WIP: OKD-259: Validate OKD featureset to prevent it from being enabled on OCP clusters

build/root/Makefile

@@ -39,6 +39,8 @@ PRINT_HELP ?=
 WHAT ?=
 TESTS ?=
 BRANCH ?=
+TAGS ?=
+GO_BUILD_FLAGS := $(if ${TAGS},-tags=${TAGS},)
 
 # We don't need make's built-in rules.
 MAKEFLAGS += --no-builtin-rules
@@ -61,6 +63,11 @@ $(error Both KUBE_GOFLAGS and GOFLAGS are set. Please use just GOFLAGS)
 endif
 endif
 
+# Add build tags to GOFLAGS
+ifneq ($(TAGS),)
+GOFLAGS := $(GOFLAGS) $(GO_BUILD_FLAGS)
+endif
+
 # This controls the verbosity of the build.  Higher numbers mean more output.
 KUBE_VERBOSE ?= 1
 

openshift-hack/images/hyperkube/Dockerfile.rhel

@@ -1,14 +1,15 @@
 FROM registry.ci.openshift.org/ocp/builder:rhel-9-golang-1.24-openshift-4.20 AS builder
+ARG TAGS=""
 WORKDIR /go/src/k8s.io/kubernetes
 COPY . .
-RUN make WHAT='cmd/kube-apiserver cmd/kube-controller-manager cmd/kube-scheduler cmd/kubelet cmd/watch-termination openshift-hack/cmd/k8s-tests-ext' && \
+RUN make TAGS="${TAGS}" WHAT='cmd/kube-apiserver cmd/kube-controller-manager cmd/kube-scheduler cmd/kubelet cmd/watch-termination openshift-hack/cmd/k8s-tests-ext' && \
     mkdir -p /tmp/build && \
     cp openshift-hack/images/hyperkube/hyperkube openshift-hack/images/hyperkube/kubensenter /tmp/build && \
     cp /go/src/k8s.io/kubernetes/_output/local/bin/linux/$(go env GOARCH)/{kube-apiserver,kube-controller-manager,kube-scheduler,kubelet,watch-termination,k8s-tests-ext} \
     /tmp/build && \
     gzip /tmp/build/k8s-tests-ext
 
-FROM registry.ci.openshift.org/ocp/4.20:base-rhel9
+FROM registry.ci.openshift.org/origin/scos-4.20:base-stream9
 RUN yum install -y --setopt=tsflags=nodocs --setopt=skip_missing_names_on_install=False iproute && yum clean all
 COPY --from=builder /tmp/build/* /usr/bin/
 LABEL io.k8s.display-name="OpenShift Kubernetes Server Commands" \

openshift-kube-apiserver/admission/customresourcevalidation/features/validate_features.go

@@ -13,6 +13,7 @@ import (
 
 	configv1 "github.com/openshift/api/config/v1"
 	"k8s.io/kubernetes/openshift-kube-apiserver/admission/customresourcevalidation"
+	"k8s.io/kubernetes/openshift-kube-apiserver/version"
 )
 
 const PluginName = "config.openshift.io/ValidateFeatureGate"
@@ -50,14 +51,23 @@ func toFeatureGateV1(uncastObj runtime.Object) (*configv1.FeatureGate, field.Err
 type featureGateV1 struct {
 }
 
+func validateOKDFeatureSet(spec configv1.FeatureGateSpec) field.ErrorList {
+	allErrs := field.ErrorList{}
+	if spec.FeatureSet == configv1.OKD && !version.IsSCOS() {
+		allErrs = append(allErrs, field.Forbidden(field.NewPath("spec.featureSet"), "OKD featureset is not supported on OpenShift clusters"))
+	}
+
+	return allErrs
+}
+
 func (featureGateV1) ValidateCreate(_ context.Context, uncastObj runtime.Object) field.ErrorList {
 	obj, allErrs := toFeatureGateV1(uncastObj)
 	if len(allErrs) > 0 {
 		return allErrs
 	}
 
 	allErrs = append(allErrs, validation.ValidateObjectMeta(&obj.ObjectMeta, false, customresourcevalidation.RequireNameCluster, field.NewPath("metadata"))...)
-
+	allErrs = append(allErrs, validateOKDFeatureSet(obj.Spec)...)
 	return allErrs
 }
 
@@ -72,6 +82,7 @@ func (featureGateV1) ValidateUpdate(_ context.Context, uncastObj runtime.Object,
 	}
 
 	allErrs = append(allErrs, validation.ValidateObjectMetaUpdate(&obj.ObjectMeta, &oldObj.ObjectMeta, field.NewPath("metadata"))...)
+	allErrs = append(allErrs, validateOKDFeatureSet(obj.Spec)...)
 
 	return allErrs
 }

openshift-kube-apiserver/version/scos.go

@@ -0,0 +1,7 @@
+//go:build scos
+
+package version
+
+func init() {
+	SCOS = true
+}

openshift-kube-apiserver/version/version.go

@@ -0,0 +1,11 @@
+package version
+
+var (
+	// SCOS is a setting to enable CentOS Stream CoreOS-only modifications
+	SCOS = false
+)
+
+// IsSCOS returns true if CentOS Stream CoreOS-only modifications are enabled
+func IsSCOS() bool {
+	return SCOS
+}