Comment 3 for bug 1888522

Reviewed: https://review.opendev.org/742479
Committed: https://git.openstack.org/cgit/openstack/kolla-ansible/commit/?id=a273e28e208eaf7c3d607bff220309ca3b3b0bd7
Submitter: Zuul
Branch: master

commit a273e28e208eaf7c3d607bff220309ca3b3b0bd7
Author: Doug Szumski <email address hidden>
Date: Wed Jul 22 17:18:26 2020 +0100

    Set Kafka default replication factor

    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