def get_server(self, request_id):
    return 'default'
Check the 'submit_to' for each MR/Yarn cluster, and return the logical name or host:port of first one that enables submission.
dataset/ETHPy150Open AppScale/appscale/AppServer/google/appengine/api/request_info.py/_LocalRequestInfo.get_server--crossover with--dataset/ETHPy150Open cloudera/hue/desktop/libs/hadoop/src/hadoop/cluster.py/get_cluster_addr_for_job_submission