feat: support user to specify AMI for node gorup

examples/aws-project-byoc-I/data.tf

@@ -68,8 +68,12 @@ locals {
   }
 
   # Kubernetes node group specifications and resource quotas
-  # Defines the compute capacity and node types for the EKS cluster
-  k8s_node_groups = data.zillizcloud_byoc_i_project_settings.this.node_quotas
+  # Merges node quotas from Zilliz cloud settings with optional ami_type overrides
+  k8s_node_groups = {
+    for name, ng in data.zillizcloud_byoc_i_project_settings.this.node_quotas : name => merge(ng, {
+      ami_type = lookup(var.k8s_node_group_ami_type, name, "")
+    })
+  }
 
   # Zilliz project identifier for resource tagging and organization
   # Links AWS resources back to the specific Zilliz cloud project

examples/aws-project-byoc-I/terraform.sample.tfvars

@@ -107,6 +107,17 @@ minimal_roles = {
   }
 }
 
+# Optional AMI type override per node group (core, index, search, fundamental)
+# By default, AMI type is auto-detected from instance architecture:
+#   - ARM instances (e.g., m6g, c7g, t4g) -> AL2023_ARM_64_STANDARD
+#   - x86 instances (e.g., m6i, c5, r5)   -> AL2023_x86_64_STANDARD
+# k8s_node_group_ami_type = {
+#   fundamental = "BOTTLEROCKET_x86_64"
+#   search      = "BOTTLEROCKET_x86_64"
+#   index       = "BOTTLEROCKET_x86_64"
+#   core        = "BOTTLEROCKET_x86_64"
+# }
+
 # Enable AWS Client-Side Encryption (CSE) for Milvus data
 # When enabled without aws_cse_exiting_key_arn, a new KMS key will be created automatically
 enable_aws_cse          = false

examples/aws-project-byoc-I/variables.tf

@@ -221,4 +221,31 @@ variable "aws_cse_exiting_key_arn" {
   description = "The ARN of the existing KMS key to use for AWS CSE"
   type        = string
   default     = ""
+}
+
+variable "k8s_node_group_ami_type" {
+  description = <<-EOT
+    Optional AMI type override per node group (core, index, search, fundamental).
+    By default, the AMI type is auto-detected based on instance architecture:
+      - ARM instances (e.g., m6g, c7g, t4g) -> AL2023_ARM_64_STANDARD
+      - x86 instances (e.g., m6i, c5, r5)   -> AL2023_x86_64_STANDARD
+
+    When specified, the provided value takes precedence over auto-detection.
+    Only the node groups listed in the map are overridden; others keep auto-detection.
+
+    Example - override a single node group:
+      k8s_node_group_ami_type = {
+        core = "AL2_x86_64"
+      }
+
+    Example - override multiple node groups:
+      k8s_node_group_ami_type = {
+        fundamental   = "BOTTLEROCKET_x86_64"
+        search        = "BOTTLEROCKET_x86_64"
+        index         = "BOTTLEROCKET_x86_64"
+        core          = "BOTTLEROCKET_x86_64"
+      }
+  EOT
+  type        = map(string)
+  default     = {}
 }

modules/aws_byoc_i/eks/eks_nodegroup.tf

@@ -239,16 +239,16 @@ resource "aws_launch_template" "diskann" {
 }
 
 
-# Determine AMI type based on instance architecture
+# Determine AMI type for each node group:
+# - Use the explicitly provided ami_type if set
+# - Otherwise auto-detect from instance type (ARM 'g' suffix -> AL2023_ARM_64_STANDARD, else AL2023_x86_64_STANDARD)
 locals {
-  # Map instance types to their appropriate AMI types
-  # ARM instances typically have 'g' in their generation identifier (e.g., m6g, c7g, t4g)
-  # This regex matches instance types with 'g' after the number, which indicates ARM architecture
   ami_types = {
-    search      = can(regex("^[a-z]+[0-9]+g[a-z]*\\.", var.k8s_node_groups.search.instance_types)) ? "AL2023_ARM_64_STANDARD" : "AL2023_x86_64_STANDARD"
-    core        = can(regex("^[a-z]+[0-9]+g[a-z]*\\.", var.k8s_node_groups.core.instance_types)) ? "AL2023_ARM_64_STANDARD" : "AL2023_x86_64_STANDARD"
-    index       = can(regex("^[a-z]+[0-9]+g[a-z]*\\.", var.k8s_node_groups.index.instance_types)) ? "AL2023_ARM_64_STANDARD" : "AL2023_x86_64_STANDARD"
-    fundamental = can(regex("^[a-z]+[0-9]+g[a-z]*\\.", var.k8s_node_groups.fundamental.instance_types)) ? "AL2023_ARM_64_STANDARD" : "AL2023_x86_64_STANDARD"
+    for name, ng in var.k8s_node_groups : name => (
+      ng.ami_type != "" ? ng.ami_type : (
+        can(regex("^[a-z]+[0-9]+g[a-z]*\\.", ng.instance_types)) ? "AL2023_ARM_64_STANDARD" : "AL2023_x86_64_STANDARD"
+      )
+    )
   }
 }
 
@@ -453,7 +453,8 @@ resource "time_sleep" "wait_init" {
 }
 
 resource "aws_eks_node_group" "init" {
-  ami_type      = "AL2023_x86_64_STANDARD"
+  # make it share the same AMI type as core node group
+  ami_type      = local.ami_types.core
   capacity_type = "ON_DEMAND"
   cluster_name  = local.eks_cluster_name
 

modules/aws_byoc_i/eks/variables.tf

@@ -85,6 +85,7 @@ variable "k8s_node_groups" {
     desired_size   = number
     instance_types = string
     capacity_type  = string
+    ami_type       = optional(string, "")
   }))
 
   default = {