openstack/swift
Code Issues Proposed changes
93ca16c558
swift/test/probe/test_reconstructor_rebuild.py
Alistair Coles 6574ce31ee EC: reconstruct using non-durable fragments 
Previously the reconstructor would only reconstruct a missing fragment
when a set of ec_ndata other fragments was available, *all* of which
were durable. Since change [1] it has been possible to retrieve
non-durable fragments from object servers. This patch changes the
reconstructor to take advantage of [1] and use non-durable fragments.

A new probe test is added to test scenarios with a mix of failed and
non-durable nodes. The existing probe tests in
test_reconstructor_rebuild.py and test_reconstructor_durable.py were
broken. These were intended to simulate cases where combinations of
nodes were either failed or had non-durable fragments, but the test
scenarios defined were not actually created - every test scenario
broke only one node instead of the intent of breaking multiple
nodes. The existing tests have been refactored to re-use most of their
setup and assertion code, and merged with the new test into a single
class in test_reconstructor_rebuild.py.

test_reconstructor_durable.py is removed.

[1] Related-Change: I2310981fd1c4622ff5d1a739cbcc59637ffe3fc3

Change-Id: Ic0cdbc7cee657cea0330c2eb1edabe8eb52c0567
Co-Authored-By: Clay Gerrard <clay.gerrard@gmail.com>
Closes-Bug: #1624088
2016-11-03 16:54:09 +00:00

330 lines
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Python
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#!/usr/bin/python -u
# Copyright (c) 2010-2012 OpenStack Foundation
#
# 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 errno
import json
from contextlib import contextmanager
from hashlib import md5
import unittest
import uuid
import shutil
import random
from collections import defaultdict
import os
from test.probe.common import ECProbeTest
from swift.common import direct_client
from swift.common.storage_policy import EC_POLICY
from swift.common.manager import Manager
from swift.obj.reconstructor import _get_partners
from swiftclient import client, ClientException
class Body(object):
def __init__(self, total=3.5 * 2 ** 20):
self.total = total
self.hasher = md5()
self.size = 0
self.chunk = 'test' * 16 * 2 ** 10
@property
def etag(self):
return self.hasher.hexdigest()
def __iter__(self):
return self
def next(self):
if self.size > self.total:
raise StopIteration()
self.size += len(self.chunk)
self.hasher.update(self.chunk)
return self.chunk
def __next__(self):
return next(self)
class TestReconstructorRebuild(ECProbeTest):
def setUp(self):
super(TestReconstructorRebuild, self).setUp()
self.container_name = 'container-%s' % uuid.uuid4()
self.object_name = 'object-%s' % uuid.uuid4()
# sanity
self.assertEqual(self.policy.policy_type, EC_POLICY)
self.reconstructor = Manager(["object-reconstructor"])
# create EC container
headers = {'X-Storage-Policy': self.policy.name}
client.put_container(self.url, self.token, self.container_name,
headers=headers)
# PUT object and POST some metadata
contents = Body()
headers = {'x-object-meta-foo': 'meta-foo'}
self.headers_post = {'x-object-meta-bar': 'meta-bar'}
self.etag = client.put_object(self.url, self.token,
self.container_name,
self.object_name,
contents=contents, headers=headers)
client.post_object(self.url, self.token, self.container_name,
self.object_name, headers=dict(self.headers_post))
self.opart, self.onodes = self.object_ring.get_nodes(
self.account, self.container_name, self.object_name)
# stash frag etags and metadata for later comparison
self.frag_headers, self.frag_etags = self._assert_all_nodes_have_frag()
for node_index, hdrs in self.frag_headers.items():
# sanity check
self.assertIn(
'X-Backend-Durable-Timestamp', hdrs,
'Missing durable timestamp in %r' % self.frag_headers)
def proxy_get(self):
# GET object
headers, body = client.get_object(self.url, self.token,
self.container_name,
self.object_name,
resp_chunk_size=64 * 2 ** 10)
resp_checksum = md5()
for chunk in body:
resp_checksum.update(chunk)
return headers, resp_checksum.hexdigest()
def direct_get(self, node, part, require_durable=True):
req_headers = {'X-Backend-Storage-Policy-Index': int(self.policy)}
if not require_durable:
req_headers.update(
{'X-Backend-Fragment-Preferences': json.dumps([])})
headers, data = direct_client.direct_get_object(
node, part, self.account, self.container_name,
self.object_name, headers=req_headers,
resp_chunk_size=64 * 2 ** 20)
hasher = md5()
for chunk in data:
hasher.update(chunk)
return headers, hasher.hexdigest()
def _break_nodes(self, failed, non_durable):
# delete partitions on the failed nodes and remove durable marker from
# non-durable nodes
for i, node in enumerate(self.onodes):
part_dir = self.storage_dir('object', node, part=self.opart)
if i in failed:
shutil.rmtree(part_dir, True)
try:
self.direct_get(node, self.opart)
except direct_client.DirectClientException as err:
self.assertEqual(err.http_status, 404)
elif i in non_durable:
for dirs, subdirs, files in os.walk(part_dir):
for fname in files:
if fname.endswith('.data'):
non_durable_fname = fname.replace('#d', '')
os.rename(os.path.join(dirs, fname),
os.path.join(dirs, non_durable_fname))
break
headers, etag = self.direct_get(node, self.opart,
require_durable=False)
self.assertNotIn('X-Backend-Durable-Timestamp', headers)
try:
os.remove(os.path.join(part_dir, 'hashes.pkl'))
except OSError as e:
if e.errno != errno.ENOENT:
raise
def _format_node(self, node):
return '%s#%s' % (node['device'], node['index'])
def _assert_all_nodes_have_frag(self):
# check all frags are in place
failures = []
frag_etags = {}
frag_headers = {}
for node in self.onodes:
try:
headers, etag = self.direct_get(node, self.opart)
frag_etags[node['index']] = etag
del headers['Date'] # Date header will vary so remove it
frag_headers[node['index']] = headers
except direct_client.DirectClientException as err:
failures.append((node, err))
if failures:
self.fail('\n'.join([' Node %r raised %r' %
(self._format_node(node), exc)
for (node, exc) in failures]))
return frag_headers, frag_etags
@contextmanager
def _annotate_failure_with_scenario(self, failed, non_durable):
try:
yield
except (AssertionError, ClientException) as err:
self.fail(
'Scenario with failed nodes: %r, non-durable nodes: %r\n'
' failed with:\n%s' %
([self._format_node(self.onodes[n]) for n in failed],
[self._format_node(self.onodes[n]) for n in non_durable], err)
)
def _test_rebuild_scenario(self, failed, non_durable,
reconstructor_cycles):
# helper method to test a scenario with some nodes missing their
# fragment and some nodes having non-durable fragments
with self._annotate_failure_with_scenario(failed, non_durable):
self._break_nodes(failed, non_durable)
# make sure we can still GET the object and it is correct; the
# proxy is doing decode on remaining fragments to get the obj
with self._annotate_failure_with_scenario(failed, non_durable):
headers, etag = self.proxy_get()
self.assertEqual(self.etag, etag)
for key in self.headers_post:
self.assertIn(key, headers)
self.assertEqual(self.headers_post[key], headers[key])
# fire up reconstructor
for i in range(reconstructor_cycles):
self.reconstructor.once()
# check GET via proxy returns expected data and metadata
with self._annotate_failure_with_scenario(failed, non_durable):
headers, etag = self.proxy_get()
self.assertEqual(self.etag, etag)
for key in self.headers_post:
self.assertIn(key, headers)
self.assertEqual(self.headers_post[key], headers[key])
# check all frags are intact, durable and have expected metadata
with self._annotate_failure_with_scenario(failed, non_durable):
frag_headers, frag_etags = self._assert_all_nodes_have_frag()
self.assertEqual(self.frag_etags, frag_etags)
# self._frag_headers include X-Backend-Durable-Timestamp so this
# assertion confirms that the rebuilt frags are all durable
self.assertEqual(self.frag_headers, frag_headers)
def test_rebuild_missing_frags(self):
# build up a list of node lists to kill data from,
# first try a single node
# then adjacent nodes and then nodes >1 node apart
single_node = (random.randint(0, 5),)
adj_nodes = (0, 5)
far_nodes = (0, 4)
for failed_nodes in [single_node, adj_nodes, far_nodes]:
self._test_rebuild_scenario(failed_nodes, [], 1)
def test_rebuild_non_durable_frags(self):
# build up a list of node lists to make non-durable,
# first try a single node
# then adjacent nodes and then nodes >1 node apart
single_node = (random.randint(0, 5),)
adj_nodes = (0, 5)
far_nodes = (0, 4)
for non_durable_nodes in [single_node, adj_nodes, far_nodes]:
self._test_rebuild_scenario([], non_durable_nodes, 1)
def test_rebuild_with_missing_frags_and_non_durable_frags(self):
# pick some nodes with parts deleted, some with non-durable fragments
scenarios = [
# failed, non-durable
((0, 2), (4,)),
((0, 4), (2,)),
]
for failed, non_durable in scenarios:
self._test_rebuild_scenario(failed, non_durable, 3)
scenarios = [
# failed, non-durable
((0, 1), (2,)),
((0, 2), (1,)),
]
for failed, non_durable in scenarios:
# why 2 repeats? consider missing fragment on nodes 0, 1 and
# missing durable on node 2: first reconstructor cycle on node 3
# will make node 2 durable, first cycle on node 5 will rebuild on
# node 0; second cycle on node 0 or 2 will rebuild on node 1. Note
# that it is possible, that reconstructor processes on each node
# run in order such that all rebuild complete in once cycle, but
# that is not guaranteed, we allow 2 cycles to be sure.
self._test_rebuild_scenario(failed, non_durable, 2)
scenarios = [
# failed, non-durable
((0, 2), (1, 3, 5)),
((0,), (1, 2, 4, 5)),
]
for failed, non_durable in scenarios:
# why 3 repeats? consider missing fragment on node 0 and single
# durable on node 3: first reconstructor cycle on node 3 will make
# nodes 2 and 4 durable, second cycle on nodes 2 and 4 will make
# node 1 and 5 durable, third cycle on nodes 1 or 5 will
# reconstruct the missing fragment on node 0.
self._test_rebuild_scenario(failed, non_durable, 3)
def test_rebuild_partner_down(self):
# find a primary server that only has one of it's devices in the
# primary node list
group_nodes_by_config = defaultdict(list)
for n in self.onodes:
group_nodes_by_config[self.config_number(n)].append(n)
for config_number, node_list in group_nodes_by_config.items():
if len(node_list) == 1:
break
else:
self.fail('ring balancing did not use all available nodes')
primary_node = node_list[0]
# pick one it's partners to fail randomly
partner_node = random.choice(_get_partners(
primary_node['index'], self.onodes))
# 507 the partner device
device_path = self.device_dir('object', partner_node)
self.kill_drive(device_path)
# select another primary sync_to node to fail
failed_primary = [n for n in self.onodes if n['id'] not in
(primary_node['id'], partner_node['id'])][0]
# ... capture it's fragment etag
failed_primary_meta, failed_primary_etag = self.direct_get(
failed_primary, self.opart)
# ... and delete it
part_dir = self.storage_dir('object', failed_primary, part=self.opart)
shutil.rmtree(part_dir, True)
# reconstruct from the primary, while one of it's partners is 507'd
self.reconstructor.once(number=self.config_number(primary_node))
# the other failed primary will get it's fragment rebuilt instead
failed_primary_meta_new, failed_primary_etag_new = self.direct_get(
failed_primary, self.opart)
del failed_primary_meta['Date']
del failed_primary_meta_new['Date']
self.assertEqual(failed_primary_etag, failed_primary_etag_new)
self.assertEqual(failed_primary_meta, failed_primary_meta_new)
# just to be nice
self.revive_drive(device_path)
if __name__ == "__main__":
unittest.main()
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