Upgrading to 2.2.0, started getting "kustomize build failed: kustomization.yaml is empty"

[joaocc]

Describe the bug

Since upgrading to 2.2.0 (or 2.2.2) from 2.1.x, we started receiving the following errors kustomize build failed: kustomization.yaml is empty
This is from a Kustomization object (kustomize.toolkit.fluxcd.io/v1) pointing to a folder with no resources.
Previously these were silently ignored, and kustomizations would suceed.

Steps to reproduce

---
apiVersion: kustomize.toolkit.fluxcd.io/v1
kind: Kustomization
metadata:
  name: level-1
  namespace: flux-system
spec:
  interval: 5m0s
  path: ./res/level-1
  dependsOn:
    - name: level-0
  prune: true
  sourceRef:
    kind: GitRepository
    name: my-own-git # this must match the name under which this repo has been created on the system

Expected behavior

The kustomization would process an empty folder and would suceed

Screenshots and recordings

No response

OS / Distro

Ubuntu

Flux version

v2.2.2

Flux check

flux check
► checking prerequisites
✔ Kubernetes 1.28.4-eks-8cb36c9 >=1.26.0-0
► checking version in cluster
✔ distribution: flux-2.2.2
✔ bootstrapped: false
► checking controllers
✔ helm-controller: deployment ready
► ghcr.io/fluxcd/helm-controller:v0.37.2
✔ image-automation-controller: deployment ready
► ghcr.io/fluxcd/image-automation-controller:v0.37.0
✔ image-reflector-controller: deployment ready
► ghcr.io/fluxcd/image-reflector-controller:v0.31.1
✔ kustomize-controller: deployment ready
► ghcr.io/fluxcd/kustomize-controller:v1.2.1
✔ notification-controller: deployment ready
► ghcr.io/fluxcd/notification-controller:v1.2.3
✔ source-controller: deployment ready
► ghcr.io/fluxcd/source-controller:v1.2.3
► checking crds
✔ alerts.notification.toolkit.fluxcd.io/v1beta3
✔ buckets.source.toolkit.fluxcd.io/v1beta2
✔ gitrepositories.source.toolkit.fluxcd.io/v1
✔ helmcharts.source.toolkit.fluxcd.io/v1beta2
✔ helmreleases.helm.toolkit.fluxcd.io/v2beta2
✔ helmrepositories.source.toolkit.fluxcd.io/v1beta2
✔ imagepolicies.image.toolkit.fluxcd.io/v1beta2
✔ imagerepositories.image.toolkit.fluxcd.io/v1beta2
✔ imageupdateautomations.image.toolkit.fluxcd.io/v1beta1
✔ kustomizations.kustomize.toolkit.fluxcd.io/v1
✔ ocirepositories.source.toolkit.fluxcd.io/v1beta2
✔ providers.notification.toolkit.fluxcd.io/v1beta3
✔ receivers.notification.toolkit.fluxcd.io/v1
✔ all checks passed

Git provider

N/A

Container Registry provider

N/A

Additional context

No response

Code of Conduct

• I agree to follow this project's Code of Conduct

[stefanprodan]

The workaround is to place in the dir a kustomization.yaml like so:

apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization
resources: []

This will be fixed next year.

[joaocc]

Thanks for the prompt response. In this case, as a temporary workaround, i need to write an "empty" placeholder kustomization.yaml? That being the case, thanks for the workaround, and will look forward for the fix. Thanks

[joaocc]

Hi.
I tried the workaround and I still got the same error. I was only able to solve the issue if, instead of resources: [] I create a dummy file and point the kustomization.yaml there.
Is this expected?
Thanks

[cep21]

@stefanprodan Does this qualify as a breaking change? Should it have had a version number increase? We were hit by a similar issue when upgrading flux.

[mrparkers]

Just chiming in that the resources: [] workaround worked for me.

[joawin]

Hi,
i have the same problem.
When creating the file kustomization.yaml in the empty gitrepo i still get the message

"kustomize build failed: kustomization.yaml is empty"

kustomization.yaml in empty git repo

apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization
resources: []

Kustomization File

apiVersion: kustomize.toolkit.fluxcd.io/v1
kind: Kustomization
metadata:
  name: tenant-repo
  namespace: namespace
spec:
  interval: 1m
  path: "./"
  prune: true
  sourceRef:
    kind: GitRepository
    name: nameofrepo
  timeout: 2m
  serviceAccountName: m2m-sa
  decryption:
    provider: sops
    secretRef:
      name: tenant-agekey

[stefanprodan]

This will be fixed in the next patch version, I have found a way to deal with the Kustomize break change.

Meanwhile @joawin you can set targetNamespace in your tenant Flux Kustomization as a workaround.