diff --git a/README.md b/README.md
index f81e046..a397f8e 100644
--- a/README.md
+++ b/README.md
@@ -222,12 +222,11 @@ map(object({
   orchestrator\_version = (Required) The version of Kubernetes which should be used for this Node Pool. Changing this forces a new resource to be created.  
   max\_count            = (Optional) The maximum number of nodes which should exist within this Node Pool. Valid values are between `0` and `1000` and must be greater than or equal to `min_count`.  
   min\_count            = (Optional) The minimum number of nodes which should exist within this Node Pool. Valid values are between `0` and `1000` and must be less than or equal to `max_count`.  
-  os\_sku               = (Optional) Specifies the OS SKU used by the agent pool. Possible values include: `Ubuntu`, `CBLMariner`, `Mariner`, `Windows2019`, `Windows2022`. If not specified, the default is `Ubuntu` if OSType=Linux or `Windows2019` if OSType=Windows. And the default Windows OSSKU will be changed to `Windows2022` after Windows2019 is deprecated. Changing this forces a new resource to be created.  
+  os\_sku               = (Optional) Specifies the OS SKU used by the agent pool. Possible values include: `Ubuntu`or `AzureLinux`. If not specified, the default is `AzureLinux`. Changing this forces a new resource to be created.  
   mode                 = (Optional) Should this Node Pool be used for System or User resources? Possible values are `System` and `User`. Defaults to `User`.  
   os\_disk\_size\_gb      = (Optional) The Agent Operating System disk size in GB. Changing this forces a new resource to be created.  
   tags                 = (Optional) A mapping of tags to assign to the resource. At this time there's a bug in the AKS API where Tags for a Node Pool are not stored in the correct case - you [may wish to use Terraform's `ignore_changes` functionality to ignore changes to the casing](https://www.terraform.io/language/meta-arguments/lifecycle#ignore_changess) until this is fixed in the AKS API.  
-  labels               = (Optional) A map of Kubernetes labels which should be applied to nodes in this Node Pool.  
-  zones                = (Optional) Specifies a list of Availability Zones in which this Kubernetes Cluster Node Pool should be located. Changing this forces a new Kubernetes Cluster Node Pool to be created.
+  labels               = (Optional) A map of Kubernetes labels which should be applied to nodes in this Node Pool.
 }))
 
 Example input:
@@ -264,12 +263,11 @@ map(object({
     # do not add nodecount because we enforce the use of auto-scaling
     max_count       = optional(number)
     min_count       = optional(number)
-    os_sku          = optional(string)
+    os_sku          = optional(string, "AzureLinux")
     mode            = optional(string)
     os_disk_size_gb = optional(number, null)
     tags            = optional(map(string), {})
     labels          = optional(map(string), {})
-    zones           = optional(set(string))
   }))
 ```
 
@@ -283,6 +281,14 @@ Type: `string`
 
 Default: `null`
 
+### <a name="input_os_sku"></a> [os\_sku](#input\_os\_sku)
+
+Description: (Optional) Specifies the OS SKU used by the agent pool. Possible values include: `Ubuntu` or `AzureLinux`. If not specified, the default is `AzureLinux`.Changing this forces a new resource to be created.
+
+Type: `string`
+
+Default: `"AzureLinux"`
+
 ### <a name="input_rbac_aad_admin_group_object_ids"></a> [rbac\_aad\_admin\_group\_object\_ids](#input\_rbac\_aad\_admin\_group\_object\_ids)
 
 Description: Object ID of groups with admin access.
diff --git a/examples/without_availability_zone/README.md b/examples/without_availability_zone/README.md
index ae05d72..554e763 100644
--- a/examples/without_availability_zone/README.md
+++ b/examples/without_availability_zone/README.md
@@ -75,7 +75,7 @@ module "test" {
       orchestrator_version = "1.28"
       max_count            = 110
       min_count            = 2
-      os_sku               = "Ubuntu"
+      os_sku               = "AzureLinux"
       mode                 = "User"
     },
     ingress = {
@@ -84,7 +84,7 @@ module "test" {
       orchestrator_version = "1.28"
       max_count            = 4
       min_count            = 2
-      os_sku               = "Ubuntu"
+      os_sku               = "AzureLinux"
       mode                 = "User"
     }
   }
diff --git a/examples/without_availability_zone/main.tf b/examples/without_availability_zone/main.tf
index b461e89..f1b6832 100644
--- a/examples/without_availability_zone/main.tf
+++ b/examples/without_availability_zone/main.tf
@@ -69,7 +69,7 @@ module "test" {
       orchestrator_version = "1.28"
       max_count            = 110
       min_count            = 2
-      os_sku               = "Ubuntu"
+      os_sku               = "AzureLinux"
       mode                 = "User"
     },
     ingress = {
@@ -78,7 +78,7 @@ module "test" {
       orchestrator_version = "1.28"
       max_count            = 4
       min_count            = 2
-      os_sku               = "Ubuntu"
+      os_sku               = "AzureLinux"
       mode                 = "User"
     }
   }
diff --git a/main.tf b/main.tf
index 7cd5703..420e07a 100644
--- a/main.tf
+++ b/main.tf
@@ -75,7 +75,7 @@ resource "azurerm_kubernetes_cluster" "this" {
     min_count              = 3
     node_labels            = var.node_labels
     orchestrator_version   = var.orchestrator_version
-    os_sku                 = "Ubuntu"
+    os_sku                 = var.os_sku
     tags                   = merge(var.tags, var.agents_tags)
     vnet_subnet_id         = var.network.node_subnet_id
     zones                  = try([for zone in local.regions_by_name_or_display_name[var.location].zones : zone], null)
diff --git a/variables.tf b/variables.tf
index ed01695..87d3cc7 100644
--- a/variables.tf
+++ b/variables.tf
@@ -128,12 +128,11 @@ variable "node_pools" {
     # do not add nodecount because we enforce the use of auto-scaling
     max_count       = optional(number)
     min_count       = optional(number)
-    os_sku          = optional(string)
+    os_sku          = optional(string, "AzureLinux")
     mode            = optional(string)
     os_disk_size_gb = optional(number, null)
     tags            = optional(map(string), {})
     labels          = optional(map(string), {})
-    zones           = optional(set(string))
   }))
   default     = {}
   description = <<-EOT
@@ -144,12 +143,11 @@ map(object({
   orchestrator_version = (Required) The version of Kubernetes which should be used for this Node Pool. Changing this forces a new resource to be created.
   max_count            = (Optional) The maximum number of nodes which should exist within this Node Pool. Valid values are between `0` and `1000` and must be greater than or equal to `min_count`.
   min_count            = (Optional) The minimum number of nodes which should exist within this Node Pool. Valid values are between `0` and `1000` and must be less than or equal to `max_count`.
-  os_sku               = (Optional) Specifies the OS SKU used by the agent pool. Possible values include: `Ubuntu`, `CBLMariner`, `Mariner`, `Windows2019`, `Windows2022`. If not specified, the default is `Ubuntu` if OSType=Linux or `Windows2019` if OSType=Windows. And the default Windows OSSKU will be changed to `Windows2022` after Windows2019 is deprecated. Changing this forces a new resource to be created.
+  os_sku               = (Optional) Specifies the OS SKU used by the agent pool. Possible values include: `Ubuntu`or `AzureLinux`. If not specified, the default is `AzureLinux`. Changing this forces a new resource to be created.
   mode                 = (Optional) Should this Node Pool be used for System or User resources? Possible values are `System` and `User`. Defaults to `User`.
   os_disk_size_gb      = (Optional) The Agent Operating System disk size in GB. Changing this forces a new resource to be created.
   tags                 = (Optional) A mapping of tags to assign to the resource. At this time there's a bug in the AKS API where Tags for a Node Pool are not stored in the correct case - you [may wish to use Terraform's `ignore_changes` functionality to ignore changes to the casing](https://www.terraform.io/language/meta-arguments/lifecycle#ignore_changess) until this is fixed in the AKS API.
   labels               = (Optional) A map of Kubernetes labels which should be applied to nodes in this Node Pool.
-  zones                = (Optional) Specifies a list of Availability Zones in which this Kubernetes Cluster Node Pool should be located. Changing this forces a new Kubernetes Cluster Node Pool to be created.
 }))
 
 Example input:
@@ -177,6 +175,11 @@ Example input:
   ```
 EOT
   nullable    = false
+
+  validation {
+    condition     = alltrue([for pool in var.node_pools : contains(["Ubuntu", "AzureLinux"], pool.os_sku)])
+    error_message = "os_sku must be either Ubuntu or AzureLinux"
+  }
 }
 
 variable "orchestrator_version" {
@@ -185,6 +188,17 @@ variable "orchestrator_version" {
   description = "Specify which Kubernetes release to use. Specify only minor version, such as '1.28'."
 }
 
+variable "os_sku" {
+  type        = string
+  default     = "AzureLinux"
+  description = "(Optional) Specifies the OS SKU used by the agent pool. Possible values include: `Ubuntu` or `AzureLinux`. If not specified, the default is `AzureLinux`.Changing this forces a new resource to be created."
+
+  validation {
+    condition     = can(regex("^(Ubuntu|AzureLinux)$", var.os_sku))
+    error_message = "os_sku must be either Ubuntu or AzureLinux"
+  }
+}
+
 variable "rbac_aad_admin_group_object_ids" {
   type        = list(string)
   default     = null