Kustomize kyaml panic on duplicate keys

[jonaskello]

I got the kustomizations stuck in "reconciliation in progress". When I checked the logs of the kustomization controller:

{"level":"info","ts":"2021-01-18T07:10:57.568Z","logger":"controller.kustomization","msg":"Starting workers","reconciler group":"kustomize.toolkit.fluxcd.io","reconciler kind":"Kustomization","worker count":4}
2021/01/18 07:10:59 failed to decode ynode: yaml: unmarshal errors:
  line 21: mapping key "env" already defined at line 18

And sure enough there was a yaml file that had the env key twice. However it was a bit hard to find which yaml. I have a multi-tenant setup (not sure if that is relevant) and the env key was present twice on an app manifest.

I would be nice if flux would error out the kustomization on this instead of hanging on "reconciliation in progress" and present the error on the kustomization object it pertains to.

[stefanprodan]

We can't log the object or manifest that triggers this since kustomize kyaml errors don't contain any information.

Using a deployment that declares two env keys, this is what kustomize build outputs:

$ kustomize build --enable_kyaml=true
2021/01/18 13:21:50 failed to decode ynode: yaml: unmarshal errors:
  line 50: mapping key "env" already defined at line 47

Note that kyaml doesn't return an error, instead it panics and crashed the whole controller, that's why the reconciliation is stuck.

The only thing we can do is disable kyaml in kustomize-controller, see #241

[stefanprodan]

I opened kubernetes-sigs/kustomize#3480