add cpu_options to launch template (#159)

* add cpu_options to launch template

* calculate cpu_count

* minor improvements

* terraform fmt

Author: y3ti

README.md

@@ -199,6 +199,7 @@ All those keys are required to be there so if the alarm you are setting does not
 | <a name="input_block_device_mappings"></a> [block\_device\_mappings](#input\_block\_device\_mappings) | Specify volumes to attach to the instance besides the volumes specified by the AMI | <pre>list(object({<br/>    device_name  = optional(string)<br/>    no_device    = optional(bool)<br/>    virtual_name = optional(string)<br/>    ebs = object({<br/>      delete_on_termination = optional(bool)<br/>      encrypted             = optional(bool)<br/>      iops                  = optional(number)<br/>      throughput            = optional(number)<br/>      kms_key_id            = optional(string)<br/>      snapshot_id           = optional(string)<br/>      volume_size           = optional(number)<br/>      volume_type           = optional(string)<br/>    })<br/>  }))</pre> | `[]` | no |
 | <a name="input_capacity_rebalance"></a> [capacity\_rebalance](#input\_capacity\_rebalance) | Indicates whether capacity rebalance is enabled. Otherwise, capacity rebalance is disabled. | `bool` | `false` | no |
 | <a name="input_context"></a> [context](#input\_context) | Single object for setting entire context at once.<br/>See description of individual variables for details.<br/>Leave string and numeric variables as `null` to use default value.<br/>Individual variable settings (non-null) override settings in context object,<br/>except for attributes, tags, and additional\_tag\_map, which are merged. | `any` | <pre>{<br/>  "additional_tag_map": {},<br/>  "attributes": [],<br/>  "delimiter": null,<br/>  "descriptor_formats": {},<br/>  "enabled": true,<br/>  "environment": null,<br/>  "id_length_limit": null,<br/>  "label_key_case": null,<br/>  "label_order": [],<br/>  "label_value_case": null,<br/>  "labels_as_tags": [<br/>    "unset"<br/>  ],<br/>  "name": null,<br/>  "namespace": null,<br/>  "regex_replace_chars": null,<br/>  "stage": null,<br/>  "tags": {},<br/>  "tenant": null<br/>}</pre> | no |
+| <a name="input_cpu_options"></a> [cpu\_options](#input\_cpu\_options) | The CPU options for the instance | <pre>object({<br/>    amd_sev_snp_enabled = optional(bool, null)<br/>    core_count          = optional(number, null)<br/>    threads_per_core    = optional(number, null)<br/><br/>  })</pre> | `null` | no |
 | <a name="input_cpu_utilization_high_evaluation_periods"></a> [cpu\_utilization\_high\_evaluation\_periods](#input\_cpu\_utilization\_high\_evaluation\_periods) | The number of periods over which data is compared to the specified threshold | `number` | `2` | no |
 | <a name="input_cpu_utilization_high_period_seconds"></a> [cpu\_utilization\_high\_period\_seconds](#input\_cpu\_utilization\_high\_period\_seconds) | The period in seconds over which the specified statistic is applied | `number` | `300` | no |
 | <a name="input_cpu_utilization_high_statistic"></a> [cpu\_utilization\_high\_statistic](#input\_cpu\_utilization\_high\_statistic) | The statistic to apply to the alarm's associated metric. Either of the following is supported: `SampleCount`, `Average`, `Sum`, `Minimum`, `Maximum` | `string` | `"Average"` | no |

main.tf

@@ -3,6 +3,14 @@ data "aws_subnet" "this" {
   id       = each.value
 }
 
+data "aws_ec2_instance_type" "default" {
+  count = (
+    var.cpu_options != null && var.cpu_options.threads_per_core != null && var.cpu_options.core_count == null ? 1 : 0
+  )
+
+  instance_type = var.instance_type
+}
+
 resource "aws_launch_template" "default" {
   count = module.this.enabled ? 1 : 0
 
@@ -87,6 +95,22 @@ resource "aws_launch_template" "default" {
     }
   }
 
+  dynamic "cpu_options" {
+    for_each = var.cpu_options != null ? [var.cpu_options] : []
+    content {
+      amd_sev_snp = cpu_options.value.amd_sev_snp_enabled != null ? (cpu_options.value.amd_sev_snp_enabled ? "enabled" : "disabled") : null
+
+      # if threads_per_core is set and core_count is not set, use the default cores from the instance type
+      core_count = (
+        cpu_options.value.core_count != null ? cpu_options.value.core_count : (
+          cpu_options.value.threads_per_core == null ? null : one(data.aws_ec2_instance_type.default[*].default_cores)
+        )
+      )
+
+      threads_per_core = lookup(cpu_options.value, "threads_per_core", null)
+    }
+  }
+
   monitoring {
     enabled = var.enable_monitoring
   }

variables.tf

@@ -515,3 +515,14 @@ variable "instance_reuse_policy" {
   description = "If warm pool and this block are configured, instances in the Auto Scaling group can be returned to the warm pool on scale in. The default is to terminate instances in the Auto Scaling group when the group scales in."
   default     = null
 }
+
+variable "cpu_options" {
+  type = object({
+    amd_sev_snp_enabled = optional(bool, null)
+    core_count          = optional(number, null)
+    threads_per_core    = optional(number, null)
+
+  })
+  description = "The CPU options for the instance"
+  default     = null
+}