Merge pull request kubernetes-sigs#1087 from lukeprentice202/load-balancing-algorithm-type

Load balancing algorithm for target groups support

Author: k8s-ci-robot

docs/guide/ingress/annotation.md

@@ -455,6 +455,10 @@ Custom attributes to LoadBalancers and TargetGroups can be controlled with follo
  ```
  alb.ingress.kubernetes.io/target-group-attributes: stickiness.enabled=true,stickiness.lb_cookie.duration_seconds=60
  ```
+ - set load balancing algorithm to least outstanding requests
+ ```
+ alb.ingress.kubernetes.io/target-group-attributes: load_balancing.algorithm.type=least_outstanding_requests
+ ```
 
 ## Resource Tags
 ALB Ingress controller will automatically apply following tags to AWS resources(ALB/TargetGroups/SecurityGroups) created.

internal/alb/tg/attributes.go

@@ -18,12 +18,14 @@ const (
 StickinessEnabledKey = "stickiness.enabled"
 StickinessTypeKey = "stickiness.type"
 StickinessLbCookieDurationSecondsKey = "stickiness.lb_cookie.duration_seconds"
+LoadBalancingAlgorithmTypeKey = "load_balancing.algorithm.type"
 
 DeregistrationDelayTimeoutSeconds = 300
 SlowStartDurationSeconds = 0
 StickinessEnabled = false
 StickinessType = "lb_cookie"
 StickinessLbCookieDurationSeconds = 86400
+LoadBalancingAlgorithmType = "round_robin"
 )
 
 // Attributes represents the desired state of attributes for a target group.
@@ -55,6 +57,11 @@ type Attributes struct {
 // considered stale. The range is 1 second to 1 week (604800 seconds). The
 // default value is 1 day (86400 seconds).
 StickinessLbCookieDurationSeconds int64
+
+// LoadBalancingAlgorithmType: load_balancing.algorithm.type - The load balancing algorithm determines
+// how the load balancer selects targets when routing requests. The value is round_robin or
+// least_outstanding_requests. The default is round_robin.
+LoadBalancingAlgorithmType string
 }
 
 func NewAttributes(attrs []*elbv2.TargetGroupAttribute) (a *Attributes, err error) {
@@ -64,6 +71,7 @@ func NewAttributes(attrs []*elbv2.TargetGroupAttribute) (a *Attributes, err erro
 StickinessEnabled: StickinessEnabled,
 StickinessType: StickinessType,
 StickinessLbCookieDurationSeconds: StickinessLbCookieDurationSeconds,
+LoadBalancingAlgorithmType: LoadBalancingAlgorithmType,
 }
 var e error
 for _, attr := range attrs {
@@ -103,6 +111,11 @@ func NewAttributes(attrs []*elbv2.TargetGroupAttribute) (a *Attributes, err erro
 if a.StickinessLbCookieDurationSeconds < 1 || a.StickinessLbCookieDurationSeconds > 604800 {
 return a, fmt.Errorf("%s must be within 1-604800 seconds, not %v", attrKey, attrValue)
 }
+case LoadBalancingAlgorithmTypeKey:
+a.LoadBalancingAlgorithmType = attrValue
+if attrValue != "round_robin" && attrValue != "least_outstanding_requests" {
+return a, fmt.Errorf("invalid target group attribute value %s=%s", attrKey, attrValue)
+}
 default:
 e = NewInvalidAttribute(attrKey)
 }
@@ -180,6 +193,10 @@ func attributesChangeSet(a, b *Attributes) (changeSet []*elbv2.TargetGroupAttrib
 changeSet = append(changeSet, tgAttribute(StickinessLbCookieDurationSecondsKey, fmt.Sprintf("%v", b.StickinessLbCookieDurationSeconds)))
 }
 
+if a.LoadBalancingAlgorithmType != b.LoadBalancingAlgorithmType {
+changeSet = append(changeSet, tgAttribute(LoadBalancingAlgorithmTypeKey, b.LoadBalancingAlgorithmType))
+}
+
 return
 }
 

internal/alb/tg/attributes_test.go

@@ -138,6 +138,18 @@ func Test_NewAttributes(t *testing.T) {
 attributes: []*elbv2.TargetGroupAttribute{tgAttribute(StickinessLbCookieDurationSecondsKey, "error")},
 },
 
+{
+name: "LoadBalancingAlgorithmTypeKey is default",
+ok: true,
+attributes: []*elbv2.TargetGroupAttribute{tgAttribute(LoadBalancingAlgorithmTypeKey, "round_robin")},
+output: MustNewAttributes([]*elbv2.TargetGroupAttribute{tgAttribute(LoadBalancingAlgorithmTypeKey, "round_robin")}),
+},
+{
+name: "LoadBalancingAlgorithmTypeKey is not round_robin or least_outstanding_requests",
+ok: false,
+attributes: []*elbv2.TargetGroupAttribute{tgAttribute(LoadBalancingAlgorithmTypeKey, "error")},
+},
+
 {
 name: "Invalid attribute",
 ok: false,
@@ -290,6 +302,18 @@ func Test_attributesChangeSet(t *testing.T) {
 b: MustNewAttributes([]*elbv2.TargetGroupAttribute{tgAttribute(StickinessLbCookieDurationSecondsKey, "501")}),
 changeSet: []*elbv2.TargetGroupAttribute{tgAttribute(StickinessLbCookieDurationSecondsKey, "501")},
 },
+
+{
+name: "LoadBalancingAlgorithmType: a=default b=default",
+a: MustNewAttributes([]*elbv2.TargetGroupAttribute{tgAttribute(LoadBalancingAlgorithmTypeKey, "round_robin")}),
+b: MustNewAttributes([]*elbv2.TargetGroupAttribute{tgAttribute(LoadBalancingAlgorithmTypeKey, "round_robin")}),
+},
+{
+name: "LoadBalancingAlgorithmType: a=default b=nondefault a!=b",
+a: MustNewAttributes([]*elbv2.TargetGroupAttribute{tgAttribute(LoadBalancingAlgorithmTypeKey, "round_robin")}),
+b: MustNewAttributes([]*elbv2.TargetGroupAttribute{tgAttribute(LoadBalancingAlgorithmTypeKey, "least_outstanding_requests")}),
+changeSet: []*elbv2.TargetGroupAttribute{tgAttribute(LoadBalancingAlgorithmTypeKey, "least_outstanding_requests")},
+},
 } {
 t.Run(tc.name, func(t *testing.T) {
 changeSet := attributesChangeSet(tc.a, tc.b)