Merge pull request kubernetes#3437 from DataDog/unexpected-vmssvms-cache-invalidations

Avoid unwanted VMSS VMs caches invalidations

Author: k8s-ci-robot

cluster-autoscaler/cloudprovider/azure/azure_cache.go

@@ -17,7 +17,6 @@ limitations under the License.
 package azure
 
 import (
-	"reflect"
 	"regexp"
 	"strings"
 	"sync"
@@ -62,7 +61,9 @@ func (m *asgCache) Register(asg cloudprovider.NodeGroup) bool {
 
 	for i := range m.registeredAsgs {
 		if existing := m.registeredAsgs[i]; strings.EqualFold(existing.Id(), asg.Id()) {
-			if reflect.DeepEqual(existing, asg) {
+			e := existing.(*ScaleSet)
+			a := asg.(*ScaleSet)
+			if e.minSize == a.minSize && e.maxSize == a.maxSize && e.curSize == a.curSize {
 				return false
 			}
 
@@ -181,7 +182,7 @@ func (m *asgCache) regenerate() error {
 
 	m.instanceToAsg = newCache
 
-	// Incalidating unowned instance cache.
+	// Invalidating unowned instance cache.
 	m.invalidateUnownedInstanceCache()
 
 	return nil

cluster-autoscaler/cloudprovider/azure/azure_manager.go

@@ -513,7 +513,7 @@ func (m *AzureManager) buildAsgFromSpec(spec string) (cloudprovider.NodeGroup, e
 	case vmTypeStandard:
 		return NewAgentPool(s, m)
 	case vmTypeVMSS:
-		return NewScaleSet(s, m)
+		return NewScaleSet(s, m, -1)
 	case vmTypeAKS:
 		return NewAKSAgentPool(s, m)
 	default:
@@ -700,7 +700,12 @@ func (m *AzureManager) listScaleSets(filter []labelAutoDiscoveryConfig) ([]cloud
 			continue
 		}
 
-		asg, err := NewScaleSet(spec, m)
+		curSize := int64(-1)
+		if scaleSet.Sku != nil && scaleSet.Sku.Capacity != nil {
+			curSize = *scaleSet.Sku.Capacity
+		}
+
+		asg, err := NewScaleSet(spec, m, curSize)
 		if err != nil {
 			klog.Warningf("ignoring nodegroup %q %s", *scaleSet.Name, err)
 			continue

cluster-autoscaler/cloudprovider/azure/azure_manager_test.go

@@ -751,7 +751,7 @@ func TestListScalesets(t *testing.T) {
 				minSize:           5,
 				maxSize:           50,
 				manager:           manager,
-				curSize:           -1,
+				curSize:           3,
 				sizeRefreshPeriod: defaultVmssSizeRefreshPeriod,
 			}},
 		},
@@ -857,7 +857,7 @@ func TestGetFilteredAutoscalingGroupsVmss(t *testing.T) {
 		minSize:           minVal,
 		maxSize:           maxVal,
 		manager:           manager,
-		curSize:           -1,
+		curSize:           3,
 		sizeRefreshPeriod: defaultVmssSizeRefreshPeriod,
 	}}
 	assert.True(t, assert.ObjectsAreEqualValues(expectedAsgs, asgs), "expected %#v, but found: %#v", expectedAsgs, asgs)

cluster-autoscaler/cloudprovider/azure/azure_scale_set.go

@@ -89,15 +89,15 @@ type ScaleSet struct {
 }
 
 // NewScaleSet creates a new NewScaleSet.
-func NewScaleSet(spec *dynamic.NodeGroupSpec, az *AzureManager) (*ScaleSet, error) {
+func NewScaleSet(spec *dynamic.NodeGroupSpec, az *AzureManager, curSize int64) (*ScaleSet, error) {
 	scaleSet := &ScaleSet{
 		azureRef: azureRef{
 			Name: spec.Name,
 		},
 		minSize: spec.MinSize,
 		maxSize: spec.MaxSize,
 		manager: az,
-		curSize: -1,
+		curSize: curSize,
 	}
 
 	if az.config.VmssCacheTTL != 0 {