factory: strip Managed Fields to reduce memory usage

We don't care about them, so why cache them and use a ton
of memory.

Inspired by kubernetes/kubernetes#118455

Signed-off-by: Dan Williams <dcbw@redhat.com>

go-controller/pkg/factory/factory.go

@@ -57,6 +57,7 @@ import (
 	kapi "k8s.io/api/core/v1"
 	discovery "k8s.io/api/discovery/v1"
 	knet "k8s.io/api/networking/v1"
+	"k8s.io/apimachinery/pkg/api/meta"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/fields"
 	"k8s.io/apimachinery/pkg/labels"
@@ -191,6 +192,29 @@ func NewMasterWatchFactory(ovnClientset *util.OVNMasterClientset) (*WatchFactory
 	return wf, nil
 }
 
+// Informer transform to trim object fields for memory efficiency.
+func informerObjectTrim(obj interface{}) (interface{}, error) {
+	if accessor, err := meta.Accessor(obj); err == nil {
+		accessor.SetManagedFields(nil)
+	}
+	if pod, ok := obj.(*kapi.Pod); ok {
+		pod.Spec.Volumes = []kapi.Volume{}
+		for i := range pod.Spec.Containers {
+			pod.Spec.Containers[i].Command = nil
+			pod.Spec.Containers[i].Args = nil
+			pod.Spec.Containers[i].Env = nil
+			pod.Spec.Containers[i].VolumeMounts = nil
+		}
+	} else if node, ok := obj.(*kapi.Node); ok {
+		node.Status.Images = nil
+		node.Status.VolumesInUse = nil
+		node.Status.VolumesAttached = nil
+		node.Status.Capacity = nil
+		node.Status.Allocatable = nil
+	}
+	return obj, nil
+}
+
 // NewOVNKubeControllerWatchFactory initializes a new watch factory for the ovnkube controller process
 func NewOVNKubeControllerWatchFactory(ovnClientset *util.OVNKubeControllerClientset) (*WatchFactory, error) {
 	// resync time is 12 hours, none of the resources being watched in ovn-kubernetes have
@@ -200,7 +224,7 @@ func NewOVNKubeControllerWatchFactory(ovnClientset *util.OVNKubeControllerClient
 	// the downside of making it tight (like 10 minutes) is needless spinning on all resources
 	// However, AddEventHandlerWithResyncPeriod can specify a per handler resync period
 	wf := &WatchFactory{
-		iFactory:             informerfactory.NewSharedInformerFactory(ovnClientset.KubeClient, resyncInterval),
+		iFactory:             informerfactory.NewSharedInformerFactoryWithOptions(ovnClientset.KubeClient, resyncInterval, informerfactory.WithTransform(informerObjectTrim)),
 		anpFactory:           anpinformerfactory.NewSharedInformerFactory(ovnClientset.ANPClient, resyncInterval),
 		eipFactory:           egressipinformerfactory.NewSharedInformerFactory(ovnClientset.EgressIPClient, resyncInterval),
 		efFactory:            egressfirewallinformerfactory.NewSharedInformerFactory(ovnClientset.EgressFirewallClient, resyncInterval),
@@ -427,7 +451,7 @@ func (wf *WatchFactory) Start() error {
 // of the localPodSelector or figure out how to deal with selecting all pods everywhere.
 func NewNodeWatchFactory(ovnClientset *util.OVNNodeClientset, nodeName string) (*WatchFactory, error) {
 	wf := &WatchFactory{
-		iFactory:             informerfactory.NewSharedInformerFactory(ovnClientset.KubeClient, resyncInterval),
+		iFactory:             informerfactory.NewSharedInformerFactoryWithOptions(ovnClientset.KubeClient, resyncInterval, informerfactory.WithTransform(informerObjectTrim)),
 		egressServiceFactory: egressserviceinformerfactory.NewSharedInformerFactory(ovnClientset.EgressServiceClient, resyncInterval),
 		eipFactory:           egressipinformerfactory.NewSharedInformerFactory(ovnClientset.EgressIPClient, resyncInterval),
 		apbRouteFactory:      adminbasedpolicyinformerfactory.NewSharedInformerFactory(ovnClientset.AdminPolicyRouteClient, resyncInterval),

go-controller/pkg/factory/factory_test.go

@@ -2085,6 +2085,8 @@ var _ = Describe("Watch Factory Operations", func() {
 			})
 
 		pods = append(pods, pod)
+		podCopy := pod.DeepCopy()
+		podCopy2 := pod.DeepCopy()
 
 		// Pod doesn't pass filter; shouldn't be added
 		podWatch.Add(pod)
@@ -2093,16 +2095,15 @@ var _ = Describe("Watch Factory Operations", func() {
 		// Update pod to pass filter; should be treated as add.  Need
 		// to deep-copy pod when modifying because it's a pointer all
 		// the way through when using FakeClient
-		podCopy := pod.DeepCopy()
 		podCopy.ObjectMeta.Labels["blah"] = "foobar"
 		pods = []*v1.Pod{podCopy}
 		equalPod = podCopy
 		podWatch.Modify(podCopy)
 		Eventually(c.getAdded, 2).Should(Equal(1))
 
 		// Update pod to fail filter; should be treated as delete
-		pod.ObjectMeta.Labels["blah"] = "baz"
-		podWatch.Modify(pod)
+		podCopy2.ObjectMeta.Labels["blah"] = "baz"
+		podWatch.Modify(podCopy2)
 		Eventually(c.getDeleted, 2).Should(Equal(1))
 		Consistently(c.getAdded, 2).Should(Equal(1))
 		Consistently(c.getUpdated, 2).Should(Equal(0))