Request for AWS Global Accelerator support

[mthemis-provenir]

What would you like to be added:
The AWS Load Balancer Controller now supports being able to define and manage an AWS Global Accelerator resource automatically, however there appears to be no way to get external-dns to see that hostname and use it instead of the ALB hostname without manually defining external-dns.alpha.kubernetes.io/target, which is obviously not fault tolerant in case the accelerator ever gets replaced.

In our particular use case, we have an Istio Gateway resource that points to an Ingress resource, which external-dns uses to find the associated hostname.

Ideally, we'd be able to add an annotation that references the <namespace>/<name> of a GlobalAccelerator resource, such that external-dns uses that instead of the ALB name.

This is a simple example of a GlobalAccelerator resource:

apiVersion: aga.k8s.aws/v1beta1
kind: GlobalAccelerator
metadata:
  name: accelerator
  namespace: infrastructure
spec:
  name: accelerator
  ipAddressType: IPV4
  listeners:
    - protocol: TCP
      portRanges:
        - fromPort: 80
          toPort: 80
        - fromPort: 443
          toPort: 443
      clientAffinity: SOURCE_IP
      endpointGroups:
        - endpoints:
            - type: Ingress
              name: istio-external
              namespace: infrastructure

When deployed, the GlobalAccelerator resource has the following fields that can be read by external-dns:

status:
  acceleratorARN: >-
    arn:aws:globalaccelerator::xxx:accelerator/xxx
  conditions:
    - lastTransitionTime: '2026-02-05T16:52:12Z'
      message: GlobalAccelerator is ready and available
      reason: AcceleratorReady
      status: 'True'
      type: Ready
  dnsName: xxx.awsglobalaccelerator.com
  ipSets:
    - ipAddressFamily: IPv4
      ipAddresses:
        - 1.2.3.4
        - 5.6.7.8
  observedGeneration: 1
  status: DEPLOYED

I was thinking perhaps a new annotation can be added to the Ingress that will tell external-dns to look at the accelerator resource for the hostname to use thusly:

  annotations:
    external-dns.alpha.kubernetes.io/global-accelerator: infrastructure/accelerator

If it is solved this way, it should still work with Istio automatically as hopefully external-dns will follow the external-dns.alpha.kubernetes.io/ingress annotation, see the ingress, find the suggested annotation, then look up that resource to find the appropriate dnsName.

Any more questions please let me know and I'd be happy to provide feedback.