Migrate Azure module Terraform v0.11 to v0.12

* Replace v0.11 bracket type hints with Terraform v0.12 list expressions
* Use expression syntax instead of interpolated strings, where suggested
* Update Azure tutorial and worker pools documentation
* Define Terraform and plugin version requirements in versions.tf
  * Require azurerm ~> 1.27 to support Terraform v0.12
  * Require ct ~> 0.3.2 to support Terraform v0.12

azure/container-linux/kubernetes/workers/variables.tf

@@ -1,63 +1,63 @@
 variable "name" {
-  type        = "string"
+  type        = string
   description = "Unique name for the worker pool"
 }
 
 # Azure
 
 variable "region" {
-  type        = "string"
+  type        = string
   description = "Must be set to the Azure Region of cluster"
 }
 
 variable "resource_group_name" {
-  type        = "string"
+  type        = string
   description = "Must be set to the resource group name of cluster"
 }
 
 variable "subnet_id" {
-  type        = "string"
+  type        = string
   description = "Must be set to the `worker_subnet_id` output by cluster"
 }
 
 variable "security_group_id" {
-  type        = "string"
+  type        = string
   description = "Must be set to the `worker_security_group_id` output by cluster"
 }
 
 variable "backend_address_pool_id" {
-  type        = "string"
+  type        = string
   description = "Must be set to the `worker_backend_address_pool_id` output by cluster"
 }
 
 # instances
 
 variable "worker_count" {
-  type        = "string"
+  type        = string
   default     = "1"
   description = "Number of instances"
 }
 
 variable "vm_type" {
-  type        = "string"
+  type        = string
   default     = "Standard_F1"
   description = "Machine type for instances (see `az vm list-skus --location centralus`)"
 }
 
 variable "os_image" {
-  type        = "string"
+  type        = string
   default     = "coreos-stable"
   description = "Channel for a Container Linux derivative (coreos-stable, coreos-beta, coreos-alpha)"
 }
 
 variable "priority" {
-  type        = "string"
+  type        = string
   default     = "Regular"
   description = "Set priority to Low to use reduced cost surplus capacity, with the tradeoff that instances can be evicted at any time."
 }
 
 variable "clc_snippets" {
-  type        = "list"
+  type        = list(string)
   description = "Container Linux Config snippets"
   default     = []
 }
@@ -65,12 +65,12 @@ variable "clc_snippets" {
 # configuration
 
 variable "kubeconfig" {
-  type        = "string"
+  type        = string
   description = "Must be set to `kubeconfig` output by cluster"
 }
 
 variable "ssh_authorized_key" {
-  type        = "string"
+  type        = string
   description = "SSH public key for user 'core'"
 }
 
@@ -80,12 +80,14 @@ CIDR IPv4 range to assign Kubernetes services.
 The 1st IP will be reserved for kube_apiserver, the 10th IP will be reserved for coredns.
 EOD
 
-  type    = "string"
+
+  type = string
   default = "10.3.0.0/16"
 }
 
 variable "cluster_domain_suffix" {
   description = "Queries for domains with the suffix will be answered by coredns. Default is cluster.local (e.g. foo.default.svc.cluster.local) "
-  type        = "string"
-  default     = "cluster.local"
+  type = string
+  default = "cluster.local"
 }
+

azure/container-linux/kubernetes/workers/versions.tf

@@ -0,0 +1,4 @@
+
+terraform {
+  required_version = ">= 0.12"
+}

azure/container-linux/kubernetes/workers/workers.tf

@@ -1,28 +1,28 @@
 locals {
   # Channel for a Container Linux derivative
   # coreos-stable -> Container Linux Stable
-  channel = "${element(split("-", var.os_image), 1)}"
+  channel = element(split("-", var.os_image), 1)
 }
 
 # Workers scale set
 resource "azurerm_virtual_machine_scale_set" "workers" {
-  resource_group_name = "${var.resource_group_name}"
+  resource_group_name = var.resource_group_name
 
   name                   = "${var.name}-workers"
-  location               = "${var.region}"
+  location               = var.region
   single_placement_group = false
 
   sku {
-    name     = "${var.vm_type}"
+    name     = var.vm_type
     tier     = "standard"
-    capacity = "${var.worker_count}"
+    capacity = var.worker_count
   }
 
   # boot
   storage_profile_image_reference {
     publisher = "CoreOS"
     offer     = "CoreOS"
-    sku       = "${local.channel}"
+    sku       = local.channel
     version   = "latest"
   }
 
@@ -37,7 +37,7 @@ resource "azurerm_virtual_machine_scale_set" "workers" {
   os_profile {
     computer_name_prefix = "${var.name}-worker-"
     admin_username       = "core"
-    custom_data          = "${data.ct_config.worker-ignition.rendered}"
+    custom_data          = data.ct_config.worker-ignition.rendered
   }
 
   # Azure mandates setting an ssh_key, even though Ignition custom_data handles it too
@@ -46,7 +46,7 @@ resource "azurerm_virtual_machine_scale_set" "workers" {
 
     ssh_keys {
       path     = "/home/core/.ssh/authorized_keys"
-      key_data = "${var.ssh_authorized_key}"
+      key_data = var.ssh_authorized_key
     }
   }
 
@@ -54,61 +54,62 @@ resource "azurerm_virtual_machine_scale_set" "workers" {
   network_profile {
     name                      = "nic0"
     primary                   = true
-    network_security_group_id = "${var.security_group_id}"
+    network_security_group_id = var.security_group_id
 
     ip_configuration {
       name      = "ip0"
       primary   = true
-      subnet_id = "${var.subnet_id}"
+      subnet_id = var.subnet_id
 
       # backend address pool to which the NIC should be added
-      load_balancer_backend_address_pool_ids = ["${var.backend_address_pool_id}"]
+      load_balancer_backend_address_pool_ids = [var.backend_address_pool_id]
     }
   }
 
   # lifecycle
   upgrade_policy_mode = "Manual"
-  priority            = "${var.priority}"
+  priority            = var.priority
   eviction_policy     = "Delete"
 }
 
 # Scale up or down to maintain desired number, tolerating deallocations.
 resource "azurerm_monitor_autoscale_setting" "workers" {
-  resource_group_name = "${var.resource_group_name}"
+  resource_group_name = var.resource_group_name
 
   name     = "${var.name}-maintain-desired"
-  location = "${var.region}"
+  location = var.region
 
   # autoscale
   enabled            = true
-  target_resource_id = "${azurerm_virtual_machine_scale_set.workers.id}"
+  target_resource_id = azurerm_virtual_machine_scale_set.workers.id
 
   profile {
     name = "default"
 
     capacity {
-      minimum = "${var.worker_count}"
-      default = "${var.worker_count}"
-      maximum = "${var.worker_count}"
+      minimum = var.worker_count
+      default = var.worker_count
+      maximum = var.worker_count
     }
   }
 }
 
 # Worker Ignition configs
 data "ct_config" "worker-ignition" {
-  content      = "${data.template_file.worker-config.rendered}"
+  content      = data.template_file.worker-config.rendered
   pretty_print = false
-  snippets     = ["${var.clc_snippets}"]
+  snippets     = var.clc_snippets
 }
 
 # Worker Container Linux configs
 data "template_file" "worker-config" {
-  template = "${file("${path.module}/cl/worker.yaml.tmpl")}"
+  template = file("${path.module}/cl/worker.yaml.tmpl")
 
   vars = {
-    kubeconfig             = "${indent(10, var.kubeconfig)}"
-    ssh_authorized_key     = "${var.ssh_authorized_key}"
-    cluster_dns_service_ip = "${cidrhost(var.service_cidr, 10)}"
-    cluster_domain_suffix  = "${var.cluster_domain_suffix}"
+    kubeconfig             = indent(10, var.kubeconfig)
+    ssh_authorized_key     = var.ssh_authorized_key
+    cluster_dns_service_ip = cidrhost(var.service_cidr, 10)
+    cluster_domain_suffix  = var.cluster_domain_suffix
   }
 }
+