Fixed issues where certain AZs did not support ARM instances

Author: RussellGilmore

README.md

@@ -65,12 +65,13 @@ No modules.
 | [aws_route53_record.red_instance_dns](https://registry.terraform.io/providers/hashicorp/aws/6.0.0/docs/resources/route53_record) | resource |
 | [aws_route_table.public](https://registry.terraform.io/providers/hashicorp/aws/6.0.0/docs/resources/route_table) | resource |
 | [aws_route_table_association.public](https://registry.terraform.io/providers/hashicorp/aws/6.0.0/docs/resources/route_table_association) | resource |
-| [aws_security_group.allow_ssh](https://registry.terraform.io/providers/hashicorp/aws/6.0.0/docs/resources/security_group) | resource |
+| [aws_security_group.red_sg](https://registry.terraform.io/providers/hashicorp/aws/6.0.0/docs/resources/security_group) | resource |
 | [aws_subnet.public](https://registry.terraform.io/providers/hashicorp/aws/6.0.0/docs/resources/subnet) | resource |
 | [aws_vpc.main](https://registry.terraform.io/providers/hashicorp/aws/6.0.0/docs/resources/vpc) | resource |
 | [local_file.red_private_key_file](https://registry.terraform.io/providers/hashicorp/local/latest/docs/resources/file) | resource |
 | [tls_private_key.red_private_key](https://registry.terraform.io/providers/hashicorp/tls/latest/docs/resources/private_key) | resource |
 | [aws_ami.red_ami](https://registry.terraform.io/providers/hashicorp/aws/6.0.0/docs/data-sources/ami) | data source |
+| [aws_availability_zones.available](https://registry.terraform.io/providers/hashicorp/aws/6.0.0/docs/data-sources/availability_zones) | data source |
 | [aws_route53_zone.zone](https://registry.terraform.io/providers/hashicorp/aws/6.0.0/docs/data-sources/route53_zone) | data source |
 
 ## Inputs
@@ -79,7 +80,7 @@ No modules.
 |------|-------------|------|---------|:--------:|
 | <a name="input_additional_tags"></a> [additional\_tags](#input\_additional\_tags) | Additional tags to apply to the resources | `map(string)` | `{}` | no |
 | <a name="input_allocate_eip"></a> [allocate\_eip](#input\_allocate\_eip) | Controls whether an Elastic IP should be allocated | `bool` | `true` | no |
-| <a name="input_ami_name"></a> [ami\_name](#input\_ami\_name) | The name of the AMI to use for the instance | `string` | `"ubuntu/images/hvm-ssd-gp3/ubuntu-noble-24.04-arm64-server-20250305"` | no |
+| <a name="input_ami_name"></a> [ami\_name](#input\_ami\_name) | The name of the AMI to use for the instance | `string` | `"ubuntu/images/hvm-ssd-gp3/ubuntu-noble-24.04-arm64-server-20250610"` | no |
 | <a name="input_ami_owner"></a> [ami\_owner](#input\_ami\_owner) | The owner of the AMI to use for the instance | `string` | `"099720109477"` | no |
 | <a name="input_apex_domain"></a> [apex\_domain](#input\_apex\_domain) | The apex domain to use for the public DNS record | `string` | `""` | no |
 | <a name="input_create_ec2_key_pair"></a> [create\_ec2\_key\_pair](#input\_create\_ec2\_key\_pair) | Controls whether an EC2 key pair should be created | `bool` | `false` | no |

red-instance/main.tf

@@ -15,7 +15,7 @@ provider "aws" {
 
 # Data source to get the Red Instance AMI
 data "aws_ami" "red_ami" {
-  most_recent = true
+  most_recent        = true
   include_deprecated = true
 
   filter {

red-instance/public_vpc.tf

@@ -1,5 +1,14 @@
 # This file creates a VPC, a public subnet, an internet gateway, a route table, and associates the route table with the subnet.
 
+# Data source to get available AZs that support the instance type
+data "aws_availability_zones" "available" {
+  count = var.create_vpc ? 1 : 0
+  state = "available"
+
+  # Filter to exclude AZs that typically don't support ARM instances
+  exclude_names = ["us-east-1e"] # Add other problematic AZs as needed
+}
+
 # The resources are created conditionally based on the value of the create_vpc variable.
 # Justification: This is for development purposes, Flow Logs and other features are not required for a red instance.
 # trivy:ignore:AVD-AWS-0178
@@ -18,7 +27,7 @@ resource "aws_vpc" "main" {
   )
 }
 
-# Create a public subnet
+# Create a public subnet with explicit AZ
 # Justification: This is a public subnet for the red instance
 # trivy:ignore:AVD-AWS-0164
 resource "aws_subnet" "public" {
@@ -27,6 +36,9 @@ resource "aws_subnet" "public" {
   cidr_block              = "10.0.1.0/24"
   map_public_ip_on_launch = true
 
+  # Use the first available AZ that supports ARM instances
+  availability_zone = data.aws_availability_zones.available[0].names[0]
+
   tags = merge(
     {
       Name    = "${lower(var.instance_name)}-red-instance-public-subnet"