Add support for ALB IPv6 target groups

[kishorj]

Issue

Description

Support IPv6 ALB target groups with the following prerequisites:

• k8s cluster ipv6 configuration
• Amazon VPC CNI plugin with IPv6 prefix delegation support
• ALB target group target type IP
• dualstack ALB

Targetgroupbinding CRD

Sample TargetGroupBinding spec with the IP address type

apiVersion: elbv2.k8s.aws/v1beta1
kind: TargetGroupBinding
metadata:
  name: my-tgb
spec:
  serviceRef:
    name: awesome-service # route traffic to the awesome-service
    port: 80
  targetGroupARN: <arn-to-targetGroup>
  ipAddressType: ipv6

spec.ipAddressType
ipAddressType is an optional setting.

• Default to the IP address type of the target group resource
• Validating Webhook ensures IP Address matches the type set on the AWS target group resource
• Field is immutable, enforced via validating webhook
• For controller-created targetgroup bindings, controller chooses the type based on service spec

Load balancer configuration

IPv6 target groups are supported for dual stack load balancers. For ALB, dual-stack support can be configured via the following ingress annotation

alb.ingress.kubernetes.io/ip-address-type: dualstack

For NLB, dual-stack support is configured via the following annotation

service.beta.kubernetes.io/aws-load-balancer-ip-address-type: dualstack

Service spec

For the auto-created target group bindings, the target group protocol is determined based on the service spec. The service spec.ipFamilyPolicy determines which IP protocol family to allow on the service configuration

• SingleStack service can either be IPv6 or IPv4. This is the policy that will be supported in the initial phase.
• PreferDualStack, configure IPv4 or IPv6 target groups based on configuration. [out of scope]
• RequireDualStack, configure both IPv4 and IPv6 target groups. [out of scope]

The immutable spec.ipFamilies field is used to specify which IP family to use for single-stack or the order of IP families for dual-stack.

• ["IPv4"]
• ["IPv6"]
• ["IPv4","IPv6"] (dual stack) [out-of-scope]
• ["IPv6","IPv4"] (dual stack) [out-of-scope]

Listener rules

Listener rules forward traffic to either IPv4 target or IPv6 target based on the service configuration. Support for dual stack is currently out-of scope for this feature.

Limitations

• IPv6 TG support is currently limited to ALB target group of type IP.
• Dual stack support is out of scope for the initial release
• Security group per pods (SGPP) feature will not work with IPv6 addresses

Future Enhancements

Dual stack services will be supported once VPC CNI is able to setup dual-stack pods.

Checklist

• Added tests that cover your change (if possible)
• Added/modified documentation as required (such as the README.md, or the docs directory)
• Manually tested
• Made sure the title of the PR is a good description that can go into the release notes

BONUS POINTS checklist: complete for good vibes and maybe prizes?! 🤯

• Backfilled missing tests for code in same general area 🎉
• Refactored something and made the world a better place 🌟

[k8s-ci-robot]

Skipping CI for Draft Pull Request.
If you want CI signal for your change, please convert it to an actual PR.
You can still manually trigger a test run with /test all

[codecov-commenter]

Codecov Report

Merging #2284 (a141d98) into main (e8ab832) will increase coverage by 0.83%.
The diff coverage is 81.11%.

@@            Coverage Diff             @@
##             main    #2284      +/-   ##
==========================================
+ Coverage   53.38%   54.22%   +0.83%     
==========================================
  Files         136      136              
  Lines        7584     7716     +132     
==========================================
+ Hits         4049     4184     +135     
+ Misses       3219     3214       -5     
- Partials      316      318       +2     

Impacted Files	Coverage Δ
pkg/deploy/elbv2/target_group_binding_manager.go	0.00% <0.00%> (ø)
pkg/deploy/elbv2/target_group_manager.go	46.37% <0.00%> (-0.69%)	⬇️
pkg/model/elbv2/target_group.go	0.00% <ø> (ø)
pkg/model/elbv2/target_group_binding.go	0.00% <ø> (ø)
webhooks/elbv2/targetgroupbinding_validator.go	75.00% <64.86%> (-4.60%)	⬇️
webhooks/elbv2/targetgroupbinding_mutator.go	72.88% <75.00%> (+2.29%)	⬆️
pkg/networking/pod_eni_info_resolver.go	93.06% <89.74%> (-1.06%)	⬇️
pkg/ingress/model_build_target_group.go	72.20% <100.00%> (+2.20%)	⬆️
pkg/service/model_build_target_group.go	85.75% <100.00%> (+1.38%)	⬆️
... and 6 more

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[M00nF1sh]

/lgtm

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

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

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• OWNERS [M00nF1sh,kishorj]

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[kishorj]

/retest

[kishorj]

/retest

[nicoaws]

Is this reflected in the docs?