[Bug] KubeRay CRDs cannot be installed with Kubernetes 1.16.0

[DmitriGekhtman]

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KubeRay Component

ray-operator

What happened + What you expected to happen

KubeRay's CRDs are not compatible with Kubernetes versions 1.16 or older due to an API change in Kubernetes 1.17 introducing the x-kubernetes-map-type https://github.com/kubernetes/kubernetes/blob/master/CHANGELOG/CHANGELOG-1.17.md#api-changes

While the README does offer some guidance on suggested kubernetes versions, it could be useful to establish actual compatibility boundaries and perhaps introduce workarounds for Kubernetes 1.16 in particular. (1.15 is outside the range we'd want to support, given that 1.16 was the GA release for CRDs)

Reproduction script

Try kubectl create -k kuberay/ray-operator/config/default with a Kubernetes version 1.16. The result is

error: error validating "kuberay/ray-operator/config/default": error validating data: ValidationError(CustomResourceDefinition.spec.versions[0].schema.openAPIV3Schema.properties.spec.properties.headGroupSpec.properties.template.properties.spec.properties.nodeSelector): unknown field "x-kubernetes-map-type" in io.k8s.apiextensions-apiserver.pkg.apis.apiextensions.v1.JSONSchemaProps; if you choose to ignore these errors, turn validation off with --validate=false

Anything else

No response

Are you willing to submit a PR?

• [ ] Yes I am willing to submit a PR!

[Jeffwan]

Delete the x-kubernetes-map-type should work. BTW, this is expected and 1.16 is retired for long time and we should ask user to bump the version.

[DmitriGekhtman]

Delete the x-kubernetes-map-type should work.

Will pass that on :)

should ask user to bump the version

The particular user had to use an old Kubernetes version apparently due to internal constraints at their company.

[kevin85421]

Close this issue because the KubeRay community does not support Kubernetes 1.16.0.