It picks on the first cidr block from the list of destination_cidr_block of aws_route

Terraform
1

Hello,

I’m trying to put the list of destination_cidr_block for transit gateway route in route table. But it only picks the first cidr_block from the list. And also if there are more than one route table in a vpc, the route is created in only one route table in first availability for eg. ap-south-1a.

here is my modules/main.tf for transit gateway route of module

resource "aws_route" "transit_gateway" {
  count = var.create_vpc && var.create_tgw && length(var.private_subnets) > 0 ? 1 : 0
  
  route_table_id         = element(aws_route_table.private.*.id, count.index)
  destination_cidr_block = var.tgw_cidr[count.index]
  transit_gateway_id         = var.transit_gateway_id

  provider = aws.dst
  timeouts {
    create = "5m"
  }

}

Here is modules/variable.tf for transit gateway route

variable "create_vpc" {
  description = "Controls if VPC should be created (it affects almost all resources)"
  type        = bool
  default     = true
}

variable "create_tgw" {
  description = "Controls if an Transit Gateway is created for public subnets and the related routes that connect them."
  type        = bool
  default     = true
}

variable "private_subnets" {
  description = "A list of private subnets inside the VPC"
  type        = list(string)
  default     = []
}

variable "tgw_cidr" {
  type = list(string)
  default = []
}

variable "transit_gateway_id" {}

VPC module in main.tf

module "vpc3" {
  source  = "./modules"

  name = "vpc3"

  cidr = "10.2.0.0/16"

  azs             = ["ap-south-1a", "ap-south-1b", "ap-south-1c"]
  private_subnets = ["10.2.1.0/24", "10.2.2.0/24", "10.2.3.0/24"]

  enable_ipv6                                    = true
  private_subnet_assign_ipv6_address_on_creation = true
  private_subnet_ipv6_prefixes                   = [0, 1, 2]
  tgw_cidr = ["10.1.0.0/16", "10.10.0.0/16"]
  transit_gateway_id                             = module.tgw.ec2_transit_gateway_id
   providers = {

    aws.dst = aws.chris
  }

}