
@@ -26,8 +27,8 @@ if hadoop_home != None:
         assert os.path.exists(hadoop_streaming_jar), "HADDOP_HOME does not contain the haddop streaming jar"
 
 if hadoop_binary == None or hadoop_streaming_jar == None:
-    print 'Warning: Cannot auto-detect path to hadoop and hadoop-streaming jar, need to set them via arguments -hs and -hb'
-    print '\tTo enable auto-detection, you can set enviroment variable HADOOP_HOME or modify rabit_hadoop.py line 14'
+    warnings.warn('Warning: Cannot auto-detect path to hadoop and hadoop-streaming jar, need to set them via arguments -hs and -hb\n'\
+                      '\tTo enable auto-detection, you can set enviroment variable HADOOP_HOME or modify rabit_hadoop.py line 14')
 
 parser = argparse.ArgumentParser(description='Rabit script to submit rabit jobs using Hadoop Streaming.'\
                                      'This script support both Hadoop 1.0 and Yarn(MRv2), Yarn is recommended')
@@ -79,7 +80,17 @@ args = parser.parse_args()
 if args.jobname == 'auto':
     args.jobname = ('Rabit[nworker=%d]:' % args.nworker) + args.command[0].split('/')[-1];
 
-def hadoop_streaming(nworker, worker_args, yarn = False):
+# detech hadoop version
+(out, err) = subprocess.Popen('%s version' % args.hadoop_binary, shell = True, stdout=subprocess.PIPE).communicate()
+out = out.split('\n')[0].split()
+assert out[0] == 'Hadoop', 'cannot parse hadoop version string'
+hadoop_version = out[1].split('.')
+use_yarn = int(hadoop_version[0]) >= 2
+
+if not use_yarn:
+    print 'Current Hadoop Version is %s' % out[1]
+
+def hadoop_streaming(nworker, worker_args, use_yarn):
     fset = set()
     if args.auto_file_cache:
         for i in range(len(args.command)):
@@ -92,7 +103,7 @@ def hadoop_streaming(nworker, worker_args, yarn = False):
                     args.command[i] = args.command[i].split('/')[-1]    
     kmap = {}
     # setup keymaps
-    if yarn:
+    if use_yarn:
         kmap['nworker'] = 'mapreduce.job.maps'
         kmap['jobname'] = 'mapreduce.job.name'
         kmap['nthread'] = 'mapreduce.map.cpu.vcores'
@@ -108,9 +119,11 @@ def hadoop_streaming(nworker, worker_args, yarn = False):
     cmd += ' -D%s=%d' % (kmap['nworker'], nworker)
     cmd += ' -D%s=%s' % (kmap['jobname'], args.jobname)
     if args.nthread != -1:
-        assert kmap['nthread'] is not None, 'nthread can only be set in Yarn(Hadoop 2.x) cluster'\
-            'it is recommended to use Yarn to submit rabit jobs'
-        cmd += ' -D%s=%d' % (kmap['ntread'], args.nthread)
+        if kmap['nthread'] is None:
+            warnings.warn('nthread can only be set in Yarn(Hadoop version greater than 2.0),'\
+                              'it is recommended to use Yarn to submit rabit jobs')
+        else:
+            cmd += ' -D%s=%d' % (kmap['nthread'], args.nthread)
     cmd += ' -D%s=%d' % (kmap['timeout'], args.timeout)
     if args.memory_mb != -1:
         cmd += ' -D%s=%d' % (kmap['timeout'], args.timeout)
@@ -126,6 +139,5 @@ def hadoop_streaming(nworker, worker_args, yarn = False):
     print cmd
     subprocess.check_call(cmd, shell = True)
 
-if __name__ == 'main':
-    fun_submit = lambda nworker, worker_args: hadoop_streaming(nworker, worker_args, yarn=False)
-    tracker.submit(args.nworker, [], fun_submit = fun_submit, verbose = args.verbose)
+fun_submit = lambda nworker, worker_args: hadoop_streaming(nworker, worker_args, int(hadoop_version[0]) >= 2)
+tracker.submit(args.nworker, [], fun_submit = fun_submit, verbose = args.verbose)
diff --git a/tracker/rabit_yarn.py b/tracker/rabit_yarn.py
deleted file mode 100755
index ed80595eb..000000000
--- a/tracker/rabit_yarn.py
+++ /dev/null
@@ -1,10 +0,0 @@
-#!/usr/bin/python
-"""
-This is a script to submit rabit job using Yarn
-submit the rabit process as mappers of MapReduce
-"""
-import rabit_hadoop
-
-if __name__ == 'main':
-    fun_submit = lambda nworker, worker_args: hadoop_streaming(nworker, worker_args, yarn=True)
-    tracker.submit(args.nworker, [], fun_submit = fun_submit, verbose = args.verbose)