Enable dynamic AMI ID input based on the OS type specified

Author: burmek

comet-infrastructure/main.tf

@@ -2,7 +2,7 @@ data "aws_availability_zones" "available" {}
 
 data "aws_eks_cluster_auth" "this" {
   count = var.enable_eks ? 1 : 0
-  name = module.comet_eks[0].cluster_name
+  name  = module.comet_eks[0].cluster_name
 }
 
 locals {
@@ -13,8 +13,8 @@ locals {
   #set environment here, and use local.environment for the environment variables in all of the module calls
 
   tags = {
-    Terraform = "true"
-    Environment       = var.environment
+    Terraform   = "true"
+    Environment = var.environment
   }
 }
 
@@ -55,7 +55,7 @@ module "comet_ec2" {
 
   vpc_id                   = module.vpc.vpc_id
   comet_ec2_subnet         = module.vpc.public_subnets[count.index % length(module.vpc.public_subnets)]
-  comet_ec2_ami            = var.comet_ec2_ami
+  comet_ec2_ami_type       = var.comet_ec2_ami_type
   comet_ec2_instance_type  = var.comet_ec2_instance_type
   comet_ec2_instance_count = var.comet_ec2_instance_count
   comet_ec2_volume_type    = var.comet_ec2_volume_type

comet-infrastructure/modules/comet_ec2/main.tf

@@ -11,8 +11,127 @@ locals {
   }
 }
 
+data "aws_ami" "al2" {
+  most_recent = true
+
+  filter {
+    name   = "name"
+    values = ["amzn2-ami-hvm-*-x86_64-gp2"]
+  }
+
+  filter {
+    name   = "root-device-type"
+    values = ["ebs"]
+  }
+
+  owners = ["amazon"]
+}
+
+data "aws_ami" "rhel7" {
+  most_recent = true
+
+  filter {
+    name   = "name"
+    values = ["RHEL-7*_HVM-*"]
+  }
+
+  filter {
+    name   = "root-device-type"
+    values = ["ebs"]
+  }
+
+  owners = ["amazon"]
+}
+
+data "aws_ami" "rhel8" {
+  most_recent = true
+
+  filter {
+    name   = "name"
+    values = ["RHEL-8*_HVM-*"]
+  }
+
+  filter {
+    name   = "root-device-type"
+    values = ["ebs"]
+  }
+
+  owners = ["amazon"]
+}
+
+data "aws_ami" "rhel9" {
+  most_recent = true
+
+  filter {
+    name   = "name"
+    values = ["RHEL-9*_HVM-*"]
+  }
+
+  filter {
+    name   = "root-device-type"
+    values = ["ebs"]
+  }
+
+  owners = ["amazon"]
+}
+
+data "aws_ami" "ubuntu18" {
+  most_recent = true
+
+  filter {
+    name   = "name"
+    values = ["ubuntu/images/hvm-ssd/ubuntu-*-18.04-amd64-server-*"]
+  }
+
+  filter {
+    name   = "root-device-type"
+    values = ["ebs"]
+  }
+
+  owners = ["amazon"]
+}
+
+data "aws_ami" "ubuntu20" {
+  most_recent = true
+
+  filter {
+    name   = "name"
+    values = ["ubuntu/images/hvm-ssd/ubuntu-*-20.04-amd64-server-*"]
+  }
+
+  filter {
+    name   = "root-device-type"
+    values = ["ebs"]
+  }
+
+  owners = ["amazon"]
+}
+
+data "aws_ami" "ubuntu22" {
+  most_recent = true
+
+  filter {
+    name   = "name"
+    values = ["ubuntu/images/hvm-ssd/ubuntu-*-22.04-amd64-server-*"]
+  }
+
+  filter {
+    name   = "root-device-type"
+    values = ["ebs"]
+  }
+
+  owners = ["amazon"]
+}
+
 resource "aws_instance" "comet_ec2" {
-  ami                    = var.comet_ec2_ami
+  ami                    = var.comet_ec2_ami_type == "al2" ? data.aws_ami.al2.id : (
+                           var.comet_ec2_ami_type == "rhel7" ? data.aws_ami.rhel7.id : (
+                           var.comet_ec2_ami_type == "rhel8" ? data.aws_ami.rhel8.id : (
+                           var.comet_ec2_ami_type == "rhel9" ? data.aws_ami.rhel9.id : (
+                           var.comet_ec2_ami_type == "ubuntu18" ? data.aws_ami.ubuntu18.id : (
+                           var.comet_ec2_ami_type == "ubuntu20" ? data.aws_ami.ubuntu20.id : (
+                           var.comet_ec2_ami_type == "ubuntu22" ? data.aws_ami.ubuntu22.id : (
+                           null)))))))
   instance_type          = var.comet_ec2_instance_type
   key_name               = var.comet_ec2_key
   count                  = var.comet_ec2_instance_count

comet-infrastructure/modules/comet_ec2/variables.tf

@@ -21,8 +21,8 @@ variable "vpc_id" {
   type        = string
 }
 
-variable "comet_ec2_ami" {
-  description = "AMI for the EC2 instance"
+variable "comet_ec2_ami_type" {
+  description = "Operating system type for the EC2 instance AMI"
   type        = string
 }
 

comet-infrastructure/variables.tf

@@ -48,10 +48,14 @@ variable "comet_ec2_subnet" {
   default     = null
 }
 
-variable "comet_ec2_ami" {
-  description = "AMI for Comet EC2 instance"
+variable "comet_ec2_ami_type" {
   type        = string
-  default     = "ami-05842f1afbf311a43"
+  description = "Operating system type for the EC2 instance AMI"
+  default     = "ubuntu22"
+  validation {
+    condition     = can(regex("^al2$|^rhel(7|8|9)$|^ubuntu(18|20|22)$", var.comet_ec2_ami_type))
+    error_message = "Invalid OS type. Allowed values are 'al2', 'rhel7', 'rhel8', 'rhel9', 'ubuntu18', 'ubuntu20', 'ubuntu22'."
+  }
 }
 
 variable "comet_ec2_instance_type" {