kubernetes: Kubernetes HPA returning incorrect API version

What happened:

When applying a HPA autoscaling/v2beta1 manifest, kubernetes accepts the manifest and returns the autoscaling/v1 version when querying the manifest.

What you expected to happen: Manifest to maintain autoscaling/v2beta1 api version

How to reproduce it (as minimally and precisely as possible):

kubectl create -f hpa-demo.yaml

apiVersion: autoscaling/v2beta1
kind: HorizontalPodAutoscaler
metadata:
  name: hpa-demo
spec:
  scaleTargetRef:
    apiVersion: extensions/v1beta1
    kind: Deployment
    name: hpa-demo-master
  minReplicas: 1
  maxReplicas: 5
  metrics:
  - type: Resource
    resource:
      name: cpu
      targetAverageUtilization: 80
  - type: Resource
    resource:
      name: memory
      targetAverageUtilization: 80

kubectl get hpa -o yaml hpa-demo

apiVersion: autoscaling/v1
kind: HorizontalPodAutoscaler
metadata:
  annotations:
    autoscaling.alpha.kubernetes.io/conditions: '[{"type":"AbleToScale","status":"True","lastTransitionTime":"2018-11-29T10:53:31Z","reason":"ReadyForNewScale","message":"the
      last scale time was sufficiently old as to warrant a new scale"},{"type":"ScalingActive","status":"True","lastTransitionTime":"2018-11-29T10:53:31Z","reason":"ValidMetricFound","message":"the
      HPA was able to successfully calculate a replica count from memory resource
      utilization (percentage of request)"},{"type":"ScalingLimited","status":"False","lastTransitionTime":"2018-11-29T10:53:31Z","reason":"DesiredWithinRange","message":"the
      desired count is within the acceptable range"}]'
    autoscaling.alpha.kubernetes.io/current-metrics: '[{"type":"Resource","resource":{"name":"memory","currentAverageUtilization":38,"currentAverageValue":"4018176"}},{"type":"Resource","resource":{"name":"cpu","currentAverageUtilization":20,"currentAverageValue":"1m"}}]'
    autoscaling.alpha.kubernetes.io/metrics: '[{"type":"Resource","resource":{"name":"memory","targetAverageUtilization":80}}]'
    kubectl.kubernetes.io/last-applied-configuration: |
      {"apiVersion":"autoscaling/v2beta1","kind":"HorizontalPodAutoscaler","metadata":{"annotations":{},"name":"hpa-demo","namespace":"staging0"},"spec":{"maxReplicas":5,"metrics":[{"resource":{"name":"cpu","targetAverageUtilization":80},"type":"Resource"},{"resource":{"name":"memory","targetAverageUtilization":80},"type":"Resource"}],"minReplicas":1,"scaleTargetRef":{"apiVersion":"extensions/v1beta1","kind":"Deployment","name":"hpa-demo-master"}}}
  creationTimestamp: 2018-11-29T10:52:01Z
  name: hpa-demo
  namespace: staging0
  resourceVersion: "718045"
  selfLink: /apis/autoscaling/v1/namespaces/staging0/horizontalpodautoscalers/hpa-demo
  uid: cd513382-f3c4-11e8-9fa7-02bf9ef29fa4
spec:
  maxReplicas: 5
  minReplicas: 1
  scaleTargetRef:
    apiVersion: extensions/v1beta1
    kind: Deployment
    name: hpa-demo-master
  targetCPUUtilizationPercentage: 80
status:
  currentCPUUtilizationPercentage: 20
  currentReplicas: 1
  desiredReplicas: 1

As you can see from the above, the manifest is accepted by kubernetes on creation, when retrieving the mainfest it’s returned in v1 format.

If we explicitly define the apiversion, we get the correct response. kubectl get hpa.v2beta1.autoscaling -o yaml hpa-demo

apiVersion: autoscaling/v2beta1
kind: HorizontalPodAutoscaler
metadata:
  annotations:
    kubectl.kubernetes.io/last-applied-configuration: |
      {"apiVersion":"autoscaling/v2beta1","kind":"HorizontalPodAutoscaler","metadata":{"annotations":{},"name":"hpa-demo","namespace":"staging0"},"spec":{"maxReplicas":5,"metrics":[{"resource":{"name":"cpu","targetAverageUtilization":80},"type":"Resource"},{"resource":{"name":"memory","targetAverageUtilization":80},"type":"Resource"}],"minReplicas":1,"scaleTargetRef":{"apiVersion":"extensions/v1beta1","kind":"Deployment","name":"hpa-demo-master"}}}
  creationTimestamp: 2018-11-29T10:52:01Z
  name: hpa-demo
  namespace: staging0
  resourceVersion: "718045"
  selfLink: /apis/autoscaling/v2beta1/namespaces/staging0/horizontalpodautoscalers/hpa-demo
  uid: cd513382-f3c4-11e8-9fa7-02bf9ef29fa4
spec:
  maxReplicas: 5
  metrics:
  - resource:
      name: memory
      targetAverageUtilization: 80
    type: Resource
  - resource:
      name: cpu
      targetAverageUtilization: 80
    type: Resource
  minReplicas: 1
  scaleTargetRef:
    apiVersion: extensions/v1beta1
    kind: Deployment
    name: hpa-demo-master
status:
  conditions:
  - lastTransitionTime: 2018-11-29T10:53:31Z
    message: the last scale time was sufficiently old as to warrant a new scale
    reason: ReadyForNewScale
    status: "True"
    type: AbleToScale
  - lastTransitionTime: 2018-11-29T10:53:31Z
    message: the HPA was able to successfully calculate a replica count from memory
      resource utilization (percentage of request)
    reason: ValidMetricFound
    status: "True"
    type: ScalingActive
  - lastTransitionTime: 2018-11-29T10:53:31Z
    message: the desired count is within the acceptable range
    reason: DesiredWithinRange
    status: "False"
    type: ScalingLimited
  currentMetrics:
  - resource:
      currentAverageUtilization: 38
      currentAverageValue: "4018176"
      name: memory
    type: Resource
  - resource:
      currentAverageUtilization: 20
      currentAverageValue: 1m
      name: cpu
    type: Resource
  currentReplicas: 1
  desiredReplicas: 1

Anything else we need to know?:

Environment:

• Kubernetes version (use kubectl version):

Client Version: version.Info{Major:"1", Minor:"10", GitVersion:"v1.10.3", GitCommit:"2bba0127d85d5a46ab4b778548be28623b32d0b0", GitTreeState:"clean", BuildDate:"2018-05-21T09:17:39Z", GoVersion:"go1.9.3", Compiler:"gc", Platform:"darwin/amd64"}
Server Version: version.Info{Major:"1", Minor:"10", GitVersion:"v1.10.10", GitCommit:"be1a908c6aa47e0ae1b1dc861a1de6ccfe963aa2", GitTreeState:"clean", BuildDate:"2018-11-13T11:33:04Z", GoVersion:"go1.9.3", Compiler:"gc", Platform:"linux/amd64"}

• Cloud provider or hardware configuration: AWS
• OS (e.g. from /etc/os-release): Container Linux by CoreOS 1520.9.0 (Ladybug) 4.13.16-coreos-r1 docker://1.12.6
• Kernel (e.g. uname -a):a
• Install tools:
• Others:

/kind bug