add ability to detect vsphere csi migration

pkg/cloudprovider/external.go

@@ -22,6 +22,11 @@ func IsCloudProviderExternal(platformStatus *configv1.PlatformStatus, featureGat
 		return false, fmt.Errorf("platformStatus is required")
 	}
 	switch platformStatus.Type {
+	case configv1.VSpherePlatformType:
+		// vSphere has a special condition whereby CCM reversion must be possible in 4.13 OpenShift if the in-tree storage driver is enabled
+		disabled, err := isCSIMigrationvSphereDisabled(featureGate)
+		// we only want to use the in-tree cloud-provider when the migration is also disabled
+		return !disabled, err
 	case configv1.GCPPlatformType:
 		// Platforms that are external based on feature gate presence
 		return isExternalFeatureGateEnabled(featureGate)
@@ -32,8 +37,7 @@ func IsCloudProviderExternal(platformStatus *configv1.PlatformStatus, featureGat
 		configv1.KubevirtPlatformType,
 		configv1.NutanixPlatformType,
 		configv1.OpenStackPlatformType,
-		configv1.PowerVSPlatformType,
-		configv1.VSpherePlatformType:
+		configv1.PowerVSPlatformType:
 		return true, nil
 	default:
 		// Platforms that do not have external cloud providers implemented
@@ -48,18 +52,53 @@ func isExternalFeatureGateEnabled(featureGate *configv1.FeatureGate) (bool, erro
 		// If no featureGate is present, then the user hasn't opted in to the external cloud controllers
 		return false, nil
 	}
+
+	enabledFeatureGates, disabledFeatureGates, err := getEnabledDisabledFeatureGates(featureGate)
+	if err != nil {
+		return false, err
+	}
+
+	return !disabledFeatureGates.Has(ExternalCloudProviderFeature) && enabledFeatureGates.Has(ExternalCloudProviderFeature), nil
+}
+
+// isCSIMigrationvSphereDisabled determines whether the CSIMigrationvSphere feature gate is disabled in the current
+// feature set. This function only returns true when the feature is actively disabled, otherwise we should
+// deploy the CCM for vSphere.
+// This function is needed to help address a reversion issue that is happening in 1.26 Kubernetes,
+// which is also being brought to 4.13 OpenShift. This feature gate had been locked for 1.26, but has been
+// unlocked in https://github.com/kubernetes/kubernetes/pull/116342. This feature gate had been removed from OpenShift
+// as all vSphere clusters will be migrated to the CSI driver, due to the reversion we must support a situation where
+// a user has upgraded to 4.13 but must revert their storage driver to in-tree. This reversion will also require the
+// CCM to be migrated back to the in-tree KCM. Related storage JIRA, https://issues.redhat.com/browse/STOR-1265
+// TODO remove this function once it is no longer needed, presumably 4.14 OpenShift.
+func isCSIMigrationvSphereDisabled(featureGate *configv1.FeatureGate) (bool, error) {
+	if featureGate == nil {
+		// If no featureGate is present, then the user hasn't opted in to the in-tree vSphere driver
+		return false, nil
+	}
+
+	enabledFeatureGates, disabledFeatureGates, err := getEnabledDisabledFeatureGates(featureGate)
+	if err != nil {
+		return false, err
+	}
+
+	return !disabledFeatureGates.Has(configv1.InTreeVSphereVolumes) && enabledFeatureGates.Has(configv1.InTreeVSphereVolumes), nil
+}
+
+// get the enabled and disabled feature gates for the associated feature set
+func getEnabledDisabledFeatureGates(featureGate *configv1.FeatureGate) (sets.String, sets.String, error) {
 	featureSet, ok := configv1.FeatureSets[featureGate.Spec.FeatureSet]
 	if !ok {
-		return false, fmt.Errorf(".spec.featureSet %q not found", featureGate.Spec.FeatureSet)
+		return nil, nil, fmt.Errorf(".spec.featureSet %q not found", featureGate.Spec.FeatureSet)
 	}
 
-	enabledFeatureGates := sets.NewString(featureSet.Enabled...)
-	disabledFeatureGates := sets.NewString(featureSet.Disabled...)
-	// CustomNoUpgrade will override the deafult enabled feature gates.
+	enabled := sets.NewString(featureSet.Enabled...)
+	disabled := sets.NewString(featureSet.Disabled...)
+	// CustomNoUpgrade will override the default enabled feature gates.
 	if featureGate.Spec.FeatureSet == configv1.CustomNoUpgrade && featureGate.Spec.CustomNoUpgrade != nil {
-		enabledFeatureGates = sets.NewString(featureGate.Spec.CustomNoUpgrade.Enabled...)
-		disabledFeatureGates = sets.NewString(featureGate.Spec.CustomNoUpgrade.Disabled...)
+		enabled = sets.NewString(featureGate.Spec.CustomNoUpgrade.Enabled...)
+		disabled = sets.NewString(featureGate.Spec.CustomNoUpgrade.Disabled...)
 	}
 
-	return !disabledFeatureGates.Has(ExternalCloudProviderFeature) && enabledFeatureGates.Has(ExternalCloudProviderFeature), nil
+	return enabled, disabled, nil
 }