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Extend AffinityWeigher to support shards. #306

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Extend AffinityWeigher to support shards. #306

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34 changes: 34 additions & 0 deletions nova/scheduler/weights/affinity.py
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Original file line number Diff line number Diff line change
Expand Up @@ -55,6 +55,7 @@ def _weigh_object(self, host_state, request_spec):
class ServerGroupSoftAffinityWeigher(_SoftAffinityWeigherBase):
policy_name = 'soft-affinity'
warning_sent = False
_SHARD_PREFIX = 'vc-'

def weight_multiplier(self):
if (CONF.filter_scheduler.soft_affinity_weight_multiplier < 0 and
Expand All @@ -70,6 +71,39 @@ def weight_multiplier(self):

return CONF.filter_scheduler.soft_affinity_weight_multiplier

def _weigh_object(self, host_state, request_spec):
weight = super(ServerGroupSoftAffinityWeigher, self)._weigh_object(
host_state, request_spec)

# if the host contained servers from the same group, return that weight
if weight:
return weight

# get shards of the host
host_shard_aggrs = [aggr for aggr in host_state.aggregates
if aggr.name.startswith(self._SHARD_PREFIX)]
if not host_shard_aggrs:
LOG.warning('No aggregates found for host %(host)s.',
{'host': host_state.host})
return 0

if len(host_shard_aggrs) > 1:
LOG.warning('More than one host aggregates found for '
'host %(host)s, selecting first.',
{'host': host_state.host})
host_shard_aggr = host_shard_aggrs[0]

group_hosts = None
if request_spec.instance_group and request_spec.instance_group.hosts:
group_hosts = set(request_spec.instance_group.hosts)
if not group_hosts:
return 0
# group_hosts doesn't contain our host, because otherwise we would
# have returned a weighed already as we would have instances
if group_hosts & set(host_shard_aggr.hosts):
return 0.5
return 0


class ServerGroupSoftAntiAffinityWeigher(_SoftAffinityWeigherBase):
policy_name = 'soft-anti-affinity'
Expand Down
44 changes: 35 additions & 9 deletions nova/tests/unit/scheduler/weights/test_weights_affinity.py
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Original file line number Diff line number Diff line change
Expand Up @@ -29,7 +29,8 @@ def setUp(self):
self.weight_handler = weights.HostWeightHandler()
self.weighers = []

def _get_weighed_host(self, hosts, policy, group='default'):
def _get_weighed_host(self, hosts, policy, group='default',
expected_host=None, match_host=False):
if group == 'default':
members = ['member1', 'member2', 'member3', 'member4', 'member5',
'member6', 'member7']
Expand All @@ -38,17 +39,27 @@ def _get_weighed_host(self, hosts, policy, group='default'):
request_spec = objects.RequestSpec(
instance_group=objects.InstanceGroup(
policy=policy,
members=members))
return self.weight_handler.get_weighed_objects(self.weighers,
hosts,
request_spec)[0]
members=members,
hosts=[h.host for h in hosts]))
hosts = self.weight_handler.get_weighed_objects(self.weighers,
hosts,
request_spec)
if not match_host:
return hosts[0]
else:
for host in hosts:
if host.obj.host == expected_host:
return host

def _get_all_hosts(self):
aggs1 = [objects.Aggregate(id=1, name='vc-a-1', hosts=['host1'])]
aggs2 = [objects.Aggregate(id=2, name='vc-a-2', hosts=['host3']),
objects.Aggregate(id=2, name='vc-a-3', hosts=['host4'])]
host_values = [
('host1', 'node1', {'instances': {
'member1': mock.sentinel,
'instance13': mock.sentinel
}}),
}, 'aggregates': aggs1}),
('host2', 'node2', {'instances': {
'member2': mock.sentinel,
'member3': mock.sentinel,
Expand All @@ -60,12 +71,12 @@ def _get_all_hosts(self):
}}),
('host3', 'node3', {'instances': {
'instance15': mock.sentinel
}}),
}, 'aggregates': aggs2}),
('host4', 'node4', {'instances': {
'member6': mock.sentinel,
'member7': mock.sentinel,
'instance16': mock.sentinel
}})]
}, 'aggregates': aggs2})]
return [fakes.FakeHostState(host, node, values)
for host, node, values in host_values]

Expand Down Expand Up @@ -105,6 +116,20 @@ def test_soft_affinity_weight_multiplier_positive_value(self):
expected_weight=2.0,
expected_host='host2')

def test_soft_affinity_weight_multiplier_same_shards(self):
"""For host, which does not contain servers of server-group,
but in same shard as the servers in the server-group, weight
is 0.5. Due to normalization smallest weight become 0.0
"""
self.flags(soft_affinity_weight_multiplier=2.0,
group='filter_scheduler')
expected_weight = 0.0
hostinfo_list = self._get_all_hosts()
weighed_host = self._get_weighed_host(hostinfo_list,
policy='soft-affinity', group='default',
expected_host='host3', match_host=True)
self.assertEqual(expected_weight, weighed_host.weight)

@mock.patch.object(affinity, 'LOG')
def test_soft_affinity_weight_multiplier_negative_value(self, mock_log):
self.flags(soft_affinity_weight_multiplier=-1.0,
Expand All @@ -116,7 +141,8 @@ def test_soft_affinity_weight_multiplier_negative_value(self, mock_log):
self._do_test(policy='soft-affinity',
expected_weight=0.0,
expected_host='host3')
self.assertEqual(1, mock_log.warning.call_count)
# one from _weigh_object() and two from weight_multiplier()
self.assertEqual(3, mock_log.warning.call_count)

def test_running_twice(self):
"""Run the weighing twice for different groups each run
Expand Down