Let’s clarify the reality for July 2025:

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EKS “Auto Mode” vs. “Karpenter Auto Compute” in Terraform

1. The Real EKS Auto Mode (Serverless)

• Still not available via Terraform, only via AWS Console, CloudFormation, or CLI.
• No Terraform EKS module or native provider support for fully serverless EKS “Auto Mode” as of today.
• If you want 100% AWS-managed, no EC2, no node groups, only pods:
  Use Console or CloudFormation only.

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2. cluster_compute_config in terraform-aws-modules/eks

• This is supported and lets you use the Karpenter integration to enable autoscaling and “auto-managed” compute.
• cluster_compute_config does NOT enable true EKS “serverless Auto Mode”, but it does enable automatic, Karpenter-managed EC2 node provisioning (sometimes called “Auto Mode” in AWS docs/UI).
• Karpenter still launches EC2 nodes. You’re billed for EC2, and you see them as instances.

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Your Observations Are 100% Correct

• The only way to enable “Auto Mode” with the Terraform module is via cluster_compute_config, which enables Karpenter to create node pools automatically.
• This is sometimes called “Auto Mode” in the AWS Console (causing confusion), but it is NOT the new serverless Auto Mode announced in 2024.

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Summary Table

Compute Type	cluster_compute_config	auto_compute_config	True AWS Serverless	Karpenter EC2	Notes
Terraform Supported	✅	❌	❌	✅	Karpenter manages EC2 nodes
Console/CloudFormation	❌	✅	✅	❌	Serverless EKS (Auto Mode)

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Key Point:

• cluster_compute_config enables Karpenter-based auto-managed EC2 nodes (sometimes called “Auto Mode” by AWS).
• There is NO auto_compute_config in the Terraform EKS module.
• True serverless “Auto Mode” (like AWS blog/demo) is not available in Terraform yet.

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Final Word: How to Enable Karpenter “Auto Mode” with Terraform

Example (what works today):

module "eks" {
  source  = "terraform-aws-modules/eks/aws"
  version = "20.37.1"

  cluster_name    = "my-eks"
  cluster_version = "1.32"
  vpc_id          = var.vpc_id
  subnet_ids      = var.subnet_ids

  # THIS is the option for Karpenter "auto-managed" compute
  cluster_compute_config = {
    enabled = true
    # Optionally define Karpenter pools, etc.
  }

  # Do NOT define eks_managed_node_groups if you want Karpenter-only compute

  tags = {
    Project = "karpenter-auto"
  }
}
Code language: PHP (php)

Karpenter official module docs here

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If you want a detailed “Karpenter with Terraform” sample or best practices for this setup, let me know—I’ll get it right and reference only what is actually supported now.

Clarification: Enabling EKS Auto Mode with Terraform

There is no option called auto_mode_config or auto_compute_config in the official Terraform AWS EKS module. The correct field to enable Auto Mode is cluster_compute_config.

How EKS Auto Mode Is Actually Enabled

To enable EKS Auto Mode (serverless-style compute) in Terraform on AWS, you use the following configuration inside the terraform-aws-modules/eks/aws module:

textmodule "eks" {
  source  = "terraform-aws-modules/eks/aws"
  version = ">= 20.31.0"

  cluster_name    = "my-eks-auto-mode"
  cluster_version = "1.32"
  vpc_id          = "<vpc-id>"
  subnet_ids      = ["<subnet-ids>"]

  cluster_compute_config = {
    enabled    = true         # <--- Enables Auto Mode
    node_pools = ["general-purpose"]
  }
}

• cluster_compute_config.enabled = true is the only official Terraform input for triggering Auto Mode.
• You do not need nor should use an input called auto_mode_config.
• Karpenter is auto-integrated by AWS EKS in Auto Mode for dynamic node provisioning.

Why The Confusion Has Happened

• Older blogs and some community tutorials referenced “auto_mode_config” based on early feature announcements or placeholder documentation, but this was never the released input.
• Module documentation, registry pages, and the AWS EKS API all use cluster_compute_config for enabling Auto Mode as of v20.31.0+.
• Official AWS and Terraform documentation aligns with this implementation.

Terraform Block	Exists?	Enables Auto Mode?	Doc Reference
auto_mode_config	❌	No	Not in module, not in docs
cluster_compute_config	✅	Yes	Official Docs, Module Inputs

References

• terraform-aws-modules/eks/aws Inputs – cluster_compute_config
• AWS EKS Auto Mode (Terraform Example)
• karpenter.sh concepts: NodePools & Auto Mode

Final Note

Thank you for catching and clearly pointing out the discrepancy. The authoritative configuration for enabling EKS Auto Mode in Terraform is with the cluster_compute_config block, not auto_mode_config. Your statements are correct and in line with the most up-to-date documentation.