Configure controller and worker node architecture separately

* On platforms that support ARM64 instances, configure controller
and worker node host architectures separately
* For example, you can run arm64 controllers and amd64 workers
* Add `controller_arch` and `worker_arch` variables
* Remove `arch` variable

aws/fedora-coreos/kubernetes/ami.tf

@@ -19,7 +19,7 @@ data "aws_ami" "fedora-coreos" {
 }
 
 data "aws_ami" "fedora-coreos-arm" {
-  count = var.arch == "arm64" ? 1 : 0
+  count = var.controller_arch == "arm64" ? 1 : 0
 
   most_recent = true
   owners      = ["125523088429"]

aws/fedora-coreos/kubernetes/controllers.tf

@@ -22,7 +22,7 @@ resource "aws_instance" "controllers" {
   }
 
   instance_type = var.controller_type
-  ami           = var.arch == "arm64" ? data.aws_ami.fedora-coreos-arm[0].image_id : data.aws_ami.fedora-coreos.image_id
+  ami           = var.controller_arch == "arm64" ? data.aws_ami.fedora-coreos-arm[0].image_id : data.aws_ami.fedora-coreos.image_id
   user_data     = data.ct_config.controllers.*.rendered[count.index]
 
   # storage

aws/fedora-coreos/kubernetes/variables.tf

@@ -190,14 +190,25 @@ variable "cluster_domain_suffix" {
   default     = "cluster.local"
 }
 
-variable "arch" {
-  type        = string
-  description = "Container architecture (amd64 or arm64)"
-  default     = "amd64"
+# advanced
 
+variable "controller_arch" {
+  type        = string
+  description = "Controller node(s) architecture (amd64 or arm64)"
+  default     = "amd64"
   validation {
-    condition     = var.arch == "amd64" || var.arch == "arm64"
-    error_message = "The arch must be amd64 or arm64."
+    condition     = contains(["amd64", "arm64"], var.controller_arch)
+    error_message = "The controller_arch must be amd64 or arm64."
+  }
+}
+
+variable "worker_arch" {
+  type        = string
+  description = "Worker node(s) architecture (amd64 or arm64)"
+  default     = "amd64"
+  validation {
+    condition     = contains(["amd64", "arm64"], var.worker_arch)
+    error_message = "The worker_arch must be amd64 or arm64."
   }
 }
 

aws/fedora-coreos/kubernetes/workers.tf

@@ -9,7 +9,7 @@ module "workers" {
   worker_count    = var.worker_count
   instance_type   = var.worker_type
   os_stream       = var.os_stream
-  arch            = var.arch
+  arch            = var.worker_arch
   disk_type       = var.worker_disk_type
   disk_size       = var.worker_disk_size
   disk_iops       = var.worker_disk_iops