AMBARI-5661. YARN and MR2 failed to start after upgrade. Default value, if no YARN service. (swagle)

ambari-server/src/main/resources/stacks/HDP/2.0.6/services/YARN/package/scripts/params.py

@@ -105,7 +105,7 @@ yarn_log_aggregation_enabled = config['configurations']['yarn-site']['yarn.log-a
 yarn_nm_app_log_dir =  config['configurations']['yarn-site']['yarn.nodemanager.remote-app-log-dir']
 mapreduce_jobhistory_intermediate_done_dir = config['configurations']['mapred-site']['mapreduce.jobhistory.intermediate-done-dir']
 mapreduce_jobhistory_done_dir = config['configurations']['mapred-site']['mapreduce.jobhistory.done-dir']
-jobhistory_heapsize = config['configurations']['global']['jobhistory_heapsize']
+jobhistory_heapsize = default("/configurations/global/jobhistory_heapsize", "900")
 
 #for create_hdfs_directory
 hostname = config["hostname"]