Automatically refreshing the KafkaRebalance proposal should be properly plugged into the async-flow

[scholzj]

When the KafkaRebalance spec is updated, the KafkaRebalanceAssemblyOperator automatically adds a refresh annotation to it:

strimzi-kafka-operator/cluster-operator/src/main/java/io/strimzi/operator/cluster/operator/assembly/KafkaRebalanceAssemblyOperator.java

Lines 1045 to 1060 in 66ef8d5

	if (kafkaRebalance.getStatus() != null
	&& kafkaRebalance.getStatus().getObservedGeneration() != kafkaRebalance.getMetadata().getGeneration()) {
	KafkaRebalanceBuilder patchedKafkaRebalance = new KafkaRebalanceBuilder(kafkaRebalance);
	patchedKafkaRebalance
	.editMetadata()
	.addToAnnotations(Map.of(ANNO_STRIMZI_IO_REBALANCE, KafkaRebalanceAnnotation.refresh.toString()))
	.endMetadata()
	.editStatus()
	.withObservedGeneration(kafkaRebalance.getMetadata().getGeneration())
	.endStatus();
	kafkaRebalanceOperator.patchAsync(reconciliation, patchedKafkaRebalance.build()).onComplete(
	r -> LOGGER.debugCr(reconciliation, "The KafkaRebalance resource is updated with refresh annotation"));
	}

However, this code seems to be a bit lazily implemented and should be improved:

• As it is done asynchronously, it should be plugged into the asynchronous flow of the Vert.x futures
• It should be done only after the checks for the Kafka cluster, to make sure that:
  • The refresh annotation actually makes sense because the the Kafka cluster exists and is ready
  • Make sure the operator instance annotating it owns the rebalance resource

This should help to avoid race conditions.

[ppatierno]

Not able to join today's call but I think that this should be done.

[scholzj]

Triaged on the Community call on 8.8.2024: This should be fixed.