Is KafkaTopicOperator enabled by default?

[jslusher]

I have a strimzi Kafka cluster and I can see several KafkaTopics in the output of kubectl get kafkatopic, but I don't have the topic operator enabled as far as I know. I don't see a topic-operator pod either. Is it enabled whether I want it or not?

[scholzj]

The Topic Operator is enabled by having the .spec.entityOperator.topicOperator section in the Kafka CR. Having it there will have the Topic Operator start (the pod will be actually named ...-entity-operator and the Topic Operator is just one of its containers).

But the KafkaTopic CRD is installed independently on it with the Strimzi Cluster Operator. So even if you haven't enabled the Topic Operator, you might create the KafkaTopic resources. But they will be ignored as there will be nobody to pick them up.

[jslusher]

I see now that I have .spec.entityOperator.topicOperator configured with logging and resources in my Kafka resource. I missed when I looked before because I was looking for topic-operator. I might have also been looking for it in my operator config and not on the Kafka resource itself. Anyway, found it, thanks!

[jslusher]

@scholzj I have a followup question about this. My strimzi operator started around version 0.23.0 or so, which means originally we were using the BTO. We're now using version 0.42.0. I see this in your UTO blog post, in the section on upgrading to UTO from BTO:

The plan is to move it to beta in Strimzi 0.39.0, where it will be enabled by default.

Does that mean that we're already using UTO or do I still need to set STRIMZI_FEATURE_GATES="+UnidirectionalTopicOperator" to make the switch?

I'm also wondering if I should just remove the topic-operator altogether if we don't plan on using the KafkaTopic resource. Currently we do not have any KafkaTopic resources that weren't created automatically by the operator.

[scholzj]

Once you disable it (and once the Pod / Container is deleted!), they would be ignored. But you should probably consider deleting them I guess as they would be no longer needed.

[jslusher]

I removed my topic-operator from my staging environment and I verified the container is no longer present in the entity-operator pod. I tried deleting one of the KafkaTopics and it seems to be hanging. I don't see anything in the events or in the operator logs. I'm not siure what's going on there.

kubectl delete kt strimzi.cruisecontrol.metrics --context staging -n strimzi-kafka-cluster
kafkatopic.kafka.strimzi.io "strimzi.cruisecontrol.metrics" deleted
(hanging)

[scholzj]

Hmm, you are right ... the topics still have the finalizers. I guess you can try a command like this to remove them first:

kubectl get kt -o=json | jq '.items[].metadata.finalizers = null' | kubectl apply -f -

Other options might be to do it manually topic by topic with kubect edit. Or you can reenable the Topic Operator and:

• Either unmanage the topics and delete them: https://strimzi.io/docs/operators/latest/full/deploying.html#proc-converting-managed-topics-str
• or disable the finalizers: https://strimzi.io/docs/operators/latest/full/deploying.html#deploying-the-topic-operator-standalone-str

[jslusher]

The second option, which is what I was leaning toward, isn't going to work because my topicOperator isn't standalone. I don't see an option to set env in kafka.spec.entityOperator.topicOperator. Am I correct about that? If so I'll go with the first option I think. I've heard that editing finalizers directly out of objects can cause issues.

[scholzj]

You can use the https://strimzi.io/docs/operators/latest/full/configuring.html#type-ContainerTemplate-reference to specify the ENV var for the TO container. It will be under .spec.entityOperator.template.topicOperatorContainer or something like that.