Make addEgressNode and deleteEgressNode use caches for pulling EIPs

Since in the previous commit we will always call addEgressNode
for every kubelet update which is every 10seconds for every node,
we must stop using kapi listing for EIPs since this will not
scale well. Let us use the informer caches to pull EIPs and then
unless there are EIPs that have status.items != spec.items
rest will be shortcircuited in this function.

Signed-off-by: Surya Seetharaman <suryaseetharaman.9@gmail.com>

go-controller/pkg/clustermanager/egressip_controller.go

@@ -751,9 +751,9 @@ func (eIPC *egressIPClusterController) addEgressNode(nodeName string) error {
 	// egress IPs which are missing an assignment. If there are, we need to send a
 	// synthetic update since reconcileEgressIP will then try to assign those IPs to
 	// this node (if possible)
-	egressIPs, err := eIPC.kube.GetEgressIPs()
+	egressIPs, err := eIPC.watchFactory.GetEgressIPs()
 	if err != nil {
-		return fmt.Errorf("unable to list EgressIPs, err: %v", err)
+		return fmt.Errorf("unable to fetch EgressIPs, err: %v", err)
 	}
 	for _, egressIP := range egressIPs {
 		egressIP := *egressIP
@@ -793,9 +793,9 @@ func (eIPC *egressIPClusterController) deleteEgressNode(nodeName string) error {
 	// Since the node has been labelled as "not usable" for egress IP
 	// assignments we need to find all egress IPs which have an assignment to
 	// it, and move them elsewhere.
-	egressIPs, err := eIPC.kube.GetEgressIPs()
+	egressIPs, err := eIPC.watchFactory.GetEgressIPs()
 	if err != nil {
-		return fmt.Errorf("unable to list EgressIPs, err: %v", err)
+		return fmt.Errorf("unable to fetch EgressIPs, err: %v", err)
 	}
 	for _, egressIP := range egressIPs {
 		egressIP := *egressIP