Make CIDR allocation retry backoff exponentially

pkg/controller/nodeipam/ipam/cidr_allocator.go

@@ -71,7 +71,10 @@ const (
 	cidrUpdateRetries = 3
 
 	// updateRetryTimeout is the time to wait before requeing a failed node for retry
-	updateRetryTimeout = 100 * time.Millisecond
+	updateRetryTimeout = 250 * time.Millisecond
+
+	// maxUpdateRetryTimeout is the maximum amount of time between timeouts.
+	maxUpdateRetryTimeout = 5 * time.Second
 
 	// updateMaxRetries is the max retries for a failed node
 	updateMaxRetries = 10

pkg/controller/nodeipam/ipam/cloud_cidr_allocator.go

@@ -24,6 +24,7 @@ import (
 
 	"github.com/golang/glog"
 
+	"k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/api/errors"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/types"
@@ -33,7 +34,6 @@ import (
 	"k8s.io/client-go/tools/cache"
 	"k8s.io/client-go/tools/record"
 
-	"k8s.io/api/core/v1"
 	clientset "k8s.io/client-go/kubernetes"
 	"k8s.io/client-go/kubernetes/scheme"
 	v1core "k8s.io/client-go/kubernetes/typed/core/v1"
@@ -155,16 +155,21 @@ func (ca *cloudCIDRAllocator) worker(stopChan <-chan struct{}) {
 				glog.Warning("Channel nodeCIDRUpdateChannel was unexpectedly closed")
 				return
 			}
-			if err := ca.updateCIDRAllocation(workItem); err != nil {
-				if ca.canRetry(workItem) {
-					time.AfterFunc(updateRetryTimeout, func() {
+			if err := ca.updateCIDRAllocation(workItem); err == nil {
+				glog.V(3).Infof("Updated CIDR for %q", workItem)
+				ca.removeNodeFromProcessing(workItem)
+			} else {
+				glog.Errorf("Error updating CIDR for %q: %v", workItem, err)
+				if canRetry, timeout := ca.retryParams(workItem); canRetry {
+					glog.V(2).Infof("Retrying update for %q after %v", workItem, timeout)
+					time.AfterFunc(timeout, func() {
 						// Requeue the failed node for update again.
 						ca.nodeUpdateChannel <- workItem
 					})
 					continue
 				}
+				glog.Errorf("Exceeded retry count for %q, dropping from queue", workItem)
 			}
-			ca.removeNodeFromProcessing(workItem)
 		case <-stopChan:
 			return
 		}
@@ -181,15 +186,34 @@ func (ca *cloudCIDRAllocator) insertNodeToProcessing(nodeName string) bool {
 	return true
 }
 
-func (ca *cloudCIDRAllocator) canRetry(nodeName string) bool {
+func (ca *cloudCIDRAllocator) retryParams(nodeName string) (bool, time.Duration) {
 	ca.lock.Lock()
 	defer ca.lock.Unlock()
-	count := ca.nodesInProcessing[nodeName].retries + 1
+
+	entry, ok := ca.nodesInProcessing[nodeName]
+	if !ok {
+		glog.Errorf("Cannot get retryParams for %q as entry does not exist", nodeName)
+		return false, 0
+	}
+
+	count := entry.retries + 1
 	if count > updateMaxRetries {
-		return false
+		return false, 0
 	}
 	ca.nodesInProcessing[nodeName].retries = count
-	return true
+
+	return true, nodeUpdateRetryTimeout(count)
+}
+
+func nodeUpdateRetryTimeout(count int) time.Duration {
+	timeout := updateRetryTimeout
+	for i := 0; i < count && timeout < maxUpdateRetryTimeout; i++ {
+		timeout *= 2
+	}
+	if timeout > maxUpdateRetryTimeout {
+		return maxUpdateRetryTimeout
+	}
+	return timeout
 }
 
 func (ca *cloudCIDRAllocator) removeNodeFromProcessing(nodeName string) {

pkg/controller/nodeipam/ipam/cloud_cidr_allocator_test.go

@@ -17,6 +17,7 @@ limitations under the License.
 package ipam
 
 import (
+	"fmt"
 	"testing"
 	"time"
 
@@ -57,3 +58,22 @@ func TestBoundedRetries(t *testing.T) {
 		// wait for node to finish processing (should terminate and not time out)
 	}
 }
+
+func TestNodeUpdateRetryTimeout(t *testing.T) {
+	for _, tc := range []struct {
+		count int
+		want  time.Duration
+	}{
+		{count: 0, want: 250 * time.Millisecond},
+		{count: 1, want: 500 * time.Millisecond},
+		{count: 2, want: 1000 * time.Millisecond},
+		{count: 3, want: 2000 * time.Millisecond},
+		{count: 50, want: 5000 * time.Millisecond},
+	} {
+		t.Run(fmt.Sprintf("count %d", tc.count), func(t *testing.T) {
+			if got := nodeUpdateRetryTimeout(tc.count); got != tc.want {
+				t.Errorf("nodeUpdateRetryTimeout(tc.count) = %v; want %v", got, tc.want)
+			}
+		})
+	}
+}