# Copyright 2013 Hewlett-Packard Development Company, L.P.
# All Rights Reserved.
#
# 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 hashlib
import time
import mock
from oslo_config import cfg
from testtools import matchers
from ironic.common import exception
from ironic.common import hash_ring
from ironic.tests import base
from ironic.tests.unit.db import base as db_base
CONF = cfg.CONF
[docs]class HashRingTestCase(base.TestCase):
# NOTE(deva): the mapping used in these tests is as follows:
# if hosts = [foo, bar]:
# fake -> foo, bar
# if hosts = [foo, bar, baz]:
# fake -> foo, bar, baz
# fake-again -> bar, baz, foo
@mock.patch.object(hashlib, 'md5', autospec=True)
[docs] def test__hash2int_returns_int(self, mock_md5):
CONF.set_override('hash_partition_exponent', 0)
r1 = 32 * 'a'
r2 = 32 * 'b'
mock_md5.return_value.hexdigest.side_effect = [r1, r2]
hosts = ['foo', 'bar']
replicas = 1
ring = hash_ring.HashRing(hosts, replicas=replicas)
self.assertIn(int(r1, 16), ring._host_hashes)
self.assertIn(int(r2, 16), ring._host_hashes)
[docs] def test_create_ring(self):
hosts = ['foo', 'bar']
replicas = 2
ring = hash_ring.HashRing(hosts, replicas=replicas)
self.assertEqual(set(hosts), ring.hosts)
self.assertEqual(replicas, ring.replicas)
[docs] def test_create_with_different_partition_counts(self):
hosts = ['foo', 'bar']
CONF.set_override('hash_partition_exponent', 2)
ring = hash_ring.HashRing(hosts)
self.assertEqual(2 ** 2 * 2, len(ring._partitions))
CONF.set_override('hash_partition_exponent', 8)
ring = hash_ring.HashRing(hosts)
self.assertEqual(2 ** 8 * 2, len(ring._partitions))
CONF.set_override('hash_partition_exponent', 16)
ring = hash_ring.HashRing(hosts)
self.assertEqual(2 ** 16 * 2, len(ring._partitions))
[docs] def test_distribution_one_replica(self):
hosts = ['foo', 'bar', 'baz']
ring = hash_ring.HashRing(hosts, replicas=1)
fake_1_hosts = ring.get_hosts('fake')
fake_2_hosts = ring.get_hosts('fake-again')
# We should have one hosts for each thing
self.assertThat(fake_1_hosts, matchers.HasLength(1))
self.assertThat(fake_2_hosts, matchers.HasLength(1))
# And they must not be the same answers even on this simple data.
self.assertNotEqual(fake_1_hosts, fake_2_hosts)
[docs] def test_distribution_two_replicas(self):
hosts = ['foo', 'bar', 'baz']
ring = hash_ring.HashRing(hosts, replicas=2)
fake_1_hosts = ring.get_hosts('fake')
fake_2_hosts = ring.get_hosts('fake-again')
# We should have two hosts for each thing
self.assertThat(fake_1_hosts, matchers.HasLength(2))
self.assertThat(fake_2_hosts, matchers.HasLength(2))
# And they must not be the same answers even on this simple data
# because if they were we'd be making the active replica a hot spot.
self.assertNotEqual(fake_1_hosts, fake_2_hosts)
[docs] def test_distribution_three_replicas(self):
hosts = ['foo', 'bar', 'baz']
ring = hash_ring.HashRing(hosts, replicas=3)
fake_1_hosts = ring.get_hosts('fake')
fake_2_hosts = ring.get_hosts('fake-again')
# We should have two hosts for each thing
self.assertThat(fake_1_hosts, matchers.HasLength(3))
self.assertThat(fake_2_hosts, matchers.HasLength(3))
# And they must not be the same answers even on this simple data
# because if they were we'd be making the active replica a hot spot.
self.assertNotEqual(fake_1_hosts, fake_2_hosts)
self.assertNotEqual(fake_1_hosts[0], fake_2_hosts[0])
[docs] def test_ignore_hosts(self):
hosts = ['foo', 'bar', 'baz']
ring = hash_ring.HashRing(hosts, replicas=1)
equals_bar_or_baz = matchers.MatchesAny(
matchers.Equals(['bar']),
matchers.Equals(['baz']))
self.assertThat(
ring.get_hosts('fake', ignore_hosts=['foo']),
equals_bar_or_baz)
self.assertThat(
ring.get_hosts('fake', ignore_hosts=['foo', 'bar']),
equals_bar_or_baz)
self.assertEqual([], ring.get_hosts('fake', ignore_hosts=hosts))
[docs] def test_ignore_hosts_with_replicas(self):
hosts = ['foo', 'bar', 'baz']
ring = hash_ring.HashRing(hosts, replicas=2)
self.assertEqual(
set(['bar', 'baz']),
set(ring.get_hosts('fake', ignore_hosts=['foo'])))
self.assertEqual(
set(['baz']),
set(ring.get_hosts('fake', ignore_hosts=['foo', 'bar'])))
self.assertEqual(
set(['baz', 'foo']),
set(ring.get_hosts('fake-again', ignore_hosts=['bar'])))
self.assertEqual(
set(['foo']),
set(ring.get_hosts('fake-again', ignore_hosts=['bar', 'baz'])))
self.assertEqual([], ring.get_hosts('fake', ignore_hosts=hosts))
def _compare_rings(self, nodes, conductors, ring,
new_conductors, new_ring):
delta = {}
mapping = dict((node, ring.get_hosts(node)[0]) for node in nodes)
new_mapping = dict(
(node, new_ring.get_hosts(node)[0]) for node in nodes)
for key, old in mapping.items():
new = new_mapping.get(key, None)
if new != old:
delta[key] = (old, new)
return delta
[docs] def test_rebalance_stability_join(self):
num_conductors = 10
num_nodes = 10000
# Adding 1 conductor to a set of N should move 1/(N+1) of all nodes
# Eg, for a cluster of 10 nodes, adding one should move 1/11, or 9%
# We allow for 1/N to allow for rounding in tests.
redistribution_factor = 1.0 / num_conductors
nodes = [str(x) for x in range(num_nodes)]
conductors = [str(x) for x in range(num_conductors)]
new_conductors = conductors + ['new']
delta = self._compare_rings(
nodes, conductors, hash_ring.HashRing(conductors),
new_conductors, hash_ring.HashRing(new_conductors))
self.assertLess(len(delta), num_nodes * redistribution_factor)
[docs] def test_rebalance_stability_leave(self):
num_conductors = 10
num_nodes = 10000
# Removing 1 conductor from a set of N should move 1/(N) of all nodes
# Eg, for a cluster of 10 nodes, removing one should move 1/10, or 10%
# We allow for 1/(N-1) to allow for rounding in tests.
redistribution_factor = 1.0 / (num_conductors - 1)
nodes = [str(x) for x in range(num_nodes)]
conductors = [str(x) for x in range(num_conductors)]
new_conductors = conductors[:]
new_conductors.pop()
delta = self._compare_rings(
nodes, conductors, hash_ring.HashRing(conductors),
new_conductors, hash_ring.HashRing(new_conductors))
self.assertLess(len(delta), num_nodes * redistribution_factor)
[docs] def test_more_replicas_than_hosts(self):
hosts = ['foo', 'bar']
ring = hash_ring.HashRing(hosts, replicas=10)
self.assertEqual(set(hosts), set(ring.get_hosts('fake')))
[docs] def test_ignore_non_existent_host(self):
hosts = ['foo', 'bar']
ring = hash_ring.HashRing(hosts, replicas=1)
self.assertEqual(['foo'], ring.get_hosts('fake',
ignore_hosts=['baz']))
[docs] def test_create_ring_invalid_data(self):
hosts = None
self.assertRaises(exception.Invalid,
hash_ring.HashRing,
hosts)
[docs] def test_get_hosts_invalid_data(self):
hosts = ['foo', 'bar']
ring = hash_ring.HashRing(hosts)
self.assertRaises(exception.Invalid,
ring.get_hosts,
None)
[docs]class HashRingManagerTestCase(db_base.DbTestCase):
[docs] def setUp(self):
super(HashRingManagerTestCase, self).setUp()
self.ring_manager = hash_ring.HashRingManager()
[docs] def register_conductors(self):
self.dbapi.register_conductor({
'hostname': 'host1',
'drivers': ['driver1', 'driver2'],
})
self.dbapi.register_conductor({
'hostname': 'host2',
'drivers': ['driver1'],
})
[docs] def test_hash_ring_manager_get_ring_success(self):
self.register_conductors()
ring = self.ring_manager['driver1']
self.assertEqual(sorted(['host1', 'host2']), sorted(ring.hosts))
[docs] def test_hash_ring_manager_driver_not_found(self):
self.register_conductors()
self.assertRaises(exception.DriverNotFound,
self.ring_manager.__getitem__,
'driver3')
[docs] def test_hash_ring_manager_no_refresh(self):
# If a new conductor is registered after the ring manager is
# initialized, it won't be seen. Long term this is probably
# undesirable, but today is the intended behavior.
self.assertRaises(exception.DriverNotFound,
self.ring_manager.__getitem__,
'driver1')
self.register_conductors()
self.assertRaises(exception.DriverNotFound,
self.ring_manager.__getitem__,
'driver1')
[docs] def test_hash_ring_manager_refresh(self):
CONF.set_override('hash_ring_reset_interval', 30)
# Initialize the ring manager to make _hash_rings not None, then
# hash ring will refresh only when time interval exceeded.
self.assertRaises(exception.DriverNotFound,
self.ring_manager.__getitem__,
'driver1')
self.register_conductors()
self.ring_manager.updated_at = time.time() - 30
self.ring_manager.__getitem__('driver1')