Kfserving: The InferenceService "sklearn-iris" is invalid: metadata.managedFields.fieldsType: Invalid value: "": must be `FieldsV1`

[kmr0877]

/kind bug

What steps did you take and what happened:
I am trying to test KFServing Installation, setting up for the first time from Test KFServing Installation .
Not really sure if its a bug?

Commands shown below

kubectl create namespace kfserving-test
kubectl apply -f docs/samples/sklearn/sklearn.yaml -n kfserving-test

Error message:

The InferenceService "sklearn-iris" is invalid: metadata.managedFields.fieldsType: Invalid value: "": must be `FieldsV1`

What did you expect to happen:

$ inferenceservice.serving.kubeflow.org/sklearn-iris created

Anything else you would like to add:

• I have got istio installed with manifest from Installing Istio without sidecar injection and Knative components using Operators
• Not sure if its an issue with any of the versions i am using?

$ kubectl get pods --namespace knative-serving
NAME                                READY   STATUS     RESTARTS   AGE
activator-6d9f95b7f8-k5gtd          2/2     Running    0          24m
autoscaler-597fd8d69d-b6htb         2/2     Running    0          24m
autoscaler-hpa-5878b57d96-fvrm7     2/2     Running    1          24m
controller-7479cc984d-m7dxh         2/2     Running    1          24m
istio-webhook-64b48869b8-nmckd      2/2     Running    1          24m
networking-istio-7bb58f6d55-2hlgw   1/1     Running    0          24m
storage-version-migration-bcq59     1/2     NotReady   2          24m
webhook-bf465f954-2nbq9             2/2     Running    1          24m

Environment:

• Istio Version:

$ istioctl version
client version: 1.6.4
control plane version: 1.6.4
data plane version: 1.6.4 (10 proxies)

• Knative Version:

v0.15.0

• KFServing Version:

$ kubectl get KnativeServing knative-serving -n knative-serving
NAME              VERSION   READY   REASON
knative-serving   0.15.0    True

• Kubeflow version:
  NA

• Kfdef:[k8s_istio/istio_dex/gcp_basic_auth/gcp_iap/aws/aws_cognito/ibm]
  NA

• Minikube version:

$ minikube  version
minikube version: v1.11.0
commit: 57e2f55f47effe9ce396cea42a1e0eb4f611ebbd

• Kubernetes version: (use kubectl version):
  `sh $ kubectl version Client Version: version.Info{Major:"1", Minor:"18", GitVersion:"v1.18.5", GitCommit:"e6503f8d8f769ace2f338794c914a96fc335df0f", GitTreeState:"clean", BuildDate:"2020-06-26T03:47:41Z", GoVersion:"go1.13.9", Compiler:"gc", Platform:"windows/amd64"} Server Version: version.Info{Major:"1", Minor:"18", GitVersion:"v1.18.3", GitCommit:"2e7996e3e2712684bc73f0dec0200d64eec7fe40", GitTreeState:"clean", BuildDate:"2020-05-20T12:43:34Z", GoVersion:"go1.13.9", Compiler:"gc", Platform:"linux/amd64"}
• OS (e.g. from /etc/os-release):
  ```sh
  Edition Windows 10 Enterprise
  Version 1903
  Installed on 24/01/2020
  OS build 18362.778

[issue-label-bot[bot]]

Issue-Label Bot is automatically applying the labels:

| Label | Probability |
| ------------- | ------------- |
| area/inference | 0.64 |

Please mark this comment with :thumbsup: or :thumbsdown: to give our bot feedback!
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[issue-label-bot[bot]]

Issue-Label Bot is automatically applying the labels:

| Label | Probability |
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[yuzisun]

@kmr0877 you are on kubernetes 1.18 and looks like this is the same issue as https://github.com/GoogleCloudPlatform/flink-on-k8s-operator/issues/210, if you downgrade to 1.17 that should work. We will need to upgrade k8s client dependency for KFServing controller.

[kmr0877]

@yuzisun Seems like on downgrade to 1.17 works fine for me. Thanks for your response.
Worth upgrading k8s client, probably better to keep the issue open until its upgraded else we might end up seeing duplication as you mentioned above.
Feel free to close the issue if you have a different opinion.

[yuzisun]

released in 0.4.1