ADR on Product image selection

[Maleware]

ADR23 on design of operators to accept custom images

[fhennig]

Thanks for doing this Maxi!

I added some notes. Also it looks like the file doesn't have the .adoc extension (which also causes it to not be rendered by github)

[fhennig]

I want to link this ticket: stackabletech/issues#141 as it is relevant

[sbernauer]

Waiting for approval in Arch meeting

[maltesander]

I did a quick test with an untagged enum https://github.com/stackabletech/operator-rs/blob/image_version_crd/src/commons/image.rs (dont mind the names, i did not use the ADR names yet).
This leads to problems. First of the Custom and Auto variants get confused when deserializing, which causes the tests to fail. Secondly i cannot apply a CRD using this as all:

[customresourcedefinition.apiextensions.k8s.io/zookeeperznodes.zookeeper.stackable.tech](http://customresourcedefinition.apiextensions.k8s.io/zookeeperznodes.zookeeper.stackable.tech) created
The CustomResourceDefinition "zookeeperclusters.zookeeper.stackable.tech" is invalid:
* spec.validation.openAPIV3Schema.properties[spec].properties[version].anyOf[0].properties[productVersion].type: Forbidden: must be empty to be structural
* spec.validation.openAPIV3Schema.properties[spec].properties[version].anyOf[0].properties[repo].default: Forbidden: must be undefined to be structural
* spec.validation.openAPIV3Schema.properties[spec].properties[version].anyOf[0].properties[repo].type: Forbidden: must be empty to be structural
* spec.validation.openAPIV3Schema.properties[spec].properties[version].anyOf[0].properties[stackableVersion].type: Forbidden: must be empty to be structural
* spec.validation.openAPIV3Schema.properties[spec].properties[version].anyOf[0].type: Forbidden: must be empty to be structural
* spec.validation.openAPIV3Schema.properties[spec].properties[version].anyOf[1].properties[custom].type: Forbidden: must be empty to be structural
* spec.validation.openAPIV3Schema.properties[spec].properties[version].anyOf[1].properties[productVersion].type: Forbidden: must be empty to be structural
* spec.validation.openAPIV3Schema.properties[spec].properties[version].anyOf[1].type: Forbidden: must be empty to be structural
* spec.validation.openAPIV3Schema.properties[spec].properties[version].type: Required value: must not be empty for specified object fields

@teozkr said this could probably be fixed in kube-rs. But until then, our proposed solution does not work unless we actually use the enum variant names in the CRD (not using untagged), which will be another breaking change when trying to move back to the untagged version.

[sbernauer]

Thanks @maltesander!
I feared the same thing, so we have to use a complex enum I'd say

[sbernauer]

We also want a new attribute called pullSecrets similar to imagePullSecrets in spark-k8s setting https://kubernetes.io/docs/tasks/configure-pod-container/pull-image-private-registry/#create-a-pod-that-uses-your-secret

  pullPolicy: IfNotPresent # Enum. defaults to IfNotPresent
  pullSecrets:
    - name: regcred # reference to secret in same namespace

[sbernauer]

LGTM % commets.
Can you please rename the file to something like ADR023-product-image-selection.adoc (don't forget to update in current_adrs.adoc)

[Maleware]

@sbernauer done

[Maleware]

bors merge

[bors]

Configuration problem:
bors.toml: not found