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Merged
k8s-ci-robot merged 1 commit into from
Mar 13, 2026
Merged

Deregister elb targets before registering targets #1328

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25 changes: 13 additions & 12 deletions pkg/providers/v1/aws_loadbalancer.go
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Original file line number Diff line number Diff line change
Expand Up @@ -859,18 +859,7 @@ func (c *Cloud) ensureTargetGroup(ctx context.Context, targetGroup *elbv2types.T

func (c *Cloud) ensureTargetGroupTargets(ctx context.Context, tgARN string, expectedTargets []*elbv2types.TargetDescription, actualTargets []*elbv2types.TargetDescription) error {
targetsToRegister, targetsToDeregister := c.diffTargetGroupTargets(expectedTargets, actualTargets)
if len(targetsToRegister) > 0 {
targetsToRegisterChunks := c.chunkTargetDescriptions(targetsToRegister, defaultRegisterTargetsChunkSize)
for _, targetsChunk := range targetsToRegisterChunks {
req := &elbv2.RegisterTargetsInput{
TargetGroupArn: aws.String(tgARN),
Targets: targetsChunk,
}
if _, err := c.elbv2.RegisterTargets(ctx, req); err != nil {
return fmt.Errorf("error trying to register targets in target group: %q", err)
}
}
}
// deregister targets prior to registering to allow instance replacements when the LB is at max instance capacity
if len(targetsToDeregister) > 0 {
targetsToDeregisterChunks := c.chunkTargetDescriptions(targetsToDeregister, defaultDeregisterTargetsChunkSize)
for _, targetsChunk := range targetsToDeregisterChunks {
Expand All @@ -883,6 +872,18 @@ func (c *Cloud) ensureTargetGroupTargets(ctx context.Context, tgARN string, expe
}
}
}
if len(targetsToRegister) > 0 {
targetsToRegisterChunks := c.chunkTargetDescriptions(targetsToRegister, defaultRegisterTargetsChunkSize)
for _, targetsChunk := range targetsToRegisterChunks {
req := &elbv2.RegisterTargetsInput{
TargetGroupArn: aws.String(tgARN),
Targets: targetsChunk,
}
if _, err := c.elbv2.RegisterTargets(ctx, req); err != nil {
return fmt.Errorf("error trying to register targets in target group: %q", err)
}
}
}
return nil
}

Expand Down
154 changes: 154 additions & 0 deletions pkg/providers/v1/aws_loadbalancer_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -1921,3 +1921,157 @@ func TestCloud_reconcileTargetGroupsAttributes(t *testing.T) {
})
}
}

// Test-specific mock for ELB v2 client that embeds MockedFakeELBV2
type mockELBV2ClientForEnsureTargetGroupTargets struct {
*MockedFakeELBV2

MaxTargets int
NumTargets int
}

func (m *mockELBV2ClientForEnsureTargetGroupTargets) RegisterTargets(ctx context.Context, input *elbv2.RegisterTargetsInput, optFns ...func(*elbv2.Options)) (*elbv2.RegisterTargetsOutput, error) {
m.NumTargets += len(input.Targets)

if m.NumTargets > m.MaxTargets {
return nil, fmt.Errorf("TooManyTargets")
}

return m.MockedFakeELBV2.RegisterTargets(ctx, input, optFns...)
}

func (m *mockELBV2ClientForEnsureTargetGroupTargets) DeregisterTargets(ctx context.Context, input *elbv2.DeregisterTargetsInput, optFns ...func(*elbv2.Options)) (*elbv2.DeregisterTargetsOutput, error) {
m.NumTargets -= len(input.Targets)

return m.MockedFakeELBV2.DeregisterTargets(ctx, input, optFns...)
}

func TestCloud_ensureTargetGroupTargets(t *testing.T) {
testTargetGroupArn := "arn:aws:elasticloadbalancing:us-east-1:123456789012:targetgroup/test-tg/1234567890123456"

tests := []struct {
name string
maxTargets int
expectedTargets []*elbv2types.TargetDescription
actualTargets []*elbv2types.TargetDescription
expectedError string
description string
}{
{
name: "target replacement at max target limit should not fail",
maxTargets: 4,
expectedTargets: []*elbv2types.TargetDescription{
{
Id: aws.String("i-abcdefg1"),
Port: aws.Int32(8080),
},
{
Id: aws.String("i-abcdefg2"),
Port: aws.Int32(8080),
},
{
Id: aws.String("i-abcdefg3"),
Port: aws.Int32(8080),
},
{
Id: aws.String("i-abcdefg4"),
Port: aws.Int32(8080),
},
},
actualTargets: []*elbv2types.TargetDescription{
{
Id: aws.String("i-replacement"),
Port: aws.Int32(8080),
},
{
Id: aws.String("i-abcdefg2"),
Port: aws.Int32(8080),
},
{
Id: aws.String("i-abcdefg3"),
Port: aws.Int32(8080),
},
{
Id: aws.String("i-abcdefg4"),
Port: aws.Int32(8080),
},
},
description: "Function should succeed when replacing an instance for a LB at max capacity",
},
{
name: "exceeding max target limit should fail",
maxTargets: 4,
expectedTargets: []*elbv2types.TargetDescription{
{
Id: aws.String("i-abcdefg1"),
Port: aws.Int32(8080),
},
{
Id: aws.String("i-abcdefg2"),
Port: aws.Int32(8080),
},
{
Id: aws.String("i-abcdefg3"),
Port: aws.Int32(8080),
},
{
Id: aws.String("i-abcdefg4"),
Port: aws.Int32(8080),
},
{
Id: aws.String("i-abcdefg5"),
Port: aws.Int32(8080),
},
},
actualTargets: []*elbv2types.TargetDescription{
{
Id: aws.String("i-replacement"),
Port: aws.Int32(8080),
},
{
Id: aws.String("i-abcdefg2"),
Port: aws.Int32(8080),
},
{
Id: aws.String("i-abcdefg3"),
Port: aws.Int32(8080),
},
{
Id: aws.String("i-abcdefg4"),
Port: aws.Int32(8080),
},
},
expectedError: "TooManyTargets",
description: "Function should fail when adding an instance to a LB at max capacity",
},
}

for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
mockClient := &mockELBV2ClientForEnsureTargetGroupTargets{
MockedFakeELBV2: &MockedFakeELBV2{
LoadBalancers: []*elbv2types.LoadBalancer{},
TargetGroups: []*elbv2types.TargetGroup{},
Listeners: []*elbv2types.Listener{},
LoadBalancerAttributes: make(map[string]map[string]string),
Tags: make(map[string][]elbv2types.Tag),
RegisteredInstances: make(map[string][]string),
},
MaxTargets: tt.maxTargets,
NumTargets: len(tt.actualTargets),
}
c := &Cloud{
elbv2: mockClient,
}

err := c.ensureTargetGroupTargets(context.TODO(), testTargetGroupArn, tt.expectedTargets, tt.actualTargets)

if len(tt.expectedError) > 0 {
assert.Error(t, err, "Expected error for test case: %s", tt.description)
assert.Contains(t, err.Error(), tt.expectedError, "Error message should contain expected text for test case: %s", tt.description)
} else {
assert.NoError(t, err, "Expected no error for test case: %s", tt.description)
}
})
}
}