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fix: Resource tags don't propagate to frontend NLB #4279 #4328

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Merged
merged 1 commit into from
Sep 4, 2025
Merged

fix: Resource tags don't propagate to frontend NLB #4279 #4328

merged 1 commit into from
Sep 4, 2025
+335 −11

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praddy26
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Issue

Closes #4279

Description

This PR implements tag propagation from Application Load Balancer (ALB) to frontend Network Load Balancer (NLB) in the AWS Load Balancer Controller. The changes provide two ways to handle tags for frontend NLBs:

  1. Frontend NLB-specific tags: Using the new annotation alb.ingress.kubernetes.io/frontend-nlb-tags to specify tags that should be applied only to the frontend NLB
  2. ALB tag propagation: If no frontend-NLB specific tags are specified, the tags from ALB (specified via alb.ingress.kubernetes.io/tags) are automatically propagated to the frontend NLB

Key features implemented:

  • New annotation support for frontend NLB-specific tags
  • Automatic tag propagation from ALB when no specific NLB tags are provided
  • Consistency checks to ensure matching tags across ingress group members
  • Error handling for tag conflicts between group members

Implementation details:

  • Added tag parsing and validation in the buildFrontendNlbTags function
  • Implemented conflict detection for tags between ingress group members
  • Maintains backward compatibility by falling back to ALB tags when no NLB-specific tags are provided

Example usage:

# Specifying NLB-specific tags
annotations:
  alb.ingress.kubernetes.io/frontend-nlb-tags: Environment=prod,Team=platform

# Using ALB tags that will propagate to NLB
annotations:
  alb.ingress.kubernetes.io/tags: Environment=prod,Team=platform

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  • ✅ login: praddy26 / name: Pradeep Lakshmi Narasimha (1b5b4b9)

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Hi @praddy26. Thanks for your PR.

I'm waiting for a kubernetes-sigs member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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@k8s-ci-robot k8s-ci-robot added needs-ok-to-test Indicates a PR that requires an org member to verify it is safe to test. cncf-cla: no Indicates the PR's author has not signed the CNCF CLA. size/L Denotes a PR that changes 100-499 lines, ignoring generated files. labels Aug 30, 2025
@praddy26 praddy26 force-pushed the fix-4279-resource-tags-propogation branch from 6762ff5 to 1f48e38 Compare August 30, 2025 12:54
@k8s-ci-robot k8s-ci-robot added cncf-cla: yes Indicates the PR's author has signed the CNCF CLA. and removed cncf-cla: no Indicates the PR's author has not signed the CNCF CLA. labels Aug 30, 2025
@praddy26 praddy26 force-pushed the fix-4279-resource-tags-propogation branch from 1f48e38 to 3b1f87b Compare August 30, 2025 15:52
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/test

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@praddy26: Cannot trigger testing until a trusted user reviews the PR and leaves an /ok-to-test message.

In response to this:

/test

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/ok-to-test

@k8s-ci-robot k8s-ci-robot added ok-to-test Indicates a non-member PR verified by an org member that is safe to test. and removed needs-ok-to-test Indicates a PR that requires an org member to verify it is safe to test. labels Sep 2, 2025
zac-nixon
zac-nixon reviewed Sep 2, 2025
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pkg/ingress/model_build_frontend_nlb.go
}

// If no frontend-nlb specific tags are found, use the ALB tags
if frontendNlbTags == nil {
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Instead of redefining the logic to generate ALB tags, can you re-use this function?
https://github.com/kubernetes-sigs/aws-load-balancer-controller/blob/main/pkg/ingress/model_build_load_balancer.go#L399-L405

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Thanks for pointing that out @zac-nixon. I have updated the code to re-use the same.

@praddy26 praddy26 force-pushed the fix-4279-resource-tags-propogation branch 3 times, most recently from 4d4b18f to f48d163 Compare September 3, 2025 10:26
@praddy26 praddy26 force-pushed the fix-4279-resource-tags-propogation branch from f48d163 to 1b5b4b9 Compare September 3, 2025 10:28
@praddy26 praddy26 requested a review from zac-nixon September 3, 2025 13:37
@zac-nixon zac-nixon mentioned this pull request Sep 4, 2025
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zac-nixon
zac-nixon approved these changes Sep 4, 2025
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/lgtm
/approved

@k8s-ci-robot k8s-ci-robot added the lgtm "Looks good to me", indicates that a PR is ready to be merged. label Sep 4, 2025
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[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: praddy26, zac-nixon

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@k8s-ci-robot k8s-ci-robot added the approved Indicates a PR has been approved by an approver from all required OWNERS files. label Sep 4, 2025
@k8s-ci-robot k8s-ci-robot merged commit 9ff2282 into kubernetes-sigs:main Sep 4, 2025
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Resource tags don't propagate to frontend NLB
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