Kustomization - Add support for buildMetadata

[moshloop]

We use the originAnnotations buildMetadata flag to track where resources originate and the only way to include them currently is by updating the kustomization.yaml file directly and not through the CRD

[matheuscscp]

Interesting feature! @moshloop are you willing to contribute this feature?

[stefanprodan]

originAnnotations does not work with Flux, we offer source tracking via flux trace.

[matheuscscp]

Looks like buildMetadata can embed other information beyond source revision that is relevant for debugging a complex kustomize build, e.g. which transformers touched your resources: https://kubectl.docs.kubernetes.io/references/kustomize/kustomization/buildmetadata/

[moshloop]

@matheuscscp Yes, happy to contribute just wanted to create an issue first to iron out any design issues

@stefanprodan Our use case is enabling users to "edit" a live kubernetes resource by submitting a Pull Request to the source. flux trace is great but it doesn't actually provide the path to the file, only to the kustomization.yaml. Our approach (which is completely outside the scope for core flux) is to use the originAnnotations and mirror what trace does, but using our configuration db which doesn't require access to the api server and can work across clusters for Kustomization objects that use a target kubeconfig

This works great, but it requires updating the kustomization.yaml directly rather than asking the Kustomization CRD to merge into it before building.

[matheuscscp]

@moshloop Are you using Flux to power that product? I don't see any mention of Flux in the home page

[moshloop]

@matheuscscp Our product stays completely out of the provisioning / reconciliation loop - we scrape Kubernetes clusters into a CMDB, understand the Flux resources and relationships and then use it to commit changes back to git where the normal Flux reconciliation loop takes place.

But thanks for pointing out how that isn't clear, will definitely update our website

[stefanprodan]

buildMetadata with originAnnotations was implemented and will be released in Flux 2.9

ref: fluxcd/kustomize-controller#1632