message: Change timeout thresholds for querying TPU metadata.
diff: @@ -30,8 +30,8 @@ from tensorflow.python.framework import ops
  from tensorflow.python.platform import tf_logging as logging
  from tensorflow.python.tpu import tpu
  -_PINGING_MASTER_TIMEOUT_IN_MS = 60 * 1000 # 1 min
  -_RETRY_TIMES = 120
  +_PINGING_MASTER_TIMEOUT_IN_MS = 5 * 60 * 1000 # 10 min
  +_RETRY_TIMES = 12 * 24 # 1 day
  _INITIAL_TPU_SYSTEM_TIMEOUT_IN_MS = 300 * 1000 # 5 mins
  _TPU_DEVICE_REG = re.compile(r'.*task:(\d+)/.*device:TPU:(\d+)$')
  