94 lines
3.2 KiB
Python
94 lines
3.2 KiB
Python
# Copyright 2017 The TensorFlow Authors. All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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# ==============================================================================
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"""Implementation of the SessionRunHook for preemptible Cloud TPUs."""
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from __future__ import absolute_import
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from __future__ import division
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from __future__ import print_function
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import logging as _logging
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import os
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import threading
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import time
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from tensorflow.python.distribute.cluster_resolver import tpu_cluster_resolver
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from tensorflow.python.platform import tf_logging as logging
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from tensorflow.python.training import session_run_hook
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class CloudTPUPreemptedHook(session_run_hook.SessionRunHook):
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"""The SessionRunHook for preemptible Cloud TPUs.
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This is an implementation of SessionRunHook for the pre-emptible Google Cloud
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TPU service. It attempts to close the session if the TPU is preempted, and
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exits the coordinator process if the session cannot be closed.
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"""
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def __init__(self, cluster):
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self._cluster = cluster
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def after_create_session(self, session, coord):
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if tpu_cluster_resolver.is_running_in_gce():
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self._tpu_poller = _TPUPollingThread(self._cluster, session)
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self._tpu_poller.start()
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def end(self, session):
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self._tpu_poller.stop()
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class _TPUPollingThread(threading.Thread):
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"""A thread that polls the state of a TPU node.
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When the node transitions into a TERMINAL state (PREEMPTED, TERMINATED)
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that's considered as not recoverable by the underlying infrastructure,
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it attempts to close the session, and exits the entire process if the
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session.close() stucks.
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"""
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def __init__(self, cluster, session):
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super(_TPUPollingThread, self).__init__()
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self.daemon = True
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self._running = True
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self._session_closed = False
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self._cluster = cluster
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self._session = session
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self._interval = 30
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# Some of the Google API libraries are quite chatty, so disable them.
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for name in ['googleapiclient.discovery', 'oauth2client.client']:
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_logging.getLogger(name).setLevel(_logging.WARNING)
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def stop(self):
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self._running = False
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self._session_closed = True
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self.join()
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def run(self):
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if not tpu_cluster_resolver.is_running_in_gce():
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logging.warning(
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'TPUPollingThread is running in a non-GCE environment, exiting...')
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self._running = False
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return
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while self._running:
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recoverable = self._cluster._cloud_tpu_client.recoverable() # pylint: disable=protected-access
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if not recoverable:
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logging.warning(
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'TPUPollingThread found TPU %s in state %s',
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self._cluster._tpu, self._cluster._cloud_tpu_client.state()) # pylint: disable=protected-access
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os._exit(1) # pylint: disable=protected-access
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time.sleep(self._interval)
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