cluster-autoscaler.tf

# taken and adapted from here to get it working:
# https://github.com/terraform-aws-modules/terraform-aws-eks/blob/master/docs/autoscaling.md

resource "aws_iam_role_policy_attachment" "workers_autoscaling" {
  policy_arn = aws_iam_policy.worker_autoscaling.arn
  role       = module.eks.worker_iam_role_name
}

resource "aws_iam_policy" "worker_autoscaling" {
  name_prefix = "ClusterAutoScalingPolicy-${var.cluster_name}"
  description = "EKS worker node autoscaling policy for cluster ${var.cluster_name}"
  policy      = data.aws_iam_policy_document.worker_autoscaling.json
  path        = var.iam_path
}

data "aws_iam_policy_document" "worker_autoscaling" {
  statement {
    sid    = "eksWorkerAutoscalingAll"
    effect = "Allow"

    actions = [
      "autoscaling:DescribeAutoScalingGroups",
      "autoscaling:DescribeAutoScalingInstances",
      "autoscaling:DescribeLaunchConfigurations",
      "autoscaling:DescribeTags",
      "ec2:DescribeLaunchTemplateVersions",
      "autoscaling:SetDesiredCapacity",
      "autoscaling:TerminateInstanceInAutoScalingGroup",
      "autoscaling:UpdateAutoScalingGroup",
    ]

    resources = ["*"]
  }
}