ironic-python-agent/ironic_python_agent/inspect.py
Julia Kreger 368ab136f0 Add jitter to inspection command reporting
Adds a jitter and backoff behavior to the inspector data
collection command to prevent thundering heard sorts of
issues.

Change-Id: I00517010991cbe43d5958c7d76019ef6fe89c983
2020-03-31 08:13:13 -07:00

126 lines
5.0 KiB
Python

# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import os
import random
import select
import threading
from ironic_lib import exception
from oslo_config import cfg
from oslo_log import log
from ironic_python_agent import errors
from ironic_python_agent import inspector
LOG = log.getLogger(__name__)
class IronicInspection(threading.Thread):
"""Class for manual inspection functionality."""
# If we could wait at most N seconds between heartbeats (or in case of an
# error) we will instead wait r x N seconds, where r is a random value
# between these multipliers.
min_jitter_multiplier = 0.7
max_jitter_multiplier = 1.2
# Exponential backoff values used in case of an error. In reality we will
# only wait a portion of either of these delays based on the jitter
# multipliers.
max_delay = 4 * cfg.CONF.introspection_daemon_post_interval
backoff_factor = 2.7
def __init__(self):
super(IronicInspection, self).__init__()
if bool(cfg.CONF.keyfile) != bool(cfg.CONF.certfile):
LOG.warning("Only one of 'keyfile' and 'certfile' options is "
"defined in config file. Its value will be ignored.")
def _run(self):
try:
daemon_mode = cfg.CONF.introspection_daemon
interval = cfg.CONF.introspection_daemon_post_interval
inspector.inspect()
if not daemon_mode:
# No reason to continue unless we're in daemon mode.
return
self.reader, self.writer = os.pipe()
p = select.poll()
p.register(self.reader)
exception_encountered = False
try:
while daemon_mode:
interval_multiplier = random.uniform(
self.min_jitter_multiplier,
self.max_jitter_multiplier)
interval = interval * interval_multiplier
log_msg = 'sleeping before next inspection, interval: %s'
LOG.info(log_msg, interval)
if p.poll(interval * 1000):
if os.read(self.reader, 1).decode() == 'a':
break
try:
inspector.inspect()
if exception_encountered:
interval = min(
interval,
cfg.CONF.introspection_daemon_post_interval)
exception_encountered = False
except errors.InspectionError as e:
# Failures happen, no reason to exit as
# the failure could be intermittent.
LOG.warning('Error reporting introspection '
'data: %(err)s',
{'err': e})
exception_encountered = True
interval = min(interval * self.backoff_factor,
self.max_delay)
except exception.ServiceLookupFailure as e:
# Likely a mDNS lookup failure. We should
# keep retrying.
LOG.error('Error looking up introspection '
'endpoint: %(err)s',
{'err': e})
exception_encountered = True
interval = min(interval * self.backoff_factor,
self.max_delay)
except Exception as e:
# General failure such as requests ConnectionError
LOG.error('Error occured attempting to connect to '
'connect to the introspection service. '
'Error: %(err)s',
{'err': e})
exception_encountered = True
interval = min(interval * self.backoff_factor,
self.max_delay)
finally:
os.close(self.reader)
os.close(self.writer)
self.reader = None
self.writer = None
except errors.InspectionError as e:
msg = "Inspection failed: %s" % e
raise errors.InspectionError(msg)
def run(self):
"""Run Inspection."""
if not cfg.CONF.inspection_callback_url:
cfg.CONF.set_override('inspection_callback_url', 'mdns')
self._run()