aws_autoscaling_group -> mixed_instances_policy -> launch_template -> override don't support count

[jippi]

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Terraform Version

terraform -v
Terraform v0.11.10
+ provider.archive v1.1.0
+ provider.aws v1.50.0
+ provider.cloudflare v1.9.0
+ provider.consul v2.2.0
+ provider.datadog v1.6.0
+ provider.null v1.0.0
+ provider.random v2.0.0
+ provider.template v1.0.0
+ provider.vault v1.3.1

Affected Resource(s)

resource "aws_autoscaling_group" "this" {
  name                      = "${var.class}"
  min_size                  = "${var.asg_min_size}"
  max_size                  = "${var.asg_max_size}"
  health_check_grace_period = "${var.asg_health_check_grace_period}"
  health_check_type         = "${var.asg_health_check_type}"
  target_group_arns         = ["${compact(local.target_group_arns)}"]
  vpc_zone_identifier       = ["${var.subnets}"]
  wait_for_capacity_timeout = 0
  default_cooldown          = "${var.asg_default_cooldown}"

  enabled_metrics = [
    "GroupMinSize",
    "GroupMaxSize",
    "GroupDesiredCapacity",
    "GroupInServiceInstances",
    "GroupPendingInstances",
    "GroupStandbyInstances",
    "GroupTerminatingInstances",
    "GroupTotalInstances",
  ]

  mixed_instances_policy {
    launch_template {
      launch_template_specification {
        launch_template_id = "${aws_launch_template.this.id}"
        version            = "$$Latest"
      }

      override {
        count         = "${length(var.instance_types)}"
        instance_type = "${element(var.instance_types, count.index)}"
      }
    }

    instances_distribution {
      on_demand_base_capacity                  = 0
      on_demand_percentage_above_base_capacity = 0
      spot_allocation_strategy                 = "lowest-price"
      spot_instance_pools                      = "${var.spot_instance_pools}"
    }
  }
}

Expected Behavior

My mixed_instances_policy should have $x override created

I replaced

override {
  instance_type = "c5.large"
}
override {
  instance_type = "m5.large"
}
override {
  instance_type = "t3.medium"
}

with

override {
  count         = "${length(var.instance_types)}"
  instance_type = "${element(var.instance_types, count.index)}"
}

my variables.hcl

variable "instance_types" {
  description = "List of instance types to use"
  type        = "list"
  default     = ["t3.large", "m5.large", "c5.xlarge"]
}

expecting to be able to provide instance types as a variable

Actual Behavior

Error: module.web.aws_autoscaling_group.this: mixed_instances_policy.0.launch_template.0.override.0: invalid or unknown key: count

[bflad]

Hi @jippi 👋 Thanks for submitting this.

The count concept in Terraform 0.11's configuration language only applies to the top level resource configuration, to determine a number of resources to manage. Dynamic declaration of configuration blocks within any Terraform resource will be supported in Terraform 0.12 when it is released in the coming months.

A blog post detailing this concept can be found here: https://www.hashicorp.com/blog/hashicorp-terraform-0-12-preview-for-and-for-each

The issue with the specific feature request upstream in Terraform core can be found here: hashicorp/terraform#7034

Since this enhancement will be covered by the upcoming Terraform 0.12 release and requires no action within the provider itself, I'm going to close this issue. 👍

[dushyants]

i got the same issue but i did it in the different way like below:

locals {
  asg_instance_type = {
    asg_instance_type_1 = "t2.small"
    asg_instance_type_2 = "t2.micro"
    asg_instance_type_3 = "t2.medium"
  }
}


  dynamic "override" {
      for_each = "${local.asg_instance_type}"
         content {
            instance_type = "${override.value}"
        }
      }

[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!