feat: Propagate ami_type to self-managed node group; allow using ami_type only (#3030)

docs/compute_resources.md

@@ -31,7 +31,6 @@ Refer to the [EKS Managed Node Group documentation](https://docs.aws.amazon.com/
       use_custom_launch_template = false
 
       ami_type = "BOTTLEROCKET_x86_64"
-      platform = "bottlerocket"
     }
   }
 ```
@@ -42,7 +41,6 @@ Refer to the [EKS Managed Node Group documentation](https://docs.aws.amazon.com/
   eks_managed_node_groups = {
     bottlerocket_prepend_userdata = {
       ami_type = "BOTTLEROCKET_x86_64"
-      platform = "bottlerocket"
 
       bootstrap_extra_args = <<-EOT
         # extra args added
@@ -84,7 +82,7 @@ Refer to the [EKS Managed Node Group documentation](https://docs.aws.amazon.com/
   eks_managed_node_groups = {
     bottlerocket_custom_ami = {
       ami_id   = "ami-0ff61e0bcfc81dc94"
-      platform = "bottlerocket"
+      ami_type = "BOTTLEROCKET_x86_64"
 
       # use module user data template to bootstrap
       enable_bootstrap_user_data = true
@@ -123,15 +121,15 @@ Refer to the [Self Managed Node Group documentation](https://docs.aws.amazon.com
   }
 ```
 
-2. To use Bottlerocket, specify the `platform` as `bottlerocket` and supply a Bottlerocket OS AMI:
+2. To use Bottlerocket, specify the `ami_type` as one of the respective `"BOTTLEROCKET_*" types` and supply a Bottlerocket OS AMI:
 
 ```hcl
   cluster_version = "1.27"
 
   self_managed_node_groups = {
     bottlerocket = {
-      platform = "bottlerocket"
       ami_id   = data.aws_ami.bottlerocket_ami.id
+      ami_type = "BOTTLEROCKET_x86_64"
     }
   }
 ```
@@ -177,7 +175,6 @@ For example, the following creates 4 AWS EKS Managed Node Groups:
     # This overrides the OS used
     bottlerocket = {
       ami_type = "BOTTLEROCKET_x86_64"
-      platform = "bottlerocket"
     }
   }
 ```