chore(privatek8s): change from ubuntu to azure linux the os for the n…

…odes (#662)

as per
https://learn.microsoft.com/en-us/azure/azure-linux/intro-azure-linux#azure-linux-container-host-key-benefits
AzureLinux OS is lighter and more prone to fast security update.

Lets take advantage to those 2 not yet used nodepool to switch from
ubuntu to azurelinux

privatek8s.tf

@@ -186,6 +186,7 @@ resource "azurerm_kubernetes_cluster_node_pool" "infraciarm64" {
 resource "azurerm_kubernetes_cluster_node_pool" "infraci_controller" {
   name                  = "infracictrl"
   vm_size               = "Standard_D4pds_v5" # 4 vCPU, 16 GB RAM, local disk: 150 GB and 19000 IOPS
+  os_sku                = "AzureLinux"
   os_disk_type          = "Ephemeral"
   os_disk_size_gb       = 150 # Ref. Cache storage size at https://learn.microsoft.com/en-us/azure/virtual-machines/dpsv5-dpdsv5-series#dpdsv5-series (depends on the instance size)
   orchestrator_version  = local.kubernetes_versions["privatek8s"]
@@ -211,6 +212,7 @@ resource "azurerm_kubernetes_cluster_node_pool" "infraci_controller" {
 resource "azurerm_kubernetes_cluster_node_pool" "releaseci_controller" {
   name                  = "releacictrl"
   vm_size               = "Standard_D4pds_v5" # 4 vCPU, 16 GB RAM, local disk: 150 GB and 19000 IOPS
+  os_sku                = "AzureLinux"
   os_disk_type          = "Ephemeral"
   os_disk_size_gb       = 150 # Ref. Cache storage size at https://learn.microsoft.com/en-us/azure/virtual-machines/dpsv5-dpdsv5-series#dpdsv5-series (depends on the instance size)
   orchestrator_version  = local.kubernetes_versions["privatek8s"]