openstack/kolla-ansible
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Set Kafka default replication factor

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This ensures that when using automatic Kafka topic creation, with more than one
node in the Kafka cluster, all partitions in the topic are automatically
replicated. When a single node goes down in a >=3 node cluster, these topics will
continue to accept writes providing there are at least two insync replicas.

In a two node cluster, no failures are tolerated. In a three node cluster, only a
single node failure is tolerated. In a larger cluster the configuration may need
manual tuning.

This configuration follows advice given here:

[1] https://docs.cloudera.com/documentation/kafka/1-2-x/topics/kafka_ha.html#xd_583c10bfdbd326ba-590cb1d1-149e9ca9886--6fec__section_d2t_ff2_lq

Closes-Bug: #1888522

Change-Id: I7d38c6ccb22061aa88d9ac6e2e25c3e095fdb8c3
This commit is contained in:
Doug Szumski 2020-07-22 17:18:26 +01:00
parent 61e32bb131
commit a273e28e20
2 changed files with 12 additions and 0 deletions
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1
ansible/roles/kafka/templates/kafka.server.properties.j2
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@ -8,6 +8,7 @@ socket.receive.buffer.bytes=102400
socket.request.max.bytes=104857600
log.dirs=/var/lib/kafka/data
min.insync.replicas={{ kafka_broker_count if kafka_broker_count|int < 3 else 2 }}
default.replication.factor={{ kafka_broker_count if kafka_broker_count|int < 3 else 3 }}
num.partitions=30
num.recovery.threads.per.data.dir=1
offsets.topic.replication.factor={{ kafka_broker_count if kafka_broker_count|int < 3 else 3 }}

11
releasenotes/notes/improve-kafka-default-topic-replication-0debd5eb89f0c50d.yaml Normal file
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@ -0,0 +1,11 @@
---
fixes:
- |
An issue where when Kafka default topic creation was used to create a
Kafka topic, no redundant replicas were created in a multi-node cluster.
`LP#1888522 <https://launchpad.net/bugs/1888522>`__. This affects Monasca
which uses Kafka, and was previously masked by the legacy Kafka client used
by Monasca which has since been upgraded in Ussuri. Monasca users with
multi-node Kafka clusters should consultant the Kafka `documentation
<https://kafka.apache.org/documentation/>`__ to increase the number of
replicas.