169163334 - Adds autoscaling to k8s

This adds node autoscaling the k8s. Pod autoscaling needs to be
configured in the kubectl config.

terraform/modules/k8s/main.tf

@@ -21,6 +21,9 @@ resource "azurerm_kubernetes_cluster" "k8s" {
     vnet_subnet_id        = var.vnet_subnet_id
     node_count            = 1
     enable_node_public_ip = true # Nodes need a public IP for external resources. FIXME: Switch to NAT Gateway if its available in our subscription
+    enable_auto_scaling   = var.enable_auto_scaling
+    max_count             = var.max_count # FIXME: if auto_scaling disabled, set to 0
+    min_count             = var.min_count # FIXME: if auto_scaling disabled, set to 0
   }
 
   lifecycle {

terraform/modules/k8s/variables.tf

@@ -33,3 +33,22 @@ variable "vnet_subnet_id" {
   description = "Subnet to use for the default k8s pool"
   type        = string
 }
+
+variable "enable_auto_scaling" {
+  default     = false
+  type        = string
+  description = "Enable or disable autoscaling (Default: false)"
+}
+
+variable "max_count" {
+  default     = 1
+  type        = string
+  description = "Maximum number of nodes to use in autoscaling. This requires `enable_auto_scaling` to be set to true"
+
+}
+
+variable "min_count" {
+  default     = 1
+  type        = string
+  description = "Minimum number of nodes to use in autoscaling. This requires `enable_auto_scaling` to be set to true"
+}

terraform/providers/dev/k8s.tf

@@ -7,6 +7,9 @@ module "k8s" {
   k8s_dns_prefix     = var.k8s_dns_prefix
   k8s_node_size      = var.k8s_node_size
   vnet_subnet_id     = module.vpc.subnets #FIXME - output from module.vpc.subnets should be map
+  enable_auto_scaling = true
+  max_count          = 5
+  min_count          = 2
 }
 
 #module "main_lb" {