def resetDatanode(cls,action):
     datanodes = cls.getDatanodes()
     Machine.resetNode("datanode", datanodes, action)    
 def resetJobtracker(cls,action):
     jobtracker = MAPRED.getJobTracker().split()
     Machine.resetNode("jobtracker", jobtracker, action)
 def resetTasktracker(cls,action):
     tasktrackers = cls.getTasktrackers()
     Machine.resetNode("tasktracker", tasktrackers, action)
 def resetNamenode(cls,action):
     namenode = HDFS.getNamenode().split()
     Machine.resetNode("namenode", namenode, action)