Is it possible to assign an existing LoadBalancer for use by Istio IngressGateway?

Currently, we use Terraform to create EKS or GKE clusters in AWS and GCP respectively. Then, we install Istio with istioctl, which creates an Istio IngressGateway and service of type LoadBalancer.

We then need to run some scripts to snag that LoadBalancer public IP or endpoint to point our DNS properly. My manager suggested that we instead create the LoadBalancer (AWS ELB or GCP LoadBalancer) via Terraform, and then have Istio utilize that LoadBalancer instead (it’s important it exists in Terraform so we can set Route53 DNS in Terraform as well). Is that something that is possible (passing in a LoadBalancer ID or whatever for use by Istio), or does Istio always create its own LoadBalancer from scratch? I couldn’t find a simple flag in the docs to pass to istioctl.