don't rollout VMSS model updates when tags change

Author: nojnhuh

azure/const.go

@@ -23,6 +23,12 @@ const (
 	// for annotation formatting rules.
 	VMTagsLastAppliedAnnotation = "sigs.k8s.io/cluster-api-provider-azure-last-applied-tags-vm"
 
+	// VMSSTagsLastAppliedAnnotation is the key for the machine object annotation
+	// which tracks the AdditionalTags in the MachinePool Provider Config.
+	// See https://kubernetes.io/docs/concepts/overview/working-with-objects/annotations/
+	// for annotation formatting rules.
+	VMSSTagsLastAppliedAnnotation = "sigs.k8s.io/cluster-api-provider-azure-last-applied-tags-vmss"
+
 	// RGTagsLastAppliedAnnotation is the key for the Azure Cluster object annotation
 	// which tracks the AdditionalTags for Resource Group which is part in the Azure Cluster.
 	// See https://kubernetes.io/docs/concepts/overview/working-with-objects/annotations/

azure/defaults.go

@@ -217,6 +217,11 @@ func VMID(subscriptionID, resourceGroup, vmName string) string {
 	return fmt.Sprintf("/subscriptions/%s/resourceGroups/%s/providers/Microsoft.Compute/virtualMachines/%s", subscriptionID, resourceGroup, vmName)
 }
 
+// VMSSID returns the azure resource ID for a given VMSS.
+func VMSSID(subscriptionID, resourceGroup, vmssName string) string {
+	return fmt.Sprintf("/subscriptions/%s/resourceGroups/%s/providers/Microsoft.Compute/virtualMachineScaleSets/%s", subscriptionID, resourceGroup, vmssName)
+}
+
 // VNetID returns the azure resource ID for a given VNet.
 func VNetID(subscriptionID, resourceGroup, vnetName string) string {
 	return fmt.Sprintf("/subscriptions/%s/resourceGroups/%s/providers/Microsoft.Network/virtualNetworks/%s", subscriptionID, resourceGroup, vnetName)

azure/scope/machinepool.go

@@ -20,6 +20,7 @@ import (
 	"context"
 	"crypto/sha256"
 	"encoding/base64"
+	"encoding/json"
 	"fmt"
 	"io"
 	"strings"
@@ -946,3 +947,41 @@ func (m *MachinePoolScope) ReconcileReplicas(ctx context.Context, vmss *azure.VM
 
 	return nil
 }
+
+// AnnotationJSON returns a map[string]interface from a JSON annotation.
+func (m *MachinePoolScope) AnnotationJSON(annotation string) (map[string]interface{}, error) {
+	out := map[string]interface{}{}
+	jsonAnnotation := m.AzureMachinePool.GetAnnotations()[annotation]
+	if jsonAnnotation == "" {
+		return out, nil
+	}
+	err := json.Unmarshal([]byte(jsonAnnotation), &out)
+	if err != nil {
+		return out, err
+	}
+	return out, nil
+}
+
+// UpdateAnnotationJSON updates the `annotation` with
+// `content`. `content` in this case should be a `map[string]interface{}`
+// suitable for turning into JSON. This `content` map will be marshalled into a
+// JSON string before being set as the given `annotation`.
+func (m *MachinePoolScope) UpdateAnnotationJSON(annotation string, content map[string]interface{}) error {
+	b, err := json.Marshal(content)
+	if err != nil {
+		return err
+	}
+	m.SetAnnotation(annotation, string(b))
+	return nil
+}
+
+// TagsSpecs returns the tags for the AzureMachinePool.
+func (m *MachinePoolScope) TagsSpecs() []azure.TagsSpec {
+	return []azure.TagsSpec{
+		{
+			Scope:      azure.VMSSID(m.SubscriptionID(), m.NodeResourceGroup(), m.Name()),
+			Tags:       m.AdditionalTags(),
+			Annotation: azure.VMSSTagsLastAppliedAnnotation,
+		},
+	}
+}

azure/types.go

@@ -126,7 +126,6 @@ func (vmss VMSS) HasModelChanges(other VMSS) bool {
 	equal := cmp.Equal(vmss.Image, other.Image) &&
 		cmp.Equal(vmss.Identity, other.Identity) &&
 		cmp.Equal(vmss.Zones, other.Zones) &&
-		cmp.Equal(vmss.Tags, other.Tags) &&
 		cmp.Equal(vmss.Sku, other.Sku)
 	return !equal
 }

azure/types_test.go

@@ -124,18 +124,6 @@ func TestVMSS_HasModelChanges(t *testing.T) {
 			},
 			HasModelChanges: true,
 		},
-		{
-			Name: "with different Tags",
-			Factory: func() (VMSS, VMSS) {
-				l := getDefaultVMSSForModelTesting()
-				l.Tags = infrav1.Tags{
-					"bin": "baz",
-				}
-				r := getDefaultVMSSForModelTesting()
-				return r, l
-			},
-			HasModelChanges: true,
-		},
 	}
 
 	for _, c := range cases {

exp/controllers/azuremachinepool_reconciler.go

@@ -25,6 +25,7 @@ import (
 	"sigs.k8s.io/cluster-api-provider-azure/azure/services/resourceskus"
 	"sigs.k8s.io/cluster-api-provider-azure/azure/services/roleassignments"
 	"sigs.k8s.io/cluster-api-provider-azure/azure/services/scalesets"
+	"sigs.k8s.io/cluster-api-provider-azure/azure/services/tags"
 	"sigs.k8s.io/cluster-api-provider-azure/util/tele"
 )
 
@@ -49,12 +50,17 @@ func newAzureMachinePoolService(machinePoolScope *scope.MachinePoolScope) (*azur
 	if err != nil {
 		return nil, errors.Wrap(err, "failed to create a scalesets service")
 	}
+	tagsSvc, err := tags.New(machinePoolScope)
+	if err != nil {
+		return nil, errors.Wrap(err, "failed creating tags service")
+	}
 
 	return &azureMachinePoolService{
 		scope: machinePoolScope,
 		services: []azure.ServiceReconciler{
 			scaleSetsSvc,
 			roleAssignmentsSvc,
+			tagsSvc,
 		},
 		skuCache: cache,
 	}, nil