Support target node labels for ingress

[kishorj]

Add support for target node labels for ingress resources. This label will allow the user to register the matching nodes in the target group. The labels are specified via the following StringMap annotation -

alb.ingress.kubernetes.io/target-node-labels

This annotation can be specified in the ingress or the service resources. The annotation on the service resource has preference over ingress. This annotation is significant in case of instance targets, and is ignored for ip targets.

Testing done

• Without this annotation, the default filter gets applied
• When ingress/service has this annotation, only the matching nodes get registered
• The annotation on service has preference over the one on the ingress
• On ingress/service edit, any nodes not matching the labels get de-registered from the target group
• When a node resource gets modified, the target group gets reconciled as expected

[codecov-io]

Codecov Report

Merging #1874 (2603b2c) into main (436c3d2) will increase coverage by 0.09%.
The diff coverage is 88.88%.

@@            Coverage Diff             @@
##             main    #1874      +/-   ##
==========================================
+ Coverage   48.07%   48.16%   +0.09%     
==========================================
  Files         112      112              
  Lines        6232     6247      +15     
==========================================
+ Hits         2996     3009      +13     
- Misses       2961     2962       +1     
- Partials      275      276       +1     

Impacted Files	Coverage Δ
pkg/ingress/model_build_target_group.go	73.28% <88.88%> (+0.81%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 436c3d2...2603b2c. Read the comment docs.

[M00nF1sh]

/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: kishorj, M00nF1sh

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [M00nF1sh,kishorj]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment