From f63ac1962cd6515f16fab4bfddbff09c3f5291a2 Mon Sep 17 00:00:00 2001
From: Zach Loafman <zml@google.com>
Date: Tue, 21 Jun 2016 18:09:31 -0700
Subject: [PATCH] GCE provider: Create TargetPool with 200 instances, then
 update with rest

Tested with 2000 nodes, this actually meets the GCE API specifications
(which is nutty). Previous PR (#25178) was based on a mistaken
understanding of a poorly documented set of limitations, and even
poorer testing, for which I am embarassed.
---
 pkg/cloudprovider/providers/gce/gce.go | 30 +++++++++++++++++++++++---
 1 file changed, 27 insertions(+), 3 deletions(-)

diff --git a/pkg/cloudprovider/providers/gce/gce.go b/pkg/cloudprovider/providers/gce/gce.go
index 0ffcce4527927..92d09ce13be2e 100644
--- a/pkg/cloudprovider/providers/gce/gce.go
+++ b/pkg/cloudprovider/providers/gce/gce.go
@@ -69,6 +69,9 @@ const (
 	// are iterated through to prevent infinite loops if the API
 	// were to continuously return a nextPageToken.
 	maxPages = 25
+
+	// Target Pool creation is limited to 200 instances.
+	maxTargetPoolCreateInstances = 200
 )
 
 // GCECloud is an implementation of Interface, LoadBalancer and Instances for Google Compute Engine.
@@ -537,7 +540,7 @@ func (gce *GCECloud) EnsureLoadBalancer(apiService *api.Service, hostNames []str
 	affinityType := apiService.Spec.SessionAffinity
 
 	serviceName := types.NamespacedName{Namespace: apiService.Namespace, Name: apiService.Name}
-	glog.V(2).Infof("EnsureLoadBalancer(%v, %v, %v, %v, %v, %v, %v)", loadBalancerName, gce.region, loadBalancerIP, portStr, hosts, serviceName, apiService.Annotations)
+	glog.V(2).Infof("EnsureLoadBalancer(%v, %v, %v, %v, %v, %v, %v)", loadBalancerName, gce.region, loadBalancerIP, portStr, hostNames, serviceName, apiService.Annotations)
 
 	// Check if the forwarding rule exists, and if so, what its IP is.
 	fwdRuleExists, fwdRuleNeedsUpdate, fwdRuleIP, err := gce.forwardingRuleNeedsUpdate(loadBalancerName, gce.region, loadBalancerIP, ports)
@@ -706,10 +709,27 @@ func (gce *GCECloud) EnsureLoadBalancer(apiService *api.Service, hostNames []str
 	// Once we've deleted the resources (if necessary), build them back up (or for
 	// the first time if they're new).
 	if tpNeedsUpdate {
-		if err := gce.createTargetPool(loadBalancerName, serviceName.String(), gce.region, hosts, affinityType); err != nil {
+		createInstances := hosts
+		if len(hosts) > maxTargetPoolCreateInstances {
+			createInstances = createInstances[:maxTargetPoolCreateInstances]
+		}
+
+		if err := gce.createTargetPool(loadBalancerName, serviceName.String(), gce.region, createInstances, affinityType); err != nil {
 			return nil, fmt.Errorf("failed to create target pool %s: %v", loadBalancerName, err)
 		}
-		glog.V(4).Infof("EnsureLoadBalancer(%v(%v)): created target pool", loadBalancerName, serviceName)
+		if len(hosts) <= maxTargetPoolCreateInstances {
+			glog.V(4).Infof("EnsureLoadBalancer(%v(%v)): created target pool", loadBalancerName, serviceName)
+		} else {
+			glog.V(4).Infof("EnsureLoadBalancer(%v(%v)): created initial target pool (now updating with %d hosts)", loadBalancerName, serviceName, len(hosts)-maxTargetPoolCreateInstances)
+
+			created := sets.NewString()
+			for _, host := range createInstances {
+				created.Insert(host.makeComparableHostPath())
+			}
+			if err := gce.updateTargetPool(loadBalancerName, created, hosts); err != nil {
+				return nil, fmt.Errorf("failed to update target pool %s: %v", loadBalancerName, err)
+			}
+		}
 	}
 	if tpNeedsUpdate || fwdRuleNeedsUpdate {
 		if err := gce.createForwardingRule(loadBalancerName, serviceName.String(), gce.region, ipAddress, ports); err != nil {
@@ -1155,6 +1175,10 @@ func (gce *GCECloud) UpdateLoadBalancer(service *api.Service, hostNames []string
 		existing.Insert(hostURLToComparablePath(instance))
 	}
 
+	return gce.updateTargetPool(loadBalancerName, existing, hosts)
+}
+
+func (gce *GCECloud) updateTargetPool(loadBalancerName string, existing sets.String, hosts []*gceInstance) error {
 	var toAdd []*compute.InstanceReference
 	var toRemove []*compute.InstanceReference
 	for _, host := range hosts {