[Bug]: kubeconform validation fails for kafka crd

[abrarshivani]

Bug Description

When configuring a Kafka listener with the type set to cluster-ip, overrides for the bootstrap service may not be necessary, but they may still be required for brokers. This results in the following listener configuration:

      - name: external
        port: 9095
        type: cluster-ip
        tls: true
        authentication:
          type: tls
        configuration:
          bootstrap: {}
          brokers:
          - broker: 0
            host: broker-0.domain.com
          - broker: 1
            host: broker-1.domain.com
          - broker: 2
            host: broker-2.domain.com

When validating this CRD with kubeconform, an error is encountered: kubeconform expected object, but got null. Additionally, the CRD needs to be adjusted since the bootstrap value can indeed be null. This issue can be resolved by adding the following property for the bootstrap configuration in the Kafka CRD:

                              bootstrap:
                                anyOf:
                                - type: "null"
                                - type: object

Steps to reproduce

1. Use script https://github.com/yannh/kubeconform/blob/master/scripts/openapi2jsonschema.py to generate schema:
   python3 openapi2jsonschema.py <path_to_openapi_crd>.yaml
2. Use kubeconform to validate crd against the schema generated:
   kubeconform -kubernetes-version 1.22.0 -strict -schema-location <dir_to_openapi_crd>/{{.ResourceKind}}{{.KindSuffix}}.json '<path-to-crd>

Expected behavior

Kubeconform should not return error: expected object, but got null

Strimzi version

0.34.0

Kubernetes version

v1.24.17

Installation method

Helm Chart

Infrastructure

EKS

Configuration files and logs

No response

Additional context

No response

[scholzj]

I do not think we are aware of any issues with the CRDs. This functionality is regularly used and tested. So I'm not sure what exactly is supposed to be a bug. Also, we are not going to fix any CRDs for a Strimzi 0.34.0 release which is quite old.

[abrarshivani]

The issue is not related to deployment of kafka, the deployment using the CRD is working as expected. However, the validation framework kubeconform (https://github.com/yannh/kubeconform) fails to validate as from kafka crd definition it looks like bootstrap should be of object type but it can be null as well.
I think if we could have indication in crd that bootstrap configuration for the listener could be null it would help the validation frameworks.

[scholzj]

I still don't really understand what are you asking for. The bootstrap configuration is not required. So yes, it could be null / missing.