fix: Refresh VM cache when node is not found

(cherry picked from commit 8850c8c)

staging/src/k8s.io/legacy-cloud-providers/azure/azure.go

@@ -274,6 +274,8 @@ type Cloud struct {
 	ipv6DualStackEnabled bool
 	// Lock for access to node caches, includes nodeZones, nodeResourceGroups, and unmanagedNodes.
 	nodeCachesLock sync.RWMutex
+	// nodeNames holds current nodes for tracking added nodes in VM caches.
+	nodeNames sets.String
 	// nodeZones is a mapping from Zone to a sets.String of Node's names in the Zone
 	// it is updated by the nodeInformer
 	nodeZones map[string]sets.String
@@ -342,6 +344,7 @@ func NewCloudWithoutFeatureGates(configReader io.Reader) (*Cloud, error) {
 	}
 
 	az := &Cloud{
+		nodeNames:          sets.NewString(),
 		nodeZones:          map[string]sets.String{},
 		nodeResourceGroups: map[string]string{},
 		unmanagedNodes:     sets.NewString(),
@@ -782,6 +785,9 @@ func (az *Cloud) updateNodeCaches(prevNode, newNode *v1.Node) {
 	defer az.nodeCachesLock.Unlock()
 
 	if prevNode != nil {
+		// Remove from nodeNames cache.
+		az.nodeNames.Delete(prevNode.ObjectMeta.Name)
+
 		// Remove from nodeZones cache.
 		prevZone, ok := prevNode.ObjectMeta.Labels[LabelFailureDomainBetaZone]
 		if ok && az.isAvailabilityZone(prevZone) {
@@ -805,6 +811,9 @@ func (az *Cloud) updateNodeCaches(prevNode, newNode *v1.Node) {
 	}
 
 	if newNode != nil {
+		// Add to nodeNames cache.
+		az.nodeNames.Insert(newNode.ObjectMeta.Name)
+
 		// Add to nodeZones cache.
 		newZone, ok := newNode.ObjectMeta.Labels[LabelFailureDomainBetaZone]
 		if ok && az.isAvailabilityZone(newZone) {
@@ -876,6 +885,22 @@ func (az *Cloud) GetNodeResourceGroup(nodeName string) (string, error) {
 	return az.ResourceGroup, nil
 }
 
+// GetNodeNames returns a set of all node names in the k8s cluster.
+func (az *Cloud) GetNodeNames() (sets.String, error) {
+	// Kubelet won't set az.nodeInformerSynced, return nil.
+	if az.nodeInformerSynced == nil {
+		return nil, nil
+	}
+
+	az.nodeCachesLock.RLock()
+	defer az.nodeCachesLock.RUnlock()
+	if !az.nodeInformerSynced() {
+		return nil, fmt.Errorf("node informer is not synced when trying to GetNodeNames")
+	}
+
+	return sets.NewString(az.nodeNames.List()...), nil
+}
+
 // GetResourceGroups returns a set of resource groups that all nodes are running on.
 func (az *Cloud) GetResourceGroups() (sets.String, error) {
 	// Kubelet won't set az.nodeInformerSynced, always return configured resourceGroup.

staging/src/k8s.io/legacy-cloud-providers/azure/azure_test.go

@@ -3244,6 +3244,7 @@ func TestUpdateNodeCaches(t *testing.T) {
 	az.nodeZones = map[string]sets.String{zone: nodesInZone}
 	az.nodeResourceGroups = map[string]string{"prevNode": "rg"}
 	az.unmanagedNodes = sets.NewString("prevNode")
+	az.nodeNames = sets.NewString("prevNode")
 
 	prevNode := v1.Node{
 		ObjectMeta: metav1.ObjectMeta{
@@ -3260,6 +3261,7 @@ func TestUpdateNodeCaches(t *testing.T) {
 	assert.Equal(t, 0, len(az.nodeZones[zone]))
 	assert.Equal(t, 0, len(az.nodeResourceGroups))
 	assert.Equal(t, 0, len(az.unmanagedNodes))
+	assert.Equal(t, 0, len(az.nodeNames))
 
 	newNode := v1.Node{
 		ObjectMeta: metav1.ObjectMeta{
@@ -3276,6 +3278,7 @@ func TestUpdateNodeCaches(t *testing.T) {
 	assert.Equal(t, 1, len(az.nodeZones[zone]))
 	assert.Equal(t, 1, len(az.nodeResourceGroups))
 	assert.Equal(t, 1, len(az.unmanagedNodes))
+	assert.Equal(t, 1, len(az.nodeNames))
 }
 
 func TestGetActiveZones(t *testing.T) {

staging/src/k8s.io/legacy-cloud-providers/azure/azure_vmss.go

@@ -74,7 +74,8 @@ type scaleSet struct {
 	*Cloud
 
 	// availabilitySet is also required for scaleSet because some instances
-	// (e.g. master nodes) may not belong to any scale sets.
+	// (e.g. control plane nodes) may not belong to any scale sets.
+	// this also allows for clusters with both VM and VMSS nodes.
 	availabilitySet VMSet
 
 	vmssCache                 *azcache.TimedCache

staging/src/k8s.io/legacy-cloud-providers/azure/azure_vmss_cache.go

@@ -58,6 +58,11 @@ type vmssEntry struct {
 	lastUpdate    time.Time
 }
 
+type availabilitySetEntry struct {
+	vmNames   sets.String
+	nodeNames sets.String
+}
+
 func (ss *scaleSet) newVMSSCache() (*azcache.TimedCache, error) {
 	getter := func(key string) (interface{}, error) {
 		localCache := &sync.Map{} // [vmssName]*vmssEntry
@@ -278,7 +283,7 @@ func (ss *scaleSet) deleteCacheForNode(nodeName string) error {
 
 func (ss *scaleSet) newAvailabilitySetNodesCache() (*azcache.TimedCache, error) {
 	getter := func(key string) (interface{}, error) {
-		localCache := sets.NewString()
+		vmNames := sets.NewString()
 		resourceGroups, err := ss.GetResourceGroups()
 		if err != nil {
 			return nil, err
@@ -292,11 +297,22 @@ func (ss *scaleSet) newAvailabilitySetNodesCache() (*azcache.TimedCache, error)
 
 			for _, vm := range vmList {
 				if vm.Name != nil {
-					localCache.Insert(*vm.Name)
+					vmNames.Insert(*vm.Name)
 				}
 			}
 		}
 
+		// store all the node names in the cluster when the cache data was created.
+		nodeNames, err := ss.GetNodeNames()
+		if err != nil {
+			return nil, err
+		}
+
+		localCache := availabilitySetEntry{
+			vmNames:   vmNames,
+			nodeNames: nodeNames,
+		}
+
 		return localCache, nil
 	}
 
@@ -318,6 +334,16 @@ func (ss *scaleSet) isNodeManagedByAvailabilitySet(nodeName string, crt azcache.
 		return false, err
 	}
 
-	availabilitySetNodes := cached.(sets.String)
-	return availabilitySetNodes.Has(nodeName), nil
+	cachedNodes := cached.(availabilitySetEntry).nodeNames
+	// if the node is not in the cache, assume the node has joined after the last cache refresh and attempt to refresh the cache.
+	if !cachedNodes.Has(nodeName) {
+		klog.V(2).Infof("Node %s has joined the cluster since the last VM cache refresh, refreshing the cache", nodeName)
+		cached, err = ss.availabilitySetNodesCache.Get(availabilitySetNodesKey, azcache.CacheReadTypeForceRefresh)
+		if err != nil {
+			return false, err
+		}
+	}
+
+	cachedVMs := cached.(availabilitySetEntry).vmNames
+	return cachedVMs.Has(nodeName), nil
 }