[CORE-135759] Added TopicLeaderReplicaDistributionGoal so we distribute leaders fairly across brokers #20
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added 10 commits
September 5, 2025 11:45
This reverts commit 6daf59b.
eduardagarici
changed the title
ecojan
approved these changes
Sep 25, 2025
| Broker broker) { | ||
| int numTopicLeaders = broker.numLeadersFor(topic); | ||
| int brokerBalanceUpperLimit = broker.isAlive() | ||
| ? _balanceUpperLimitByTopic.get(topic) |
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Not sure if this will ever be the case, but there is a possibility for the get() to return null here
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Not seeing how. The initgoalstate populates those maps for all the topics that it finds. Afterwards, the cluster model does not change between initGoalState and updateGoalState. Did you spot something that I did not see?
dobrerazvan
approved these changes
Oct 2, 2025
added 2 commits
October 7, 2025 16:41
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Starting from linkedin#2267, added slight optimizations and code refactoring.
Summary
Why: In current CC goals, there is no goal to balance a topic leaders only which ensure a fair distribution of load for not log compacted topics. The rebalance looks at historic loads for replica placement and it's possible that load changes temporarily causing load-skew for brokers. A potential solution to this problem is to distribute topic leader partitions fairly across all the brokers.
Avoiding load-skew for brokers is also beneficial for clients that have quotas set up at broker level. Thus, we want to avoid one broker being throttled due to many leaders for a particular topic whilst the other broker remain idle.
What: Add a new Topic Replica Leader distribution goal.
This PR adds a new goal to distribute Leaders Replica for every topic in a fair manner across all the brokers. If the partition count is not a multiple of brokers, some brokers do end up with extra partitions.
The thresholds can be configured using 3 new knobs added to AnalyzerConfig.
The new goal is modeled after existing TopicReplicaDistributionGoal with following differences:
This is a soft goal goal
It looks at leader replicas in a broker only
For candidate brokers with equal number of leader replicas for a topic, it uses total leader replicas as a tie-break
Categorization
Notes:
excludedTopics). But we can configure a set of predefined topics in order to experiment with this goal.