add task id

src/allreduce_base.cc

@@ -34,6 +34,9 @@ void AllreduceBase::Init(void) {
   // setup from enviroment variables
   {// handling for hadoop
     const char *task_id = getenv("mapred_tip_id");
+    if (task_id == NULL) {
+      task_id = getenv("mapreduce_task_id");
+    }
     if (hadoop_mode != 0) {
       utils::Check(task_id != NULL, "hadoop_mode is set but cannot find mapred_task_id");
     }