CloudProvider is defined in the Cluster Spec.

CloudProvider can be set at the kubelet level, however
if the user overrides kubelet values, CloudProvider isn't always
set at this point, leading to an error.

pkg/apis/kops/validation/legacy.go

@@ -592,7 +592,7 @@ func ValidateCluster(c *kops.Cluster, strict bool) *field.Error {
 	}
 
 	if c.Spec.Networking != nil && c.Spec.Networking.AmazonVPC != nil &&
-		c.Spec.Kubelet != nil && (c.Spec.Kubelet.CloudProvider != "aws") {
+		(c.Spec.CloudProvider != "aws") {
 		return field.Invalid(fieldSpec.Child("Networking"), "amazon-vpc-routed-eni", "amazon-vpc-routed-eni networking is supported only in AWS")
 	}