fix: Updated instanceTypeZones logic to handle non-zonal SKUs in zona…

…l regions (#410)

pkg/providers/instancetype/instancetypes.go

@@ -145,12 +145,13 @@ func instanceTypeZones(sku *skewer.SKU, region string) sets.Set[string] {
 	// skewer returns numerical zones, like "1" (as keys in the map);
 	// prefix each zone with "<region>-", to have them match the labels placed on Node (e.g. "westus2-1")
 	// Note this data comes from LocationInfo, then skewer is used to get the SKU info
-	if hasZonalSupport(region) {
-		return sets.New(lo.Map(lo.Keys(sku.AvailabilityZones(region)), func(zone string, _ int) string {
+	// If an offering is non-zonal, the availability zones will be empty.
+	skuZones := lo.Keys(sku.AvailabilityZones(region))
+	if hasZonalSupport(region) && len(skuZones) > 0 {
+		return sets.New(lo.Map(skuZones, func(zone string, _ int) string {
 			return fmt.Sprintf("%s-%s", region, zone)
 		})...)
 	}
-
 	return sets.New("") // empty string means non-zonal offering
 }
 

pkg/providers/instancetype/suite_test.go

@@ -343,7 +343,6 @@ var _ = Describe("InstanceType Provider", func() {
 		It("should not include confidential SKUs", func() {
 			Expect(instanceTypes).ShouldNot(ContainElement(WithTransform(getName, Equal("Standard_DC8s_v3"))))
 		})
-
 	})
 	Context("Filtering GPU SKUs ProviderList(AzureLinux)", func() {
 		var instanceTypes corecloudprovider.InstanceTypes
@@ -1186,6 +1185,25 @@ var _ = Describe("InstanceType Provider", func() {
 			vm := azureEnvNonZonal.VirtualMachinesAPI.VirtualMachineCreateOrUpdateBehavior.CalledWithInput.Pop().VM
 			Expect(vm.Zones).To(BeEmpty())
 		})
+		It("should support provisioning non-zonal instance types in zonal regions", func() {
+			coretest.ReplaceRequirements(nodePool, corev1beta1.NodeSelectorRequirementWithMinValues{
+				NodeSelectorRequirement: v1.NodeSelectorRequirement{
+					Key:      v1.LabelInstanceTypeStable,
+					Operator: v1.NodeSelectorOpIn,
+					Values:   []string{"Standard_NC6s_v3"},
+				}})
+			ExpectApplied(ctx, env.Client, nodePool, nodeClass)
+
+			pod := coretest.UnschedulablePod()
+			ExpectProvisioned(ctx, env.Client, cluster, cloudProvider, coreProvisioner, pod)
+
+			node := ExpectScheduled(ctx, env.Client, pod)
+			Expect(node.Labels).To(HaveKeyWithValue(v1alpha2.AlternativeLabelTopologyZone, ""))
+
+			Expect(azureEnv.VirtualMachinesAPI.VirtualMachineCreateOrUpdateBehavior.CalledWithInput.Len()).To(Equal(1))
+			vm := azureEnv.VirtualMachinesAPI.VirtualMachineCreateOrUpdateBehavior.CalledWithInput.Pop().VM
+			Expect(vm.Zones).To(BeEmpty())
+		})
 	})
 })