Lengthening initial backoff time for EndpointSlice controller

pkg/controller/endpointslice/BUILD

@@ -41,6 +41,7 @@ go_library(
         "//staging/src/k8s.io/client-go/tools/record:go_default_library",
         "//staging/src/k8s.io/client-go/util/workqueue:go_default_library",
         "//staging/src/k8s.io/component-base/metrics/prometheus/ratelimiter:go_default_library",
+        "//vendor/golang.org/x/time/rate:go_default_library",
         "//vendor/k8s.io/klog:go_default_library",
         "//vendor/k8s.io/utils/net:go_default_library",
     ],

pkg/controller/endpointslice/endpointslice_controller.go

@@ -20,6 +20,8 @@ import (
 	"fmt"
 	"time"
 
+	"golang.org/x/time/rate"
+
 	v1 "k8s.io/api/core/v1"
 	discovery "k8s.io/api/discovery/v1beta1"
 	apierrors "k8s.io/apimachinery/pkg/api/errors"
@@ -47,13 +49,24 @@ const (
 	// maxRetries is the number of times a service will be retried before it is
 	// dropped out of the queue. Any sync error, such as a failure to create or
 	// update an EndpointSlice could trigger a retry. With the current
-	// rate-limiter in use (5ms*2^(maxRetries-1)) the following numbers
-	// represent the sequence of delays between successive queuings of a
-	// service.
+	// rate-limiter in use (1s*2^(numRetries-1)) the following numbers represent
+	// the sequence of delays between successive queuings of a service.
 	//
-	// 5ms, 10ms, 20ms, 40ms, 80ms, 160ms, 320ms, 640ms, 1.3s, 2.6s, 5.1s,
-	// 10.2s, 20.4s, 41s, 82s
+	// 1s, 2s, 4s, 8s, 16s, 32s, 64s, 128s, 256s, 512s, 1000s (max)
 	maxRetries = 15
+
+	// endpointSliceChangeMinSyncDelay indicates the mininum delay before
+	// queuing a syncService call after an EndpointSlice changes. If
+	// endpointUpdatesBatchPeriod is greater than this value, it will be used
+	// instead. This helps batch processing of changes to multiple
+	// EndpointSlices.
+	endpointSliceChangeMinSyncDelay = 1 * time.Second
+
+	// defaultSyncBackOff is the default backoff period for syncService calls.
+	defaultSyncBackOff = 1 * time.Second
+	// maxSyncBackOff is the max backoff period for syncService calls.
+	maxSyncBackOff = 100 * time.Second
+
 	// controllerName is a unique value used with LabelManagedBy to indicated
 	// the component managing an EndpointSlice.
 	controllerName = "endpointslice-controller.k8s.io"
@@ -80,8 +93,19 @@ func NewController(podInformer coreinformers.PodInformer,
 	endpointslicemetrics.RegisterMetrics()
 
 	c := &Controller{
-		client:           client,
-		queue:            workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "endpoint_slice"),
+		client: client,
+		// This is similar to the DefaultControllerRateLimiter, just with a
+		// significantly higher default backoff (1s vs 5ms). This controller
+		// processes events that can require significant EndpointSlice changes,
+		// such as an update to a Service or Deployment. A more significant
+		// rate limit back off here helps ensure that the Controller does not
+		// overwhelm the API Server.
+		queue: workqueue.NewNamedRateLimitingQueue(workqueue.NewMaxOfRateLimiter(
+			workqueue.NewItemExponentialFailureRateLimiter(defaultSyncBackOff, maxSyncBackOff),
+			// 10 qps, 100 bucket size. This is only for retry speed and its
+			// only the overall factor (not per item).
+			&workqueue.BucketRateLimiter{Limiter: rate.NewLimiter(rate.Limit(10), 100)},
+		), "endpoint_slice"),
 		workerLoopPeriod: time.Second,
 	}
 
@@ -409,7 +433,14 @@ func (c *Controller) queueServiceForEndpointSlice(endpointSlice *discovery.Endpo
 		utilruntime.HandleError(fmt.Errorf("Couldn't get key for EndpointSlice %+v: %v", endpointSlice, err))
 		return
 	}
-	c.queue.Add(key)
+
+	// queue after the max of endpointSliceChangeMinSyncDelay and
+	// endpointUpdatesBatchPeriod.
+	delay := endpointSliceChangeMinSyncDelay
+	if c.endpointUpdatesBatchPeriod > delay {
+		delay = c.endpointUpdatesBatchPeriod
+	}
+	c.queue.AddAfter(key, delay)
 }
 
 func (c *Controller) addPod(obj interface{}) {