openstack/swift
Code Issues Proposed changes

Merge "Save ring builder if dispersion changes"

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This commit is contained in:
Zuul 2017-12-21 06:03:27 +00:00 committed by Gerrit Code Review
commit c29a9b01b9
2 changed files with 116 additions and 3 deletions
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24
swift/cli/ringbuilder.py
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@ -898,7 +898,9 @@ swift-ring-builder <builder_file> rebalance [options]
min_part_seconds_left = builder.min_part_seconds_left
try:
last_balance = builder.get_balance()
last_dispersion = builder.dispersion
parts, balance, removed_devs = builder.rebalance(seed=get_seed(3))
dispersion = builder.dispersion
except exceptions.RingBuilderError as e:
print('-' * 79)
print("An error has occurred during ring validation. Common\n"
@ -922,9 +924,25 @@ swift-ring-builder <builder_file> rebalance [options]
# special value(MAX_BALANCE) until zero weighted device return all
# its partitions. So we cannot check balance has changed.
# Thus we need to check balance or last_balance is special value.
if not options.force and \
not devs_changed and abs(last_balance - balance) < 1 and \
not (last_balance == MAX_BALANCE and balance == MAX_BALANCE):
be_cowardly = True
if options.force:
# User said save it, so we save it.
be_cowardly = False
elif devs_changed:
# We must save if a device changed; this could be something like
# a changed IP address.
be_cowardly = False
else:
# If balance or dispersion changed (presumably improved), then
# we should save to get the improvement.
balance_changed = (
abs(last_balance - balance) >= 1 or
(last_balance == MAX_BALANCE and balance == MAX_BALANCE))
dispersion_changed = abs(last_dispersion - dispersion) >= 1
if balance_changed or dispersion_changed:
be_cowardly = False
if be_cowardly:
print('Cowardly refusing to save rebalance as it did not change '
'at least 1%.')
exit(EXIT_WARNING)

95
test/unit/cli/test_ringbuilder.py
View File

@ -1916,7 +1916,102 @@ class TestCommands(unittest.TestCase, RunSwiftRingBuilderMixin):
ring.save(self.tmpfile)
# Test No change to the device
argv = ["", self.tmpfile, "rebalance", "3"]
with mock.patch('swift.common.ring.RingBuilder.save') as mock_save:
self.assertSystemExit(EXIT_WARNING, ringbuilder.main, argv)
self.assertEqual(len(mock_save.calls), 0)
def test_rebalance_saves_dispersion_improvement(self):
# We set up a situation where dispersion improves but balance
# doesn't. We construct a ring with one zone, then add a second zone
# concurrently with a new device in the first zone. That first
# device won't acquire any partitions, so the ring's balance won't
# change. However, dispersion will improve.
ring = RingBuilder(6, 5, 1)
ring.add_dev({
'region': 1, 'zone': 1,
'ip': '10.0.0.1', 'port': 20001, 'weight': 1000,
'device': 'sda'})
ring.add_dev({
'region': 1, 'zone': 1,
'ip': '10.0.0.1', 'port': 20001, 'weight': 1000,
'device': 'sdb'})
ring.add_dev({
'region': 1, 'zone': 1,
'ip': '10.0.0.1', 'port': 20001, 'weight': 1000,
'device': 'sdc'})
ring.add_dev({
'region': 1, 'zone': 1,
'ip': '10.0.0.1', 'port': 20001, 'weight': 1000,
'device': 'sdd'})
ring.add_dev({
'region': 1, 'zone': 1,
'ip': '10.0.0.1', 'port': 20001, 'weight': 1000,
'device': 'sde'})
ring.rebalance()
# The last guy in zone 1
ring.add_dev({
'region': 1, 'zone': 1,
'ip': '10.0.0.1', 'port': 20001, 'weight': 1000,
'device': 'sdf'})
# Add zone 2 (same total weight as zone 1)
ring.add_dev({
'region': 1, 'zone': 2,
'ip': '10.0.0.2', 'port': 20001, 'weight': 1000,
'device': 'sda'})
ring.add_dev({
'region': 1, 'zone': 2,
'ip': '10.0.0.2', 'port': 20001, 'weight': 1000,
'device': 'sdb'})
ring.add_dev({
'region': 1, 'zone': 2,
'ip': '10.0.0.2', 'port': 20001, 'weight': 1000,
'device': 'sdc'})
ring.add_dev({
'region': 1, 'zone': 2,
'ip': '10.0.0.2', 'port': 20001, 'weight': 1000,
'device': 'sdd'})
ring.add_dev({
'region': 1, 'zone': 2,
'ip': '10.0.0.2', 'port': 20001, 'weight': 1000,
'device': 'sde'})
ring.add_dev({
'region': 1, 'zone': 2,
'ip': '10.0.0.2', 'port': 20001, 'weight': 1000,
'device': 'sdf'})
ring.pretend_min_part_hours_passed()
ring.save(self.tmpfile)
del ring
# Rebalance once: this gets 1/5 replica into zone 2; the ring is
# saved because devices changed.
argv = ["", self.tmpfile, "rebalance", "5759339"]
self.assertSystemExit(EXIT_WARNING, ringbuilder.main, argv)
rb = RingBuilder.load(self.tmpfile)
self.assertEqual(rb.dispersion, 100)
self.assertEqual(rb.get_balance(), 100)
self.run_srb('pretend_min_part_hours_passed')
# Rebalance again: this gets 2/5 replica into zone 2, but no devices
# changed and the balance stays the same. The only improvement is
# dispersion.
captured = {}
def capture_save(rb, path):
captured['dispersion'] = rb.dispersion
captured['balance'] = rb.get_balance()
# The warning is benign; it's just telling the user to keep on
# rebalancing. The important assertion is that the builder was
# saved.
with mock.patch('swift.common.ring.RingBuilder.save', capture_save):
self.assertSystemExit(EXIT_WARNING, ringbuilder.main, argv)
self.assertEqual(captured, {
'dispersion': 0,
'balance': 100,
})
def test_rebalance_no_devices(self):
# Test no devices