Support multiple EBS volume types & set default to less-expensive gp3

main.tf

@@ -77,6 +77,7 @@ resource "aws_instance" "default" {
   root_block_device {
     encrypted   = var.root_block_device_encrypted
     volume_size = var.root_block_device_volume_size
+    volume_type = var.root_block_device_volume_type
   }
 
   # Optional block; skipped if var.ebs_block_device_volume_size is zero

variables.tf

@@ -62,6 +62,16 @@ variable "root_block_device_volume_size" {
   description = "The volume size (in GiB) to provision for the root block device. It cannot be smaller than the AMI it refers to."
 }
 
+variable "root_block_device_volume_type" {
+  type        = string
+  default     = "gp3"
+  description = "The volume type for the EBS root volume"
+  validation {
+    condition = contains(["standard", "gp2", "gp3", "io1", "io2", "sc1", "st1"], var.root_block_device_volume_type)
+    error_message = "The root volume must specify a supported EBS type"
+  }
+}
+
 variable "disable_api_termination" {
   type        = bool
   description = "Enable EC2 Instance Termination Protection"
@@ -156,8 +166,8 @@ variable "security_group_rules" {
     }
   ]
   description = <<-EOT
-    A list of maps of Security Group rules. 
-    The values of map is fully complated with `aws_security_group_rule` resource. 
+    A list of maps of Security Group rules.
+    The values of map is fully complated with `aws_security_group_rule` resource.
     To get more info see https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/security_group_rule .
   EOT
 }