Round 2: Kafka Channel Controller

[evankanderson]

Write a controller for Kafka Channels and Provisioners. This should:

1. Create the Provisioner/update the Status
2. Define required fields (if any) in Channel arguments.
3. Allocate Kafka Topics (and Subscriptions?) as needed.
4. Copy configuration from Channel CR to delivery implementation (Round 2: Kafka Channel Delivery #441 )
5. Update Status based on the success of 3
6. Test coverage > 80%
7. Deployment which runs the Channel controller
8. Minimal RBAC rules for 1,3,4

[evankanderson]

I expect this will probably be multiple PRs. We should aim to produce this incrementally with test coverage at each stage.

[neosab]

I gave the task 1. Create the Provisioner/update the Status a shot and I will post my WIP PR soon for that.

[neosab]

/assign neosab

[matzew]

3. Allocate Kafka Topics (and Subscriptions?) as needed.

@evankanderson would it make sense to create topics, based on a custom resources, like

apiVersion: kafka.strimzi.io/v1alpha1
kind: KafkaTopic
metadata:
  name: my-topic
  labels:
    strimzi.io/cluster: my-cluster
spec:
  partitions: 1
  replicas: 1
  config:
    retention.ms: 7200000
    segment.bytes: 1073741824

See for details https://github.com/strimzi/strimzi-kafka-operator/blob/master/examples/topic/kafka-topic.yaml

[evankanderson]

@scothis might have more opinions here. I'd be cautiously optimistic on being able to incorporate third-party utilities like this as part of the Kafka Channel implementation, but I'm going to defer to Scott who has more experience in this area as to how much this will help.

[neosab]

#468 now addresses most of the tasks but for the message delivery implementation and the k8s service fronting the channel.