def test_rebalance_leaders_unbalanced_case4(self):
# Imbalanced assignment
# Partial leader-imbalance possible
# (Broker: leader-count): {0: 3, 1: 1, 2:0}
# opt-count: 5/3 = 1, extra-count = 2
assignment = dict(
[
((u'T0', 0), ['1', '2']),
((u'T0', 1), ['0', '2']),
((u'T1', 0), ['0']),
((u'T1', 1), ['0']),
((u'T1', 2), ['0']),
]
)
ct = self.build_cluster_topology(assignment, self.srange(3))
_, net_imbal, _ = get_leader_imbalance_stats(ct.brokers.values())
ct.rebalance_leaders()
_, new_net_imbal, new_leaders_per_broker = get_leader_imbalance_stats(
ct.brokers.values(),
)
# Verify that net-imbalance has reduced but not zero
assert new_net_imbal > 0 and new_net_imbal < net_imbal
# Verify the changes in leaders-per-broker count
assert new_leaders_per_broker['2'] == 1
assert new_leaders_per_broker['1'] == 1
assert new_leaders_per_broker['0'] == 3
def test_rebalance_leaders_unbalanced_case4(self):
# Imbalanced assignment
# Partial leader-imbalance possible
# (Broker: leader-count): {0: 3, 1: 1, 2:0}
# opt-count: 5/3 = 1, extra-count = 2
assignment = dict(
[
((u'T0', 0), ['1', '2']),
((u'T0', 1), ['0', '2']),
((u'T1', 0), ['0']),
((u'T1', 1), ['0']),
((u'T1', 2), ['0']),
]
)
ct = self.build_cluster_topology(assignment, self.srange(3))
_, net_imbal, _ = get_leader_imbalance_stats(ct.brokers.values())
ct.rebalance_leaders()
_, new_net_imbal, new_leaders_per_broker = get_leader_imbalance_stats(
ct.brokers.values(),
)
# Verify that net-imbalance has reduced but not zero
assert new_net_imbal > 0 and new_net_imbal < net_imbal
# Verify the changes in leaders-per-broker count
assert new_leaders_per_broker['2'] == 1
assert new_leaders_per_broker['1'] == 1
assert new_leaders_per_broker['0'] == 3
def test_rebalance_leaders_unbalanced_case1(self):
# Balance leader-imbalance successfully
# (broker-id: leader-count): {0: 0, 1:2, 2:1}
# Net-leader-imbalance: 1
# opt-count: 3/3 = 1, extra-count: 3%3 = 0
assignment = dict(
[
((u'T0', 0), ['1', '2']),
((u'T0', 1), ['2', '0']),
((u'T1', 0), ['1', '0']),
]
)
ct = self.build_cluster_topology(assignment, self.srange(3))
orig_assignment = ct.assignment
ct.rebalance_leaders()
# Verify if valid-leader assignment
self.assert_leader_valid(orig_assignment, ct.assignment)
# New-leader imbalance-count be less than previous imbal count
_, new_leader_imbal, new_leaders_per_broker = \
get_leader_imbalance_stats(ct.brokers.values())
# Verify leader-balanced
assert new_leader_imbal == 0
# Verify partitions-changed assignment
assert new_leaders_per_broker['0'] == 1
assert new_leaders_per_broker['1'] == 1
assert new_leaders_per_broker['2'] == 1
def test_rebalance_leaders_unbalanced_case1(self):
# Balance leader-imbalance successfully
# (broker-id: leader-count): {0: 0, 1:2, 2:1}
# Net-leader-imbalance: 1
# opt-count: 3/3 = 1, extra-count: 3%3 = 0
assignment = dict(
[
((u'T0', 0), ['1', '2']),
((u'T0', 1), ['2', '0']),
((u'T1', 0), ['1', '0']),
]
)
ct = self.build_cluster_topology(assignment, self.srange(3))
orig_assignment = ct.assignment
ct.rebalance_leaders()
# Verify if valid-leader assignment
self.assert_leader_valid(orig_assignment, ct.assignment)
# New-leader imbalance-count be less than previous imbal count
_, new_leader_imbal, new_leaders_per_broker = \
get_leader_imbalance_stats(ct.brokers.values())
# Verify leader-balanced
assert new_leader_imbal == 0
# Verify partitions-changed assignment
assert new_leaders_per_broker['0'] == 1
assert new_leaders_per_broker['1'] == 1
assert new_leaders_per_broker['2'] == 1
def test_rebalance_leaders_unbalanced_case2b(self):
assignment = dict(
[
((u'T0', 0), ['3', '2']),
((u'T1', 0), ['1', '2']),
((u'T1', 1), ['0', '1']),
((u'T2', 0), ['0']),
]
)
ct = self.build_cluster_topology(assignment, self.srange(4))
ct.rebalance_leaders()
# Verify leader-balanced
_, leader_imbal, _ = get_leader_imbalance_stats(ct.brokers.values())
assert leader_imbal == 0
def test_rebalance_leaders_unbalanced_case2b(self):
assignment = dict(
[
((u'T0', 0), ['3', '2']),
((u'T1', 0), ['1', '2']),
((u'T1', 1), ['0', '1']),
((u'T2', 0), ['0']),
]
)
ct = self.build_cluster_topology(assignment, self.srange(4))
ct.rebalance_leaders()
# Verify leader-balanced
_, leader_imbal, _ = get_leader_imbalance_stats(ct.brokers.values())
assert leader_imbal == 0
def test_rebalance_leaders_unbalanced_case3(self):
# Imbalanced 0 and 2. No re-balance possible.
assignment = dict(
[
((u'T1', 0), ['1', '2']),
((u'T1', 1), ['0']),
((u'T2', 0), ['0']),
]
)
ct = self.build_cluster_topology(assignment, self.srange(3))
ct.rebalance_leaders()
# Verify still leader-imbalanced
_, leader_imbal, _ = get_leader_imbalance_stats(ct.brokers.values())
assert leader_imbal == 1
# No change in assignment
assert sorted(ct.assignment) == sorted(assignment)
def test_rebalance_leaders_unbalanced_case3(self):
# Imbalanced 0 and 2. No re-balance possible.
assignment = dict(
[
((u'T1', 0), ['1', '2']),
((u'T1', 1), ['0']),
((u'T2', 0), ['0']),
]
)
ct = self.build_cluster_topology(assignment, self.srange(3))
ct.rebalance_leaders()
# Verify still leader-imbalanced
_, leader_imbal, _ = get_leader_imbalance_stats(ct.brokers.values())
assert leader_imbal == 1
# No change in assignment
assert sorted(ct.assignment) == sorted(assignment)
def test_rebalance_leaders_unbalanced_case2(self):
# (Broker: leader-count): {0: 2, 1: 1, 2:0}
# opt-count: 3/3 = 1, extra-count = 0
# Leader-imbalance-value: 1
assignment = dict(
[
((u'T0', 0), ['1', '2']),
((u'T1', 1), ['0', '1']),
((u'T1', 0), ['0']),
]
)
ct = self.build_cluster_topology(assignment, self.srange(3))
ct.rebalance_leaders()
# Verify leader-balanced
_, leader_imbal, _ = get_leader_imbalance_stats(ct.brokers.values())
assert leader_imbal == 0
def test_rebalance_leaders_unbalanced_case2(self):
# (Broker: leader-count): {0: 2, 1: 1, 2:0}
# opt-count: 3/3 = 1, extra-count = 0
# Leader-imbalance-value: 1
assignment = dict(
[
((u'T0', 0), ['1', '2']),
((u'T1', 1), ['0', '1']),
((u'T1', 0), ['0']),
]
)
ct = self.build_cluster_topology(assignment, self.srange(3))
ct.rebalance_leaders()
# Verify leader-balanced
_, leader_imbal, _ = get_leader_imbalance_stats(ct.brokers.values())
assert leader_imbal == 0
def test_rebalance_leaders_unbalanced_case5(self):
# Special case, wherein none under-balanced
# but 0 is overbalanced
assignment = dict(
[
((u'T1', 1), ['0', '1']),
((u'T2', 0), ['0']),
((u'T2', 1), ['0']),
((u'T3', 0), ['2', '3']),
((u'T3', 1), ['3', '1']),
((u'T4', 0), ['1']),
]
)
ct = self.build_cluster_topology(assignment, self.srange(4))
ct.rebalance_leaders()
# Verify leader-balanced
_, leader_imbal, _ = get_leader_imbalance_stats(ct.brokers.values())
assert leader_imbal == 0
def test_rebalance_leaders_unbalanced_case2d(self):
# Broker-2 imbalanced with same brokers
# Broker-2 requests leadership from same broker-1 twice
assignment = dict(
[
((u'T1', 0), ['1', '2']),
((u'T1', 1), ['0', '1']),
((u'T1', 2), ['0']),
((u'T1', 3), ['1', '2']),
((u'T1', 4), ['0', '1']),
((u'T1', 5), ['0']),
]
)
ct = self.build_cluster_topology(assignment, self.srange(3))
ct.rebalance_leaders()
# Verify leader-balanced
_, leader_imbal, _ = get_leader_imbalance_stats(ct.brokers.values())
assert leader_imbal == 0
def test_rebalance_leaders_balanced_case2(self):
# Already balanced-assignment NOT evenly-distributed
# (broker-id: leader-count): {0: 1, 1:1, 2:1}
# opt-count: 2/3 = 0, extra-count: 2%3 = 2
assignment = dict(
[
((u'T0', 0), ['1', '2']),
((u'T0', 1), ['2', '0']),
]
)
ct = self.build_cluster_topology(assignment, self.srange(3))
orig_assignment = ct.assignment
ct.rebalance_leaders()
_, net_imbal, _ = get_leader_imbalance_stats(ct.brokers.values())
# No changed in already-balanced assignment
assert orig_assignment == ct.assignment
# Assert leader-balanced
assert net_imbal == 0
def test_rebalance_leaders_unbalanced_case5(self):
# Special case, wherein none under-balanced
# but 0 is overbalanced
assignment = dict(
[
((u'T1', 1), ['0', '1']),
((u'T2', 0), ['0']),
((u'T2', 1), ['0']),
((u'T3', 0), ['2', '3']),
((u'T3', 1), ['3', '1']),
((u'T4', 0), ['1']),
]
)
ct = self.build_cluster_topology(assignment, self.srange(4))
ct.rebalance_leaders()
# Verify leader-balanced
_, leader_imbal, _ = get_leader_imbalance_stats(ct.brokers.values())
assert leader_imbal == 0
def test_rebalance_leaders_balanced_case2(self):
# Already balanced-assignment NOT evenly-distributed
# (broker-id: leader-count): {0: 1, 1:1, 2:1}
# opt-count: 2/3 = 0, extra-count: 2%3 = 2
assignment = dict(
[
((u'T0', 0), ['1', '2']),
((u'T0', 1), ['2', '0']),
]
)
ct = self.build_cluster_topology(assignment, self.srange(3))
orig_assignment = ct.assignment
ct.rebalance_leaders()
_, net_imbal, _ = get_leader_imbalance_stats(ct.brokers.values())
# No changed in already-balanced assignment
assert orig_assignment == ct.assignment
# Assert leader-balanced
assert net_imbal == 0
def test_rebalance_leaders_unbalanced_case2d(self):
# Broker-2 imbalanced with same brokers
# Broker-2 requests leadership from same broker-1 twice
assignment = dict(
[
((u'T1', 0), ['1', '2']),
((u'T1', 1), ['0', '1']),
((u'T1', 2), ['0']),
((u'T1', 3), ['1', '2']),
((u'T1', 4), ['0', '1']),
((u'T1', 5), ['0']),
]
)
ct = self.build_cluster_topology(assignment, self.srange(3))
ct.rebalance_leaders()
# Verify leader-balanced
_, leader_imbal, _ = get_leader_imbalance_stats(ct.brokers.values())
assert leader_imbal == 0
def test_rebalance_leaders_unbalanced_case2e(self):
# Imbalance-val 2
# Multiple imbalanced brokers (2, 5) gets non-follower balanced
# from multiple brokers (1,4)
assignment = dict(
[
((u'T1', 0), ['1', '2']),
((u'T1', 1), ['0', '1']),
((u'T2', 0), ['0']),
((u'T3', 0), ['4', '5']),
((u'T3', 1), ['3', '4']),
((u'T4', 0), ['3']),
]
)
ct = self.build_cluster_topology(assignment, self.srange(6))
ct.rebalance_leaders()
# Verify leader-balanced
_, leader_imbal, _ = get_leader_imbalance_stats(ct.brokers.values())
assert leader_imbal == 0
def test_rebalance_leaders_unbalanced_case2e(self):
# Imbalance-val 2
# Multiple imbalanced brokers (2, 5) gets non-follower balanced
# from multiple brokers (1,4)
assignment = dict(
[
((u'T1', 0), ['1', '2']),
((u'T1', 1), ['0', '1']),
((u'T2', 0), ['0']),
((u'T3', 0), ['4', '5']),
((u'T3', 1), ['3', '4']),
((u'T4', 0), ['3']),
]
)
ct = self.build_cluster_topology(assignment, self.srange(6))
ct.rebalance_leaders()
# Verify leader-balanced
_, leader_imbal, _ = get_leader_imbalance_stats(ct.brokers.values())
assert leader_imbal == 0
def test_rebalance_leaders_unbalanced_case2c(self):
# Broker-2 imbalance value: 2 with different brokers
# Broker-2 requests leadership from multiple brokers (0, 1) once
assignment = dict(
[
((u'T1', 0), ['1', '2']),
((u'T1', 1), ['0', '1']),
((u'T2', 0), ['0']),
((u'T2', 1), ['0']),
((u'T3', 0), ['3', '2']),
((u'T3', 1), ['1', '3']),
((u'T4', 0), ['1']),
((u'T4', 2), ['3']),
]
)
ct = self.build_cluster_topology(assignment, self.srange(4))
ct.rebalance_leaders()
# Verify leader-balanced
_, leader_imbal, _ = get_leader_imbalance_stats(ct.brokers.values())
assert leader_imbal == 0
def test_rebalance_leaders_unbalanced_case2c(self):
# Broker-2 imbalance value: 2 with different brokers
# Broker-2 requests leadership from multiple brokers (0, 1) once
assignment = dict(
[
((u'T1', 0), ['1', '2']),
((u'T1', 1), ['0', '1']),
((u'T2', 0), ['0']),
((u'T2', 1), ['0']),
((u'T3', 0), ['3', '2']),
((u'T3', 1), ['1', '3']),
((u'T4', 0), ['1']),
((u'T4', 2), ['3']),
]
)
ct = self.build_cluster_topology(assignment, self.srange(4))
ct.rebalance_leaders()
# Verify leader-balanced
_, leader_imbal, _ = get_leader_imbalance_stats(ct.brokers.values())
assert leader_imbal == 0
def test_rebalance_leaders_unbalanced_case2a(self):
# (Broker: leader-count): {0: 2, 1: 1, 2:0, 3:1}
# opt-count: 3/4 = 1, extra-count = 3
# Leader-imbalance-value: 1
# imbalanced-broker: 0,2; balanced-brokers: 1,3
assignment = dict(
[
((u'T0', 0), ['3', '2']),
((u'T0', 1), ['1', '3']),
((u'T1', 1), ['0', '1']),
((u'T1', 0), ['0']),
]
)
ct = self.build_cluster_topology(assignment, self.srange(4))
ct.rebalance_leaders()
# Verify balanced
_, leader_imbal, _ = get_leader_imbalance_stats(ct.brokers.values())
assert leader_imbal == 0
# Verify that (T0, 1) also swapped even if 1 and 3 were balanced
# Rebalancing through non-followers
replica_ids = [b.id for b in ct.partitions[('T0', 1)].replicas]
assert replica_ids == ['3', '1']
def test_rebalance_leaders_unbalanced_case2a(self):
# (Broker: leader-count): {0: 2, 1: 1, 2:0, 3:1}
# opt-count: 3/4 = 1, extra-count = 3
# Leader-imbalance-value: 1
# imbalanced-broker: 0,2; balanced-brokers: 1,3
assignment = dict(
[
((u'T0', 0), ['3', '2']),
((u'T0', 1), ['1', '3']),
((u'T1', 1), ['0', '1']),
((u'T1', 0), ['0']),
]
)
ct = self.build_cluster_topology(assignment, self.srange(4))
ct.rebalance_leaders()
# Verify balanced
_, leader_imbal, _ = get_leader_imbalance_stats(ct.brokers.values())
assert leader_imbal == 0
# Verify that (T0, 1) also swapped even if 1 and 3 were balanced
# Rebalancing through non-followers
replica_ids = [b.id for b in ct.partitions[('T0', 1)].replicas]
assert replica_ids == ['3', '1']
