After enabling the IPv6DualStack feature gate on the the kube-apiserver, services cannot be created as normal. This blocks the Monitoring operator in particular. We added the ability to strip feature gates to avoid reverting the api change.
This is POST until we merge the KAS-O bump;
Ke Wang, this is easy to verify, just check: under KAS pod's kube-apiserver process's configuration file, the field apiServerArguments.feature-gates does not include the one in bug title, and / or check KAS pod logs about feature gates exclude the one in bug title. More knowledge about feature gates for you: from the PR's file config/v1/types_feature.go, feature gate sets include Default, CustomNoUpgrade, TechPreviewNoUpgrade and LatencySensitive. Each one defines what feature gates is Enabled and Disabled. "Default" is used when `oc get FeatureGate cluster -o yaml` spec.featureSet is empty. CustomNoUpgrade or TechPreviewNoUpgrade is used like bug 1731228#c17. For the one in bug title, per PR comment, it would not be supported currently Thx
Verified with OCP build as below, $ oc version Client Version: v4.4.0 Server Version: 4.4.0-0.nightly-2020-02-24-020331 Kubernetes Version: v1.17.1 - Steps, Selected on KAS pod and check the configuration file, check the default apiServerArguments of feature-gates, $ kubeapiserver_pod=$(oc get pod -n openshift-kube-apiserver | grep kube-apiserver | head -1 | awk '{print $1}') $ oc rsh -n openshift-kube-apiserver $kubeapiserver_pod sh-4.2# cat /etc/kubernetes/static-pod-resources/configmaps/config/config.yaml| python -m json.tool ... "feature-gates": [ "RotateKubeletServerCertificate=true", "SupportPodPidsLimit=true", "NodeDisruptionExclusion=true", "ServiceNodeExclusion=true", "SCTPSupport=true", "LegacyNodeRoleBehavior=false" ], ... We can see the IPv6DualStack feature gate was removed.
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHBA-2020:0581