Merge pull request #109706 from alexanderConstantinescu/etp-local-svc

Avoid re-syncing LBs for ETP=local services

staging/src/k8s.io/cloud-provider/controllers/service/controller.go

@@ -98,6 +98,9 @@ type Controller struct {
 	nodeSyncCh chan interface{}
 	// needFullSync indicates if the nodeSyncInternal will do a full node sync on all LB services.
 	needFullSync bool
+	// lastSyncedNodes is used when reconciling node state and keeps track of the last synced set of
+	// nodes. Access to this attribute by multiple go-routines is protected by nodeSyncLock
+	lastSyncedNodes []*v1.Node
 }
 
 // New returns a new service controller to keep cloud provider service resources
@@ -133,6 +136,7 @@ func New(
 		queue:            workqueue.NewNamedRateLimitingQueue(workqueue.NewItemExponentialFailureRateLimiter(minRetryDelay, maxRetryDelay), "service"),
 		// nodeSyncCh has a size 1 buffer. Only one pending sync signal would be cached.
 		nodeSyncCh:      make(chan interface{}, 1),
+		lastSyncedNodes: []*v1.Node{},
 	}
 
 	serviceInformer.Informer().AddEventHandlerWithResyncPeriod(
@@ -176,7 +180,7 @@ func New(
 					return
 				}
 
-				if !shouldSyncNode(oldNode, curNode) {
+				if !shouldSyncUpdatedNode(oldNode, curNode) {
 					return
 				}
 
@@ -257,7 +261,7 @@ func (c *Controller) Run(ctx context.Context, workers int, controllerManagerMetr
 func (c *Controller) triggerNodeSync() {
 	c.nodeSyncLock.Lock()
 	defer c.nodeSyncLock.Unlock()
-	newHosts, err := listWithPredicate(c.nodeLister, c.getNodeConditionPredicate())
+	newHosts, err := listWithPredicates(c.nodeLister, allNodePredicates...)
 	if err != nil {
 		runtime.HandleError(fmt.Errorf("Failed to retrieve current set of nodes from node lister: %v", err))
 		// if node list cannot be retrieve, trigger full node sync to be safe.
@@ -453,7 +457,7 @@ func (c *Controller) syncLoadBalancerIfNeeded(ctx context.Context, service *v1.S
 }
 
 func (c *Controller) ensureLoadBalancer(ctx context.Context, service *v1.Service) (*v1.LoadBalancerStatus, error) {
-	nodes, err := listWithPredicate(c.nodeLister, c.getNodeConditionPredicate())
+	nodes, err := listWithPredicates(c.nodeLister, getNodePredicatesForService(service)...)
 	if err != nil {
 		return nil, err
 	}
@@ -667,6 +671,15 @@ func portEqualForLB(x, y *v1.ServicePort) bool {
 	return true
 }
 
+func serviceKeys(services []*v1.Service) sets.String {
+	ret := sets.NewString()
+	for _, service := range services {
+		key, _ := cache.MetaNamespaceKeyFunc(service)
+		ret.Insert(key)
+	}
+	return ret
+}
+
 func nodeNames(nodes []*v1.Node) sets.String {
 	ret := sets.NewString()
 	for _, node := range nodes {
@@ -682,58 +695,21 @@ func nodeSlicesEqualForLB(x, y []*v1.Node) bool {
 	return nodeNames(x).Equal(nodeNames(y))
 }
 
-func (c *Controller) getNodeConditionPredicate() NodeConditionPredicate {
-	return func(node *v1.Node) bool {
-		if _, hasExcludeBalancerLabel := node.Labels[v1.LabelNodeExcludeBalancers]; hasExcludeBalancerLabel {
-			return false
-		}
-
-		// Remove nodes that are about to be deleted by the cluster autoscaler.
-		for _, taint := range node.Spec.Taints {
-			if taint.Key == ToBeDeletedTaint {
-				klog.V(4).Infof("Ignoring node %v with autoscaler taint %+v", node.Name, taint)
-				return false
-			}
-		}
-
-		// If we have no info, don't accept
-		if len(node.Status.Conditions) == 0 {
-			return false
-		}
-		for _, cond := range node.Status.Conditions {
-			// We consider the node for load balancing only when its NodeReady condition status
-			// is ConditionTrue
-			if cond.Type == v1.NodeReady && cond.Status != v1.ConditionTrue {
-				klog.V(4).Infof("Ignoring node %v with %v condition status %v", node.Name, cond.Type, cond.Status)
-				return false
-			}
-		}
+func shouldSyncUpdatedNode(oldNode, newNode *v1.Node) bool {
+	// Evaluate the individual node exclusion predicate before evaluating the
+	// compounded result of all predicates. We don't sync ETP=local services
+	// for changes on the readiness condition, hence if a node remains NotReady
+	// and a user adds the exclusion label we will need to sync as to make sure
+	// this change is reflected correctly on ETP=local services. The sync
+	// function compares lastSyncedNodes with the new (existing) set of nodes
+	// for each service, so services which are synced with the same set of nodes
+	// should be skipped internally in the sync function. This is needed as to
+	// trigger a global sync for all services and make sure no service gets
+	// skipped due to a changing node predicate.
+	if respectsPredicates(oldNode, nodeIncludedPredicate) != respectsPredicates(newNode, nodeIncludedPredicate) {
 		return true
 	}
-}
-
-func shouldSyncNode(oldNode, newNode *v1.Node) bool {
-	if oldNode.Spec.Unschedulable != newNode.Spec.Unschedulable {
-		return true
-	}
-
-	if !reflect.DeepEqual(oldNode.Labels, newNode.Labels) {
-		return true
-	}
-
-	return nodeReadyConditionStatus(oldNode) != nodeReadyConditionStatus(newNode)
-}
-
-func nodeReadyConditionStatus(node *v1.Node) v1.ConditionStatus {
-	for _, condition := range node.Status.Conditions {
-		if condition.Type != v1.NodeReady {
-			continue
-		}
-
-		return condition.Status
-	}
-
-	return ""
+	return respectsPredicates(oldNode, allNodePredicates...) != respectsPredicates(newNode, allNodePredicates...)
 }
 
 // nodeSyncInternal handles updating the hosts pointed to by all load
@@ -775,24 +751,29 @@ func (c *Controller) nodeSyncInternal(ctx context.Context, workers int) {
 		numServices-len(c.servicesToUpdate), numServices)
 }
 
-// nodeSyncService syncs the nodes for one load balancer type service
-func (c *Controller) nodeSyncService(svc *v1.Service) bool {
+// nodeSyncService syncs the nodes for one load balancer type service. The return value
+// indicates if we should retry. Hence, this functions returns false if we've updated
+// load balancers and finished doing it successfully, or didn't try to at all because
+// there's no need. This function returns true if we tried to update load balancers and
+// failed, indicating to the caller that we should try again.
+func (c *Controller) nodeSyncService(svc *v1.Service, oldNodes, newNodes []*v1.Node) bool {
+	retSuccess := false
+	retNeedRetry := true
 	if svc == nil || !wantsLoadBalancer(svc) {
-		return false
+		return retSuccess
+	}
+	newNodes = filterWithPredicates(newNodes, getNodePredicatesForService(svc)...)
+	oldNodes = filterWithPredicates(oldNodes, getNodePredicatesForService(svc)...)
+	if nodeNames(newNodes).Equal(nodeNames(oldNodes)) {
+		return retSuccess
 	}
 	klog.V(4).Infof("nodeSyncService started for service %s/%s", svc.Namespace, svc.Name)
-	hosts, err := listWithPredicate(c.nodeLister, c.getNodeConditionPredicate())
-	if err != nil {
-		runtime.HandleError(fmt.Errorf("failed to retrieve node list: %v", err))
-		return true
-	}
-
-	if err := c.lockedUpdateLoadBalancerHosts(svc, hosts); err != nil {
+	if err := c.lockedUpdateLoadBalancerHosts(svc, newNodes); err != nil {
 		runtime.HandleError(fmt.Errorf("failed to update load balancer hosts for service %s/%s: %v", svc.Namespace, svc.Name, err))
-		return true
+		return retNeedRetry
 	}
 	klog.V(4).Infof("nodeSyncService finished successfully for service %s/%s", svc.Namespace, svc.Name)
-	return false
+	return retSuccess
 }
 
 // updateLoadBalancerHosts updates all existing load balancers so that
@@ -801,11 +782,20 @@ func (c *Controller) nodeSyncService(svc *v1.Service) bool {
 func (c *Controller) updateLoadBalancerHosts(ctx context.Context, services []*v1.Service, workers int) (servicesToRetry sets.String) {
 	klog.V(4).Infof("Running updateLoadBalancerHosts(len(services)==%d, workers==%d)", len(services), workers)
 
+	// Include all nodes and let nodeSyncService filter and figure out if
+	// the update is relevant for the service in question.
+	nodes, err := listWithPredicates(c.nodeLister)
+	if err != nil {
+		runtime.HandleError(fmt.Errorf("failed to retrieve node list: %v", err))
+		return serviceKeys(services)
+	}
+
 	// lock for servicesToRetry
 	servicesToRetry = sets.NewString()
 	lock := sync.Mutex{}
+
 	doWork := func(piece int) {
-		if shouldRetry := c.nodeSyncService(services[piece]); !shouldRetry {
+		if shouldRetry := c.nodeSyncService(services[piece], c.lastSyncedNodes, nodes); !shouldRetry {
 			return
 		}
 		lock.Lock()
@@ -815,6 +805,7 @@ func (c *Controller) updateLoadBalancerHosts(ctx context.Context, services []*v1
 	}
 
 	workqueue.ParallelizeUntil(ctx, workers, len(services), doWork)
+	c.lastSyncedNodes = nodes
 	klog.V(4).Infof("Finished updateLoadBalancerHosts")
 	return servicesToRetry
 }
@@ -990,19 +981,82 @@ func (c *Controller) patchStatus(service *v1.Service, previousStatus, newStatus
 // some set of criteria defined by the function.
 type NodeConditionPredicate func(node *v1.Node) bool
 
-// listWithPredicate gets nodes that matches predicate function.
-func listWithPredicate(nodeLister corelisters.NodeLister, predicate NodeConditionPredicate) ([]*v1.Node, error) {
+var (
+	allNodePredicates []NodeConditionPredicate = []NodeConditionPredicate{
+		nodeIncludedPredicate,
+		nodeSchedulablePredicate,
+		nodeUnTaintedPredicate,
+		nodeReadyPredicate,
+	}
+	etpLocalNodePredicates []NodeConditionPredicate = []NodeConditionPredicate{
+		nodeIncludedPredicate,
+		nodeSchedulablePredicate,
+		nodeUnTaintedPredicate,
+	}
+)
+
+func getNodePredicatesForService(service *v1.Service) []NodeConditionPredicate {
+	if service.Spec.ExternalTrafficPolicy == v1.ServiceExternalTrafficPolicyTypeLocal {
+		return etpLocalNodePredicates
+	}
+	return allNodePredicates
+}
+
+// We consider the node for load balancing only when the node is not labelled for exclusion.
+func nodeIncludedPredicate(node *v1.Node) bool {
+	_, hasExcludeBalancerLabel := node.Labels[v1.LabelNodeExcludeBalancers]
+	return !hasExcludeBalancerLabel
+}
+
+// We consider the node for load balancing only when the node is schedulable.
+func nodeSchedulablePredicate(node *v1.Node) bool {
+	return !node.Spec.Unschedulable
+}
+
+// We consider the node for load balancing only when its not tainted for deletion by the cluster autoscaler.
+func nodeUnTaintedPredicate(node *v1.Node) bool {
+	for _, taint := range node.Spec.Taints {
+		if taint.Key == ToBeDeletedTaint {
+			return false
+		}
+	}
+	return true
+}
+
+// We consider the node for load balancing only when its NodeReady condition status is ConditionTrue
+func nodeReadyPredicate(node *v1.Node) bool {
+	for _, cond := range node.Status.Conditions {
+		if cond.Type == v1.NodeReady {
+			return cond.Status == v1.ConditionTrue
+		}
+	}
+	return false
+}
+
+// listWithPredicate gets nodes that matches all predicate functions.
+func listWithPredicates(nodeLister corelisters.NodeLister, predicates ...NodeConditionPredicate) ([]*v1.Node, error) {
 	nodes, err := nodeLister.List(labels.Everything())
 	if err != nil {
 		return nil, err
 	}
+	return filterWithPredicates(nodes, predicates...), nil
+}
 
+func filterWithPredicates(nodes []*v1.Node, predicates ...NodeConditionPredicate) []*v1.Node {
 	var filtered []*v1.Node
 	for i := range nodes {
-		if predicate(nodes[i]) {
+		if respectsPredicates(nodes[i], predicates...) {
 			filtered = append(filtered, nodes[i])
 		}
 	}
-
-	return filtered, nil
+	return filtered
+}
+
+func respectsPredicates(node *v1.Node, predicates ...NodeConditionPredicate) bool {
+	for _, p := range predicates {
+		if !p(node) {
+			return false
+		}
+	}
+	return true
 }