support SMP in appropriate types

[sascha-tanke-bdr]

Some type definitions are not supporting strategic merge patches (SMP). This makes it hard, to patch resources from different sides.

An example:

An ArgoCD rolles out a patch to .spec.servers in dnses.operator.openshift.io, as it defines some forwards for special dns setups. On top Submariner Operator wants to patch its lighthouse forward into the same resource. That isn't working, as SMP is not support via a mergeKey (https://kubernetes.io/docs/tasks/manage-kubernetes-objects/declarative-config/#merge-individual-elements-of-a-list-of-complex-elements, https://github.com/kubernetes/apimachinery/blob/268a6d0fb19c92c9665e8f5cd85b564557038dc1/pkg/util/strategicpatch/patch.go#L321). This could be made possible by adding patchMergeKey to:

api/operator/v1/types_dns.go

Line 55 in bfcb56b

Servers []Server `json:"servers,omitempty"`

Would be nice to add this to all appropriate types.

[JoelSpeed]

Strategic merge patch is only for API types that are served by Kube directly, or for aggregated API servers. They are not for custom resources definitions (see slack)

So this type shouldn't have merge patch markers.

What it should have though is +listType=map and then +listMapKey.

However, this is a breaking change. If the list is otherwise not labelled, it is considered atomic, and so behaviour will change if we were to retrofit these tags now.