Verify K8s 1.11 fixes our generation woes

[mattmoor]

We currently manipulate a Generation field ourselves in each of the Elafros resource (e.g.).

Check whether this landed in 1.10, and if so remove this logic.

1.10 is available to Alpha GKE clusters now: https://cloud.google.com/kubernetes-engine/release-notes

Since this involves updating the version of our K8s dependency, be sure to update the getting started documentation.

[mattmoor]

We've hit a few problems using 1.10 in GKE Alpha clusters, so my optimism that we'd resolve this in M4 is subsiding.

[dprotaso]

You can assign this to @bsnchan and I (@dprotaso) - we'll update our self hosted cluster to 1.10.1

This issue kubernetes/kubernetes#62595 highlights that enabling subresources fixes the generation woes

[mattmoor]

/assign @dprotaso @bsnchan

[bsnchan]

@mattmoor - Since this repo is not yet public, are we okay if this is a breaking change for CRD objects that do not use sub-resources?

[bsnchan]

It looks like enabling the feature gate flag to be CustomResourceSubresources=true (which is required for letting the api bump the generation) will break monitoring. The prometheus-operator pod will fail to create the CoreOS CRDs with the following error: https://gist.github.com/bsnchan/1f721c6e9f7aa989cb0c070ed305bd02

It's not obvious in the gist but the CRD validation schema is including an extra Required property
ie.

apiVersion: apiextensions.k8s.io/v1beta1
kind: CustomResourceDefinition
spec:
  ...
  validation:
   # openAPIV3Schema is the schema for validating custom objects.
    openAPIV3Schema:
      required: ["spec"] # this causes the break
      properties: ...

Generated here: https://github.com/coreos/prometheus-operator/blob/master/pkg/client/monitoring/v1/openapi_generated.go#L86

This fails validation in the API server here: https://github.com/kubernetes/apiextensions-apiserver/blob/master/pkg/apis/apiextensions/validation/validation.go#L211

/cc @mdemirhan

[dprotaso]

Blocked on prometheus-operator/prometheus-operator#1293 (if we want to keep the prometheus operator)