class_docstr: Map nodes to their corresponding logs.
  
  We need to be a little careful here. At an given point in time, node_id <->
  ip can be interchangeably used, but the node_id -> ip relation is not
  bijective _across time_ since IP addresses can be reused. Therefore, we
  should treat node_id as the only unique identifier.
code: def __init__(self):
      # Mapping from node_id -> (ip, node type, stdout_path, process runner)
      self.node_mapping = {}
  
      # A quick, inefficient FIFO cache implementation.
      self.lru_order = []
  
file_path: ray/python/ray/autoscaler/_private/node_tracker.py
imports: from typing import List, Set, Tuple
  from ray.autoscaler._private import constants
label_desc: Use image node_id 1 to create a new NodeTracker object  with example: obj = NodeTracker()