Faster eni scaleup (#2744)

Co-authored-by: Joseph Chen <[email protected]>

Author: jchen6585

pkg/ipamd/ipamd.go

@@ -652,7 +652,11 @@ func (c *IPAMContext) updateIPPoolIfRequired(ctx context.Context) {
 	log.Debugf("IP stats - total IPs: %d, assigned IPs: %d, cooldown IPs: %d", stats.TotalIPs, stats.AssignedIPs, stats.CooldownIPs)
 
 	if datastorePoolTooLow {
-		c.increaseDatastorePool(ctx)
+		// Allow for rapid scale up to decrease time it takes for pod to retrieve an ip
+		// but conservative scale down to account for pod churn
+		for datastorePoolStillTooLow := datastorePoolTooLow; datastorePoolStillTooLow; datastorePoolStillTooLow, _ = c.isDatastorePoolTooLow() {
+			c.increaseDatastorePool(ctx)
+		}
 	} else if c.isDatastorePoolTooHigh(stats) {
 		c.decreaseDatastorePool(decreaseIPPoolInterval)
 	}