subnet_ids discarded without warning

[chrisbecke]

Description

Please provide a clear and concise description of the issue you are encountering, and a reproduction of your configuration (see the examples/* directory for references that you can copy+paste and tailor to match your configs if you are unable to copy your exact configuration). The reproduction MUST be executable by running terraform init && terraform apply without any further changes.

If your request is for a new feature, please use the Feature request template.

• ✋ I have searched the open/closed issues and my issue IS not listed.

Versions

• Module version: 21.15.1

Reproduction Code

module "eks" {
  source  = "terraform-aws-modules/eks/aws"
  version = "~> 21.15"

  name                     = var.cluster_name
  vpc_id                   = module.vpc.vpc_id
  subnet_ids               = module.vpc.private_subnets
  control_plane_subnet_ids = module.vpc.intra_subnets

  endpoint_public_access = true

  compute_config = {
    enabled    = true
    node_pools = ["system"]
  }
}

Expected behavior

A warning that controle_plane_subnet_ids will not have the desired results when node_pools is not empty.

Actual behavior

The system nodepool nodes are created in the intra subnet.

Additional context

This is easily understood upon reading the module source: subnet_ids is simply discarded.

  vpc_config {
    security_group_ids      = compact(distinct(concat(var.additional_security_group_ids, [local.security_group_id])))
    subnet_ids              = coalescelist(var.control_plane_subnet_ids, var.subnet_ids)

Thats fine, but then

1. Call this behaviour out in the documentation and or variable comments. Reading the source should not be a requirement to understand how to use the module properly.
2. Why have two subnet fields at all then. They are used literally nowhere else.