Attaching Route53 Alias record to the existing ALB via Service or Istio VirtualService annotation.

[mikhail-khodorovskiy]

What would you like to be added: We have use cases when on a new service deploy, the Route53 A record needs to be added to the existing ALB's Alias record. The order of operation is this:

• lookup the ALB to which attach the record by a known tag
• create A record pointing to the HOST name of the ALB looked up above

Here is the terraform that does this

data "aws_route53_zone" "env_zone" {
  name         = "dev.test.io."
  private_zone = false
}

data "aws_lb" "external_ingress_alb" {
  tags       = var.ingress_alb_tag
}

resource "aws_route53_record" "eks_service_record" {
  zone_id = data.aws_route53_zone.env_zone.zone_id
  name    = "test-service.dev.test.io"
  type    = "A"

  alias {
    name                    = data.aws_lb.external_ingress_alb.dns_name
    zone_id                = data.aws_lb.external_ingress_alb.zone_id
    evaluate_target_health = false
  }
}

Istio Gateway/Virtual service SNI routing forwards to the correct VirtualService?service via the ALB/Ingress as long as the A record for the same hostname attached to the ALB.

Why is this needed: Simplifies the deploy process and allows our pipeline to remove the terraform step above.