Disabling internal load balancing for Azure App Service Environments may lead to lower availability of applications.
Configuration of the Internal Load Balancing for App Service networks can be achieved after configuring some prerequisites, such as creating DNS entries and launching an application gateway. To configure this feature, follow the steps in the Azure documentation (below).
In Terraform -
References:
https://learn.microsoft.com/en-us/azure/app-service/environment/integrate-with-application-gateway#configure-an-application-gateway-integration-with-ilb-ase
https://registry.terraform.io/providers/hashicorp/azurerm/latest/docs/resources/app_service_environment