Tuning replication factor for sample store

[zkl94]

I have been using strimzi for some time and one thing that is bugging me is this Grafana alert that's been popping up:

After some investigations, I found out these alerts come from strimzi.cruisecontrol.modeltrainingsamples and strimzi.cruisecontrol.partitionmetricsamples, which only have 2 replicas when my default.replication.factor is set to 3.

I also found this issue that is still under discussion and Kate proposed that the replication factor can be tuned by changing sample.store.topic.replication.factor: 1 under CruiseControl.config.

However, after changing the parameter under CruiseControl.config, I am getting the following warnings from the cruise-control pod (which basically says this parameter is incorrect?):

2022-06-30 00:30:23 WARN  ConsumerConfig:380 - The configuration 'sample.store.topic.replication.factor' was supplied but isn't a known config.
2022-06-30 00:30:23 WARN  ProducerConfig:380 - The configuration 'sample.store.topic.replication.factor' was supplied but isn't a known config.
2022-06-30 00:30:24 WARN  AdminClientConfig:380 - The configuration 'sample.store.topic.replication.factor' was supplied but isn't a known config.

the two Kafka topics remain unchanged, using the default upstream config:

kubectl get kafkatopics.kafka.strimzi.io
strimzi.cruisecontrol.modeltrainingsamples                                                         xxxx-ns   32           2                    True
strimzi.cruisecontrol.partitionmetricsamples                                                       xxxx-ns   32           2                    True

I also tried to tune this parameter under Kafka.spec.config and it also doesn't work.

The question is: how should I tune the replication factor for these two topics properly?

[scholzj]

If the topics exist, I doubt changing any settings will change anything. I think you will need to reconfigure them manually.

[zkl94]

I can see the parameters changes after deleting the already-created topics and letting them be recreated automatically