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TreeMap<TaskAttemptID, String> activeTasks; // all last tasks in 2d array should be the active/ running taskmapping from TaskId to GroomServer. // Task to GroomServer relation is recorded by taskId and groom in o.a.h.b.v2.Task.
TreeMap<TaskAttemptID, TaskStatus> taskStatuses// each task should embed with a status object.
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