aws_eks_node_group can't set min_size of 0

[nairb774]

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Terraform Version

$ terraform -v
Terraform v0.12.26
+ provider.aws v2.68.0
+ provider.template v2.1.2

Affected Resource(s)

• aws_eks_node_group

Terraform Configuration Files

resource "aws_eks_node_group" "eks_node_group" {
  cluster_name    = locals.eks_cluster_name
  node_group_name = locals.eks_node_group_name
  node_role_arn   = locals.eks_worker_role_arn
  instance_types  = [locals.eks_instance_type]
  subnet_ids      = [locals.eks_subnet_id]

  scaling_config {
    desired_size = 0
    min_size = 0
    max_size = 50
  }

  lifecycle {
    ignore_changes = [
      scaling_config[0].desired_size,
    ]
  }
}

Error Output

Error: expected scaling_config.0.min_size to be at least (1), got 0

  on eks-cluster.tf line 1, in resource "aws_eks_node_group" "eks_node_group":
  1: resource "aws_eks_node_group" "eks_node_group" {



Error: expected scaling_config.0.desired_size to be at least (1), got 0

  on eks-cluster.tf line 1, in resource "aws_eks_node_group" "eks_node_group":
  1: resource "aws_eks_node_group" "eks_node_group" {

Expected Behavior

Be able to create the managed node group with a min size, and initial size of 0. The Cluster Autoscaler is able to scale up Node Groups/ASGs with a size of 0, but it is not possible to create such node groups. Ideally, the provider should not validate things that are left unspecified in AWS documentation (see references).

Actual Behavior

Steps to Reproduce

1. terraform apply

The above errors are produced.

Important Factoids

References

• The documentation around creating a managed node group doesn't seem to indicate that 0 is an invalid value. The documentation is actually fairly poor as there isn't any indication of any limits on the values.
• The CLI documentation for create-nodegroup is equally poor.
• The docs for create-auto-scaling-group is no better.

[bflad]

Hi @nairb774 👋 Thank you for submitting this.

The minimum value of 1 is currently enforced by the EKS API and the Terraform AWS Provider is just validating that same limitation. It appears there is an upstream EKS roadmap issue for this available here: aws/containers-roadmap#724

Since the API does not support this currently, I'm going to close this for now since it is inactionable in this codebase, but if they do implement this support in the API we can re-evaluate when that time comes. In the meantime, I would suggest subscribing to and upvoting that roadmap issue or contacting AWS Support with a feature request case. Thanks again.

[ghost]

I'm going to lock this issue because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.

If you feel this issue should be reopened, we encourage creating a new issue linking back to this one for added context. Thanks!