Allow existing but empty resource names

[fassmus]

Hi,

This PR fixes #627. The validation now checks if metadata.name is available but allows empty string.

Best regards,
Florian

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[Liujingfang1]

please rebase

[Liujingfang1]

@fassmus Can you also take a look at #641, #596? I feel they are all related to the same problem.

[monopole]

#627 is a feature request, not a bug, and it's not clear that it's a desirable feature.

Names are an important part of the k8s api, and kustomize has an informal notion that all bases should "work" if applied to a cluster, so allowing empty base names just to allow the namePrefix field in an overlay to fully specify a name seems too clever and contrary to the notion of a functional base.

FWIW, #596 is fixed and unrelated to this.

#641 is related, in that the name field is expected to be empty - but only if there's a generateName directive. That's a different situation, and it's true that kustomize doesn't handle this at time of writing.

[fassmus]

I agree, using prefix for overwriting names is a bit of a hack. We decided to simply user generic names in the base layer with prefix in the overlay. Now objects created from different overlays all have the same "postfix" (name from the base) but this is not really an issue. Only for Service objects where the name is relevant at runtime of the application (DNS), we use a JSON patch in the overlay for setting the name to some desired value.

Therefore, I will retract the PR.