Kafka Health Check must be done on offset.storage.replication.factor and not transaction.state.log.replication.factor

[loicmathieu]

Kafka Health Check must be based on offset.storage.replication.factor and not transaction.state.log.replication.factor.

This is a potential issue when using a Kafka cluster with one node as the existing Kafka documentation points out this configuration to be set to '1' and not the other.

I'm agree that both should be set to '1' in case the cluster has only one node, but only the offset setting is set in the existing script provided by Confluent and used in there Docker images.
See https://github.com/confluentinc/cp-docker-images/blob/5.1.2-post/examples/cp-all-in-one/docker-compose.yml for example.

Moreover, if no transaction is used, the transaction topic is not created so this property is useless !

As the fix is easy, I can provide a PR ;)

Task List

• Steps to reproduce provided
• Stacktrace (if present) provided
• Example that reproduces the problem uploaded to Github
• Full description of the issue provided (see below)

Steps to Reproduce

This is easily reproduced by using a simple docker-compose file as following and using it with micronaut-kafka and enabling the health check endpoint

version: '2'
services:
  zookeeper:
    image: confluentinc/cp-zookeeper:5.0.1
    environment:
      - ZOOKEEPER_CLIENT_PORT=2181
  kafka:
    image: confluentinc/cp-kafka:5.0.1
    ports:
        - 9092:9092
    environment:
      - KAFKA_ZOOKEEPER_CONNECT=zookeeper:2181
      - KAFKA_ADVERTISED_LISTENERS=PLAINTEXT://localhost:9092
      - KAFKA_OFFSETS_TOPIC_REPLICATION_FACTOR=1

Expected Behaviour

If we switch to offset.storage.replication.factor instead of transaction.state.log.replication.factor, the kafka health indicator will be Up with the provided docker-compose.

Actual Behaviour

The kafka health indicator is Down with the provided docker-compose.

Environment Information

• Operating System: Windows 10
• Micronaut Version: 1.0.4
• JDK Version: 11

Example Application

Not Provided

[graemerocher]

Seems to duplicate #7

[graemerocher]

@loicmathieu However a PR would be great!

[loicmathieu]

@graemerocher I think my proposal is better than in #7 because the default replication factor can be 3 without any issue on a one node cluster if you specify the replication factory for each topic you created (this is advised anyway).
But a one node cluster cannot works if you don't set the offset replication factor to 1.

I will create a PR for this soon.