diff --git a/.circleci/config.yml b/.circleci/config.yml
index f8378c2..c27d00f 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -5,10 +5,10 @@ jobs:
     working_directory: ~/repo
 
     docker:
-      - image: unifio/ci:3.0.622-ruby-2.5.3
+      - image: unifio/ci:5.0.945-ruby-2.5.5
 
     environment:
-      AWS_REGION: 'us-east-2'
+      AWS_REGION: 'us-east-1'
       CI_REPORTS: 'reports/infrastructure'
       TF_PLUGIN_CACHE_DIR: "/root/.terraform.d/plugin-cache"
 
diff --git a/.env.docker b/.env.docker
index cfa2e93..2076db9 100644
--- a/.env.docker
+++ b/.env.docker
@@ -1,4 +1,7 @@
-AWS_REGION=us-east-2
+AWS_REGION=us-east-1
+AWS_PROFILE=unifiouat
+AWS_DEFAULT_PROFILE=unifiouat
+AWS_DEFAULT_REGION=us-east-1
 COVALENCE_LOG=info
 COVALENCE_TEST_ENVS=basic,complete
 CHECKPOINT_DISABLE=1
diff --git a/CHANGELOG.md b/CHANGELOG.md
index a9e1285..2f74e18 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,14 @@
 #### IMPROVEMENTS / NEW FEATURES:
 * Add support for application auto scaling
 
+## 0.4.0 (May 28, 2020)
+
+#### IMPROVEMENTS / NEW FEATURES:
+* Updated for Terraform v0.12
+
+#### BACKWARDS INCOMPATIBILITIES / NOTES:
+* Terraform versions earlier than 0.12.0 no longer supported.
+
 ## 0.3.3 (March 10, 2019)
 
 #### BACKWARDS INCOMPATIBILITIES / NOTES:
diff --git a/README.md b/README.md
index e4a4264..3b25fc1 100644
--- a/README.md
+++ b/README.md
@@ -5,7 +5,7 @@ Terraform module for the deployment of an AWS Elastic Container Service (ECS) cl
 
 ## Requirements ##
 
-- Terraform 0.11.0 or newer
+- Terraform 0.12.0 or newer
 - AWS provider
 
 ## Cluster module ##
diff --git a/cluster/iam.tf b/cluster/iam.tf
index 95e50c2..46782ff 100644
--- a/cluster/iam.tf
+++ b/cluster/iam.tf
@@ -14,15 +14,15 @@ data "aws_iam_policy_document" "agent_policy" {
 }
 
 resource "aws_iam_role" "agent_role" {
-  assume_role_policy = "${data.aws_iam_policy_document.agent_policy.json}"
+  assume_role_policy = data.aws_iam_policy_document.agent_policy.json
   name               = "ecs-agent-${var.cluster_label}-${var.stack_item_label}-${data.aws_region.current.name}"
-  path               = "${var.iam_path}"
+  path               = var.iam_path
 }
 
 resource "aws_iam_instance_profile" "agent_profile" {
   name = "ecs-agent-${var.cluster_label}-${var.stack_item_label}-${data.aws_region.current.name}"
-  path = "${var.iam_path}"
-  role = "${aws_iam_role.agent_role.name}"
+  path = var.iam_path
+  role = aws_iam_role.agent_role.name
 }
 
 ### Creates monitoring policy
@@ -40,8 +40,8 @@ data "aws_iam_policy_document" "monitoring_policy" {
 
 resource "aws_iam_role_policy" "monitoring_policy" {
   name   = "monitoring"
-  policy = "${data.aws_iam_policy_document.monitoring_policy.json}"
-  role   = "${aws_iam_role.agent_role.id}"
+  policy = data.aws_iam_policy_document.monitoring_policy.json
+  role   = aws_iam_role.agent_role.id
 }
 
 ### Creates resource tagging policy
@@ -55,8 +55,8 @@ data "aws_iam_policy_document" "tagging_policy" {
 
 resource "aws_iam_role_policy" "tagging_policy" {
   name   = "tagging"
-  policy = "${data.aws_iam_policy_document.tagging_policy.json}"
-  role   = "${aws_iam_role.agent_role.id}"
+  policy = data.aws_iam_policy_document.tagging_policy.json
+  role   = aws_iam_role.agent_role.id
 }
 
 ### Creates Elastic Container Service (ECS) service policy
@@ -80,13 +80,13 @@ data "aws_iam_policy_document" "ecs_policy" {
 
 resource "aws_iam_role_policy" "ecs_policy" {
   name   = "ecs"
-  policy = "${data.aws_iam_policy_document.ecs_policy.json}"
-  role   = "${aws_iam_role.agent_role.id}"
+  policy = data.aws_iam_policy_document.ecs_policy.json
+  role   = aws_iam_role.agent_role.id
 }
 
 ### Creates Simple Storage Service (S3) policy for logging buckets
 data "aws_iam_policy_document" "logging_policy" {
-  count = "${var.logs_bucket_enabled == "true" ? "1" : "0"}"
+  count = var.logs_bucket_enabled == "true" ? "1" : "0"
 
   statement {
     actions   = ["s3:ListBucket"]
@@ -106,9 +106,10 @@ data "aws_iam_policy_document" "logging_policy" {
 }
 
 resource "aws_iam_role_policy" "logging_policy" {
-  count = "${var.logs_bucket_enabled == "true" ? "1" : "0"}"
+  count = var.logs_bucket_enabled == "true" ? "1" : "0"
 
   name   = "logging"
-  policy = "${data.aws_iam_policy_document.logging_policy.json}"
-  role   = "${aws_iam_role.agent_role.id}"
+  policy = data.aws_iam_policy_document.logging_policy[0].json
+  role   = aws_iam_role.agent_role.id
 }
+
diff --git a/cluster/main.tf b/cluster/main.tf
index 1cabf20..31ecc05 100644
--- a/cluster/main.tf
+++ b/cluster/main.tf
@@ -1,19 +1,15 @@
 # Elastic Container Service (ECS) cluster
 
-## Set Terraform version constraint
-terraform {
-  required_version = "> 0.11.0"
+data "aws_region" "current" {
 }
 
-data "aws_region" "current" {}
-
 ## Creates cloud-config data for agent cluster
 data "template_file" "user_data" {
-  template = "${var.user_data_override != "" ? "" : file("${path.module}/templates/user_data.hcl")}"
+  template = var.user_data_override != "" ? "" : file("${path.module}/templates/user_data.hcl")
 
-  vars {
-    cluster_label    = "${var.cluster_label}"
-    stack_item_label = "${var.stack_item_label}"
+  vars = {
+    cluster_label    = var.cluster_label
+    stack_item_label = var.stack_item_label
   }
 }
 
@@ -44,58 +40,61 @@ data "aws_ami" "ecs_ami" {
 }
 
 module "cluster" {
-  source = "github.com/unifio/terraform-aws-asg?ref=v0.3.7//group"
+  source = "github.com/unifio/terraform-aws-asg?ref=upgrade-0.12//group"
 
   # Resource tags
-  stack_item_fullname = "${var.stack_item_fullname}"
+  stack_item_fullname = var.stack_item_fullname
   stack_item_label    = "${var.cluster_label}-${var.stack_item_label}"
 
   # VPC parameters
-  subnets = ["${var.subnets}"]
-  vpc_id  = "${var.vpc_id}"
+  subnets = var.subnets
+  vpc_id  = var.vpc_id
 
   # LC parameters
-  ami                           = "${coalesce(var.ami_override,data.aws_ami.ecs_ami.id)}"
-  associate_public_ip_address   = "${var.associate_public_ip_address}"
-  ebs_optimized                 = "${var.ebs_optimized}"
-  ebs_vol_del_on_term           = "${var.ebs_vol_del_on_term}"
-  ebs_vol_device_name           = "${var.ebs_vol_device_name}"
-  ebs_vol_encrypted             = "${var.ebs_vol_encrypted}"
-  ebs_vol_iops                  = "${var.ebs_vol_iops}"
-  ebs_vol_size                  = "${var.ebs_vol_size}"
-  ebs_vol_snapshot_id           = "${var.ebs_vol_snapshot_id}"
-  ebs_vol_type                  = "${var.ebs_vol_type}"
-  enable_monitoring             = "${var.enable_monitoring}"
-  instance_based_naming_enabled = "${var.instance_based_naming_enabled}"
-  instance_name_prefix          = "${var.instance_name_prefix}"
-  instance_profile              = "${aws_iam_instance_profile.agent_profile.id}"
-  instance_tags                 = "${var.instance_tags}"
-  instance_type                 = "${var.instance_type}"
-  key_name                      = "${var.key_name}"
-  placement_tenancy             = "${var.placement_tenancy}"
-  root_vol_del_on_term          = "${var.root_vol_del_on_term}"
-  root_vol_iops                 = "${var.root_vol_iops}"
-  root_vol_size                 = "${var.root_vol_size}"
-  root_vol_type                 = "${var.root_vol_type}"
-  security_groups               = ["${distinct(concat(list(module.consul.sg_id), compact(var.security_groups)))}"]
-  spot_price                    = "${var.spot_price}"
-  user_data                     = "${coalesce(var.user_data_override,data.template_file.user_data.rendered)}"
+  ami                           = coalesce(var.ami_override, data.aws_ami.ecs_ami.id)
+  associate_public_ip_address   = var.associate_public_ip_address
+  ebs_optimized                 = var.ebs_optimized
+  ebs_vol_del_on_term           = var.ebs_vol_del_on_term
+  ebs_vol_device_name           = var.ebs_vol_device_name
+  ebs_vol_encrypted             = var.ebs_vol_encrypted
+  ebs_vol_iops                  = var.ebs_vol_iops
+  ebs_vol_size                  = var.ebs_vol_size
+  ebs_vol_snapshot_id           = var.ebs_vol_snapshot_id
+  ebs_vol_type                  = var.ebs_vol_type
+  enable_monitoring             = var.enable_monitoring
+  instance_based_naming_enabled = var.instance_based_naming_enabled
+  instance_name_prefix          = var.instance_name_prefix
+  instance_profile              = aws_iam_instance_profile.agent_profile.id
+  instance_tags                 = var.instance_tags
+  instance_type                 = var.instance_type
+  key_name                      = var.key_name
+  placement_tenancy             = var.placement_tenancy
+  root_vol_del_on_term          = var.root_vol_del_on_term
+  root_vol_iops                 = var.root_vol_iops
+  root_vol_size                 = var.root_vol_size
+  root_vol_type                 = var.root_vol_type
+  security_groups               = distinct(concat([module.consul.sg_id], compact(var.security_groups)))
+  spot_price                    = var.spot_price
+  user_data = coalesce(
+    var.user_data_override,
+    data.template_file.user_data.rendered,
+  )
 
   # ASG parameters
-  default_cooldown          = "${var.default_cooldown}"
-  desired_capacity          = "${var.desired_capacity}"
-  enabled_metrics           = ["${var.enabled_metrics}"]
-  force_delete              = "${var.force_delete}"
-  hc_check_type             = "${var.hc_check_type}"
-  hc_grace_period           = "${var.hc_grace_period}"
-  max_size                  = "${var.max_size}"
-  min_size                  = "${var.min_size}"
-  placement_group           = "${var.placement_group}"
-  protect_from_scale_in     = "${var.protect_from_scale_in}"
-  suspended_processes       = ["${var.suspended_processes}"]
-  target_group_arns         = ["${var.target_group_arns}"]
-  termination_policies      = ["${var.termination_policies}"]
-  wait_for_capacity_timeout = "${var.wait_for_capacity_timeout}"
+  default_cooldown          = var.default_cooldown
+  desired_capacity          = var.desired_capacity
+  enabled_metrics           = var.enabled_metrics
+  force_delete              = var.force_delete
+  hc_check_type             = var.hc_check_type
+  hc_grace_period           = var.hc_grace_period
+  max_size                  = var.max_size
+  min_size                  = var.min_size
+  placement_group           = var.placement_group
+  protect_from_scale_in     = var.protect_from_scale_in
+  suspended_processes       = var.suspended_processes
+  target_group_arns         = var.target_group_arns
+  termination_policies      = var.termination_policies
+  wait_for_capacity_timeout = var.wait_for_capacity_timeout
 }
 
 ## Updates security groups
@@ -103,7 +102,7 @@ resource "aws_security_group_rule" "agent_egress" {
   cidr_blocks       = ["0.0.0.0/0"]
   from_port         = 0
   protocol          = -1
-  security_group_id = "${module.cluster.sg_id}"
+  security_group_id = module.cluster.sg_id
   to_port           = 0
   type              = "egress"
 }
@@ -118,31 +117,32 @@ module "consul" {
   source = "../consul"
 
   # Resource tags
-  stack_item_fullname = "${var.stack_item_fullname}"
+  stack_item_fullname = var.stack_item_fullname
   stack_item_label    = "${var.cluster_label}-${var.stack_item_label}"
 
   # ECS parameters
-  cluster_id    = "${aws_ecs_cluster.cluster.id}"
-  cluster_name  = "${aws_ecs_cluster.cluster.name}"
-  cluster_sg_id = "${module.cluster.sg_id}"
-  iam_path      = "${var.iam_path}"
-  vpc_id        = "${var.vpc_id}"
+  cluster_id    = aws_ecs_cluster.cluster.id
+  cluster_name  = aws_ecs_cluster.cluster.name
+  cluster_sg_id = module.cluster.sg_id
+  iam_path      = var.iam_path
+  vpc_id        = var.vpc_id
 
   # Service discovery parameters
   ## TODO: Enable for auto scaling
 
-  agent_config_override         = "${var.agent_config_override}"
-  agent_desired_count           = "${((length(var.desired_capacity) > 0 ? var.desired_capacity : var.min_size) - var.server_desired_count) >= 0 ? (var.min_size - var.server_desired_count) : "0"}"
-  agent_task_arn_override       = "${var.agent_task_arn_override}"
-  consul_dc                     = "${var.consul_dc}"
-  consul_docker_image           = "${var.consul_docker_image}"
-  registrator_config_override   = "${var.registrator_config_override}"
-  registrator_desired_count     = "${length(var.desired_capacity) > 0 ? var.desired_capacity : var.min_size}"
-  registrator_docker_image      = "${var.registrator_docker_image}"
-  registrator_task_arn_override = "${var.registrator_task_arn_override}"
-  server_config_override        = "${var.server_config_override}"
-  server_desired_count          = "${var.server_desired_count}"
-  server_task_arn_override      = "${var.server_task_arn_override}"
-  service_discovery_enabled     = "${(var.min_size - var.server_desired_count) < 0 ? "false" : var.service_discovery_enabled}"
-  service_registration_enabled  = "${var.service_registration_enabled}"
+  agent_config_override         = var.agent_config_override
+  agent_desired_count           = length(var.desired_capacity) > 0 ? var.desired_capacity : var.min_size - var.server_desired_count >= 0 ? var.min_size - var.server_desired_count : "0"
+  agent_task_arn_override       = var.agent_task_arn_override
+  consul_dc                     = var.consul_dc
+  consul_docker_image           = var.consul_docker_image
+  registrator_config_override   = var.registrator_config_override
+  registrator_desired_count     = length(var.desired_capacity) > 0 ? var.desired_capacity : var.min_size
+  registrator_docker_image      = var.registrator_docker_image
+  registrator_task_arn_override = var.registrator_task_arn_override
+  server_config_override        = var.server_config_override
+  server_desired_count          = var.server_desired_count
+  server_task_arn_override      = var.server_task_arn_override
+  service_discovery_enabled     = var.min_size - var.server_desired_count < 0 ? "false" : var.service_discovery_enabled
+  service_registration_enabled  = var.service_registration_enabled
 }
+
diff --git a/cluster/outputs.tf b/cluster/outputs.tf
index 1b549c4..a03855a 100644
--- a/cluster/outputs.tf
+++ b/cluster/outputs.tf
@@ -1,25 +1,26 @@
 # Outputs
 
 output "agent_role_id" {
-  value = "${aws_iam_role.agent_role.id}"
+  value = aws_iam_role.agent_role.id
 }
 
 output "cluster_id" {
-  value = "${aws_ecs_cluster.cluster.id}"
+  value = aws_ecs_cluster.cluster.id
 }
 
 output "cluster_name" {
-  value = "${aws_ecs_cluster.cluster.name}"
+  value = aws_ecs_cluster.cluster.name
 }
 
 output "consul_sg_id" {
-  value = "${module.consul.sg_id}"
+  value = module.consul.sg_id
 }
 
 output "consul_target_group_arn" {
-  value = "${module.consul.target_group_arn}"
+  value = module.consul.target_group_arn
 }
 
 output "sg_id" {
-  value = "${module.cluster.sg_id}"
+  value = module.cluster.sg_id
 }
+
diff --git a/cluster/variables.tf b/cluster/variables.tf
index 94bda61..12c4b9f 100644
--- a/cluster/variables.tf
+++ b/cluster/variables.tf
@@ -2,28 +2,28 @@
 
 ## Resource tags
 variable "cluster_label" {
-  type        = "string"
+  type        = string
   description = "Short form identifier for this cluster."
 }
 
 variable "stack_item_fullname" {
-  type        = "string"
+  type        = string
   description = "Long form descriptive name for this stack item. This value is used to create the 'application' resource tag for resources created by this stack item."
 }
 
 variable "stack_item_label" {
-  type        = "string"
+  type        = string
   description = "Short form identifier for this stack. This value is used to create the 'Name' resource tag for resources created by this stack item, and also serves as a unique key for re-use."
 }
 
 ## VPC parameters
 variable "subnets" {
-  type        = "list"
+  type        = list(string)
   description = "A list of subnet IDs to launch resources in."
 }
 
 variable "vpc_id" {
-  type        = "string"
+  type        = string
   description = "ID of the target VPC."
 }
 
@@ -31,37 +31,37 @@ variable "vpc_id" {
 
 ### LC parameters
 variable "ami_override" {
-  type        = "string"
+  type        = string
   description = "Custom Amazon Machine Image (AMI) to associate with the launch configuration."
   default     = ""
 }
 
 variable "associate_public_ip_address" {
-  type        = "string"
+  type        = string
   description = "Flag for associating public IP addresses with instances managed by the auto scaling group."
   default     = ""
 }
 
 variable "ebs_optimized" {
-  type        = "string"
+  type        = string
   description = "Flag to enable EBS optimization."
   default     = "false"
 }
 
 variable "ebs_vol_del_on_term" {
-  type        = "string"
+  type        = string
   description = "Whether the volume should be destroyed on instance termination."
   default     = "true"
 }
 
 variable "ebs_vol_device_name" {
-  type        = "string"
+  type        = string
   description = "The name of the device to mount."
   default     = ""
 }
 
 variable "ebs_vol_encrypted" {
-  type        = "string"
+  type        = string
   description = "Whether the volume should be encrypted or not. Do not use this option if you are using 'ebs_vol_snapshot_id' as the encrypted flag will be determined by the snapshot."
   default     = ""
 }
@@ -71,55 +71,55 @@ http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/EBSVolumeTypes.html
 For the best per-I/O latency experience, we recommend that you provision an IOPS-to-GiB ratio greater than 2:1. For example, a 2,000 IOPS volume should be smaller than 1,000 GiB.
 */
 variable "ebs_vol_iops" {
-  type        = "string"
+  type        = string
   description = "The amount of provisioned IOPS. Only utilized with 'ebs_vol_type' of 'io1'."
   default     = "2000"
 }
 
 variable "ebs_vol_size" {
-  type        = "string"
+  type        = string
   description = "The size of the volume in gigabytes."
   default     = ""
 }
 
 variable "ebs_vol_snapshot_id" {
-  type        = "string"
+  type        = string
   description = "The Snapshot ID to mount."
   default     = ""
 }
 
 variable "ebs_vol_type" {
-  type        = "string"
+  type        = string
   description = "The type of volume. Valid values are 'standard', 'gp2' and 'io1'."
   default     = "gp2"
 }
 
 variable "enable_monitoring" {
-  type        = "string"
+  type        = string
   description = "Flag to enable detailed monitoring."
   default     = ""
 }
 
 variable "iam_path" {
-  type        = "string"
+  type        = string
   description = "The path to the IAM resource."
   default     = "/"
 }
 
 variable "instance_based_naming_enabled" {
-  type        = "string"
+  type        = string
   description = "Flag to enable instance-id based name tagging. Requires the AWS CLI to be installed on the instance. Currently only supports Linux based systems."
   default     = ""
 }
 
 variable "instance_name_prefix" {
-  type        = "string"
+  type        = string
   description = "String to prepend instance-id based name tags with."
   default     = ""
 }
 
 variable "instance_tags" {
-  type        = "map"
+  type        = map(string)
   description = "Map of tags to add to instances. Requires the AWS CLI to be installed on the instance. Currently only supports Linux based systems."
 
   default = {
@@ -128,36 +128,36 @@ variable "instance_tags" {
 }
 
 variable "instance_type" {
-  type        = "string"
+  type        = string
   description = "The EC2 instance type to associate with the launch configuration."
 }
 
 variable "key_name" {
-  type        = "string"
+  type        = string
   description = "The SSH key pair to associate with the launch configuration."
   default     = ""
 }
 
 variable "logs_bucket_enabled" {
-  type        = "string"
+  type        = string
   description = "Flag for enabling access to the logs bucket from the instances."
   default     = "false"
 }
 
 variable "logs_bucket_name" {
-  type        = "string"
+  type        = string
   description = "Name of the S3 bucket for logging."
   default     = ""
 }
 
 variable "placement_tenancy" {
-  type        = "string"
+  type        = string
   description = "The tenancy of the instance. Valid values are 'default' or 'dedicated'."
   default     = "default"
 }
 
 variable "root_vol_del_on_term" {
-  type        = "string"
+  type        = string
   description = "Whether the volume should be destroyed on instance termination."
   default     = "true"
 }
@@ -167,193 +167,194 @@ http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/EBSVolumeTypes.html
 For the best per-I/O latency experience, we recommend that you provision an IOPS-to-GiB ratio greater than 2:1. For example, a 2,000 IOPS volume should be smaller than 1,000 GiB.
 */
 variable "root_vol_iops" {
-  type        = "string"
+  type        = string
   description = "The amount of provisioned IOPS. Only utilized with 'root_vol_type' of 'io1'"
   default     = "2000"
 }
 
 variable "root_vol_size" {
-  type        = "string"
+  type        = string
   description = "The size of the volume in gigabytes."
   default     = ""
 }
 
 variable "root_vol_type" {
-  type        = "string"
+  type        = string
   description = "The type of volume. Valid values are 'standard', 'gp2' and 'io1'."
   default     = "gp2"
 }
 
 variable "security_groups" {
-  type        = "list"
+  type        = list(string)
   description = "A list of security group IDs to associate with the instances."
   default     = []
 }
 
 variable "spot_price" {
-  type        = "string"
+  type        = string
   description = "The price to use for reserving spot instances."
   default     = ""
 }
 
 variable "user_data_override" {
-  type        = "string"
+  type        = string
   description = "Custom instance initialization data to associate with the launch configuration."
   default     = ""
 }
 
 ### ASG parameters
 variable "default_cooldown" {
-  type        = "string"
+  type        = string
   description = "The amount of time, in seconds, after a scaling activity completes before another scaling activity can start."
   default     = ""
 }
 
 variable "desired_capacity" {
-  type        = "string"
+  type        = string
   description = "The number of Amazon EC2 instances that should be running in the group."
   default     = ""
 }
 
 variable "enabled_metrics" {
-  type        = "list"
+  type        = list(string)
   description = "A list of metrics to collect. The allowed values are 'GroupMinSize', 'GroupMaxSize', 'GroupDesiredCapacity', 'GroupInServiceInstances', 'GroupPendingInstances', 'GroupStandbyInstances', 'GroupTerminatingInstances', 'GroupTotalInstances'."
   default     = []
 }
 
 variable "force_delete" {
-  type        = "string"
+  type        = string
   description = "Flag to allow deletion of the auto scaling group without waiting for all instances in the pool to terminate."
   default     = "false"
 }
 
 variable "hc_check_type" {
-  type        = "string"
+  type        = string
   description = "Type of health check performed by the auto scaling group. Valid values are 'ELB' or 'EC2'."
   default     = ""
 }
 
 variable "hc_grace_period" {
-  type        = "string"
+  type        = string
   description = "Time allowed after an instance comes into service before checking health."
   default     = ""
 }
 
 variable "max_size" {
-  type        = "string"
+  type        = string
   description = "The maximum number of instances allowed by the auto scaling group."
 }
 
 variable "min_size" {
-  type        = "string"
+  type        = string
   description = "The minimum number of instance to be maintained by the auto scaling group."
 }
 
 variable "placement_group" {
-  type        = "string"
+  type        = string
   description = "The name of the placement group into which you'll launch your instances, if any."
   default     = ""
 }
 
 variable "protect_from_scale_in" {
-  type        = "string"
+  type        = string
   description = "Allows setting instance protection. The autoscaling group will not select instances with this setting for terminination during scale in events."
   default     = ""
 }
 
 variable "suspended_processes" {
-  type        = "list"
+  type        = list(string)
   description = "A list of processes to suspend for the AutoScaling Group. The allowed values are 'Launch', 'Terminate', 'HealthCheck', 'ReplaceUnhealthy', 'AZRebalance', 'AlarmNotification', 'ScheduledActions', 'AddToLoadBalancer'. Note that if you suspend either the 'Launch' or 'Terminate' process types, it can prevent your autoscaling group from functioning properly."
   default     = []
 }
 
 variable "target_group_arns" {
-  type        = "list"
+  type        = list(string)
   description = "A list of 'aws_alb_target_group' ARNs, for use with Application Load Balancing"
   default     = []
 }
 
 variable "termination_policies" {
-  type        = "list"
+  type        = list(string)
   description = "A list of policies to decide how the instances in the auto scale group should be terminated. The allowed values are 'OldestInstance', 'NewestInstance', 'OldestLaunchConfiguration', 'ClosestToNextInstanceHour', 'Default'."
   default     = []
 }
 
 variable "wait_for_capacity_timeout" {
-  type        = "string"
+  type        = string
   description = "A maximum duration that Terraform should wait for ASG managed instances to become healthy before timing out."
   default     = ""
 }
 
 ## Service discovery parameters
 variable "agent_config_override" {
-  type        = "string"
+  type        = string
   description = "Consul agent ECS task configuration JSON."
   default     = ""
 }
 
 variable "agent_task_arn_override" {
-  type        = "string"
+  type        = string
   description = "Consul agent ECS task ARN."
   default     = ""
 }
 
 variable "consul_dc" {
-  type        = "string"
+  type        = string
   description = "Consul datacenter of the specified cluster."
   default     = "dc1"
 }
 
 variable "consul_docker_image" {
-  type        = "string"
+  type        = string
   description = "Consul Docker image and tag"
   default     = "consul:latest"
 }
 
 variable "registrator_config_override" {
-  type        = "string"
+  type        = string
   description = "Registrator ECS task configuration JSON."
   default     = ""
 }
 
 variable "registrator_docker_image" {
-  type        = "string"
+  type        = string
   description = "Registrator Docker image and tag"
   default     = "gliderlabs/registrator:v7"
 }
 
 variable "registrator_task_arn_override" {
-  type        = "string"
+  type        = string
   description = "Registrator ECS task ARN."
   default     = ""
 }
 
 variable "server_config_override" {
-  type        = "string"
+  type        = string
   description = "Consul server ECS task configuration JSON."
   default     = ""
 }
 
 variable "server_task_arn_override" {
-  type        = "string"
+  type        = string
   description = "Consul server ECS task ARN."
   default     = ""
 }
 
 variable "server_desired_count" {
-  type        = "string"
+  type        = string
   description = "The number of Consul server containers to run."
   default     = "3"
 }
 
 variable "service_discovery_enabled" {
-  type        = "string"
+  type        = string
   description = "Flag for the deployment of Consul service discovery and configuration."
   default     = "false"
 }
 
 variable "service_registration_enabled" {
-  type        = "string"
+  type        = string
   description = "Flag for the deployment of Registrator service registration."
   default     = "false"
 }
+
diff --git a/cluster/versions.tf b/cluster/versions.tf
new file mode 100644
index 0000000..ac97c6a
--- /dev/null
+++ b/cluster/versions.tf
@@ -0,0 +1,4 @@
+
+terraform {
+  required_version = ">= 0.12"
+}
diff --git a/consul/iam.tf b/consul/iam.tf
index cd3d467..cb7f7f7 100644
--- a/consul/iam.tf
+++ b/consul/iam.tf
@@ -2,7 +2,7 @@
 
 ## Creates IAM role for Consul ECS services
 data "aws_iam_policy_document" "consul_policy" {
-  count = "${local.service_discovery_check}"
+  count = local.service_discovery_check
 
   statement {
     actions = ["sts:AssumeRole"]
@@ -16,15 +16,15 @@ data "aws_iam_policy_document" "consul_policy" {
 }
 
 resource "aws_iam_role" "consul_role" {
-  count = "${local.service_discovery_check}"
+  count = local.service_discovery_check
 
-  assume_role_policy = "${data.aws_iam_policy_document.consul_policy.json}"
+  assume_role_policy = data.aws_iam_policy_document.consul_policy[0].json
   name               = "consul-${var.stack_item_label}-${data.aws_region.current.name}"
-  path               = "${var.iam_path}"
+  path               = var.iam_path
 }
 
 data "aws_iam_policy_document" "consul_ec2_policy" {
-  count = "${local.service_discovery_check}"
+  count = local.service_discovery_check
 
   statement {
     actions = [
@@ -37,16 +37,16 @@ data "aws_iam_policy_document" "consul_ec2_policy" {
 }
 
 resource "aws_iam_role_policy" "consul_ec2_policy" {
-  count = "${local.service_discovery_check}"
+  count = local.service_discovery_check
 
   name   = "ec2"
-  policy = "${data.aws_iam_policy_document.consul_ec2_policy.json}"
-  role   = "${aws_iam_role.consul_role.id}"
+  policy = data.aws_iam_policy_document.consul_ec2_policy[0].json
+  role   = aws_iam_role.consul_role[0].id
 }
 
 ## Creates IAM role for the ECS service
 data "aws_iam_policy_document" "ecs_policy" {
-  count = "${local.service_discovery_check * local.consul_server_check}"
+  count = local.service_discovery_check * local.consul_server_check
 
   statement {
     actions = ["sts:AssumeRole"]
@@ -60,11 +60,11 @@ data "aws_iam_policy_document" "ecs_policy" {
 }
 
 resource "aws_iam_role" "ecs_role" {
-  count = "${local.service_discovery_check * local.consul_server_check}"
+  count = local.service_discovery_check * local.consul_server_check
 
-  assume_role_policy = "${data.aws_iam_policy_document.ecs_policy.json}"
+  assume_role_policy = data.aws_iam_policy_document.ecs_policy[0].json
   name               = "ecs-consul-${var.stack_item_label}-${data.aws_region.current.name}"
-  path               = "${var.iam_path}"
+  path               = var.iam_path
 }
 
 data "aws_iam_policy_document" "lb_policy" {
@@ -85,11 +85,11 @@ data "aws_iam_policy_document" "lb_policy" {
 }
 
 resource "aws_iam_role_policy" "lb_policy" {
-  count = "${local.service_discovery_check * local.consul_server_check}"
+  count = local.service_discovery_check * local.consul_server_check
 
   name   = "lb"
-  policy = "${data.aws_iam_policy_document.lb_policy.json}"
-  role   = "${aws_iam_role.ecs_role.id}"
+  policy = data.aws_iam_policy_document.lb_policy.json
+  role   = aws_iam_role.ecs_role[0].id
 }
 
 data "aws_iam_policy_document" "ecs_ec2_policy" {
@@ -105,9 +105,10 @@ data "aws_iam_policy_document" "ecs_ec2_policy" {
 }
 
 resource "aws_iam_role_policy" "ecs_ec2_policy" {
-  count = "${local.service_discovery_check * local.consul_server_check}"
+  count = local.service_discovery_check * local.consul_server_check
 
   name   = "ec2"
-  policy = "${data.aws_iam_policy_document.ecs_ec2_policy.json}"
-  role   = "${aws_iam_role.ecs_role.id}"
+  policy = data.aws_iam_policy_document.ecs_ec2_policy.json
+  role   = aws_iam_role.ecs_role[0].id
 }
+
diff --git a/consul/main.tf b/consul/main.tf
index 3fc8716..a6497f1 100644
--- a/consul/main.tf
+++ b/consul/main.tf
@@ -1,30 +1,26 @@
 # Consul service discovery & configuration
 
-## Set Terraform version constraint
-terraform {
-  required_version = "> 0.11.0"
+data "aws_region" "current" {
 }
 
-data "aws_region" "current" {}
-
 locals {
-  service_discovery_check = "${var.service_discovery_enabled == "true" ? 1 : 0}"
-  consul_server_check     = "${var.server_desired_count > 0 ? 1 : 0}"
-  consul_agent_check      = "${var.agent_desired_count > 0 ? 1 : 0}"
-  registrator_check       = "${var.service_registration_enabled == "true" ? 1 : 0}"
+  service_discovery_check = var.service_discovery_enabled == "true" ? 1 : 0
+  consul_server_check     = var.server_desired_count > 0 ? 1 : 0
+  consul_agent_check      = var.agent_desired_count > 0 ? 1 : 0
+  registrator_check       = var.service_registration_enabled == "true" ? 1 : 0
 }
 
 ## Creates Consul communication security group
 
 resource "aws_security_group" "consul_sg" {
-  count = "${local.service_discovery_check * local.consul_server_check}"
+  count = local.service_discovery_check * local.consul_server_check
 
   description = "${var.stack_item_fullname} Consul security group"
   name_prefix = "consul-${var.stack_item_label}-"
-  vpc_id      = "${var.vpc_id}"
+  vpc_id      = var.vpc_id
 
-  tags {
-    application = "${var.stack_item_fullname}"
+  tags = {
+    application = var.stack_item_fullname
     managed_by  = "terraform"
     Name        = "consul-${var.stack_item_label}"
   }
@@ -36,66 +32,66 @@ resource "aws_security_group" "consul_sg" {
 
 ### Traffic within the environment
 resource "aws_security_group_rule" "agent_consul_rpc" {
-  count = "${local.service_discovery_check * local.consul_server_check}"
+  count = local.service_discovery_check * local.consul_server_check
 
   from_port         = 8300
   protocol          = "tcp"
-  security_group_id = "${aws_security_group.consul_sg.id}"
+  security_group_id = aws_security_group.consul_sg[0].id
   self              = true
   to_port           = 8300
   type              = "ingress"
 }
 
 resource "aws_security_group_rule" "agent_serf_lan_tcp" {
-  count = "${local.service_discovery_check * local.consul_server_check}"
+  count = local.service_discovery_check * local.consul_server_check
 
   from_port         = 8301
   protocol          = "tcp"
-  security_group_id = "${aws_security_group.consul_sg.id}"
+  security_group_id = aws_security_group.consul_sg[0].id
   self              = true
   to_port           = 8301
   type              = "ingress"
 }
 
 resource "aws_security_group_rule" "agent_serf_lan_udp" {
-  count = "${local.service_discovery_check * local.consul_server_check}"
+  count = local.service_discovery_check * local.consul_server_check
 
   from_port         = 8301
   protocol          = "udp"
-  security_group_id = "${aws_security_group.consul_sg.id}"
+  security_group_id = aws_security_group.consul_sg[0].id
   self              = true
   to_port           = 8301
   type              = "ingress"
 }
 
 resource "aws_security_group_rule" "agent_serf_wan_tcp" {
-  count = "${local.service_discovery_check * local.consul_server_check}"
+  count = local.service_discovery_check * local.consul_server_check
 
   from_port         = 8302
   protocol          = "tcp"
-  security_group_id = "${aws_security_group.consul_sg.id}"
+  security_group_id = aws_security_group.consul_sg[0].id
   self              = true
   to_port           = 8302
   type              = "ingress"
 }
 
 resource "aws_security_group_rule" "agent_serf_wan_udp" {
-  count = "${local.service_discovery_check * local.consul_server_check}"
+  count = local.service_discovery_check * local.consul_server_check
 
   from_port         = 8302
   protocol          = "udp"
-  security_group_id = "${aws_security_group.consul_sg.id}"
+  security_group_id = aws_security_group.consul_sg[0].id
   self              = true
   to_port           = 8302
   type              = "ingress"
 }
 
 resource "aws_security_group_rule" "agent_http" {
-  count = "${local.service_discovery_check * local.consul_server_check}"
+  count = local.service_discovery_check * local.consul_server_check
 
   from_port         = 8500
   protocol          = "tcp"
-  security_group_id = "${aws_security_group.consul_sg.id}"
+  security_group_id = aws_security_group.consul_sg[0].id
   self              = true
   to_port           = 8500
   type              = "ingress"
@@ -103,12 +99,12 @@ resource "aws_security_group_rule" "agent_http" {
 
 ## Creates ALB target group
 resource "aws_alb_target_group" "consul_group" {
-  count = "${local.service_discovery_check * local.consul_server_check}"
+  count = local.service_discovery_check * local.consul_server_check
 
   name     = "consul-${var.stack_item_label}"
   port     = 8500
   protocol = "HTTP"
-  vpc_id   = "${var.vpc_id}"
+  vpc_id   = var.vpc_id
 
   health_check {
     path     = "/v1/agent/self"
@@ -116,8 +112,8 @@ resource "aws_alb_target_group" "consul_group" {
     protocol = "HTTP"
   }
 
-  tags {
-    application = "${var.stack_item_fullname}"
+  tags = {
+    application = var.stack_item_fullname
     Name        = "consul-${var.stack_item_label}"
     managed_by  = "terraform"
   }
@@ -127,25 +123,28 @@ resource "aws_alb_target_group" "consul_group" {
 
 ### Consul server
 data "template_file" "server_config" {
-  count = "${local.service_discovery_check * local.consul_server_check}"
+  count = local.service_discovery_check * local.consul_server_check
 
-  template = "${file("${path.module}/templates/server.hcl")}"
+  template = file("${path.module}/templates/server.hcl")
 
-  vars {
-    bootstrap_expect = "${var.server_desired_count}"
-    consul_dc        = "${var.consul_dc}"
-    docker_image     = "${var.consul_docker_image}"
-    join             = "${var.cluster_name}"
+  vars = {
+    bootstrap_expect = var.server_desired_count
+    consul_dc        = var.consul_dc
+    docker_image     = var.consul_docker_image
+    join             = var.cluster_name
   }
 }
 
 resource "aws_ecs_task_definition" "server_task" {
-  count = "${local.service_discovery_check * local.consul_server_check}"
+  count = local.service_discovery_check * local.consul_server_check
 
-  container_definitions = "${coalesce(var.server_config_override,data.template_file.server_config.rendered)}"
-  family                = "consul-server-${var.stack_item_label}"
-  network_mode          = "host"
-  task_role_arn         = "${aws_iam_role.consul_role.arn}"
+  container_definitions = coalesce(
+    var.server_config_override,
+    data.template_file.server_config[0].rendered,
+  )
+  family        = "consul-server-${var.stack_item_label}"
+  network_mode  = "host"
+  task_role_arn = aws_iam_role.consul_role[0].arn
 
   volume {
     host_path = "/etc/consul.d"
@@ -160,24 +159,27 @@ resource "aws_ecs_task_definition" "server_task" {
 
 ### Consul agent
 data "template_file" "agent_config" {
-  count = "${local.service_discovery_check * local.consul_agent_check}"
+  count = local.service_discovery_check * local.consul_agent_check
 
-  template = "${file("${path.module}/templates/agent.hcl")}"
+  template = file("${path.module}/templates/agent.hcl")
 
-  vars {
-    consul_dc    = "${var.consul_dc}"
-    docker_image = "${var.consul_docker_image}"
-    join         = "${var.cluster_name}"
+  vars = {
+    consul_dc    = var.consul_dc
+    docker_image = var.consul_docker_image
+    join         = var.cluster_name
   }
 }
 
 resource "aws_ecs_task_definition" "agent_task" {
-  count = "${local.service_discovery_check * local.consul_agent_check}"
+  count = local.service_discovery_check * local.consul_agent_check
 
-  container_definitions = "${coalesce(var.agent_config_override,data.template_file.agent_config.rendered)}"
-  family                = "consul-agent-${var.stack_item_label}"
-  network_mode          = "host"
-  task_role_arn         = "${aws_iam_role.consul_role.arn}"
+  container_definitions = coalesce(
+    var.agent_config_override,
+    data.template_file.agent_config[0].rendered,
+  )
+  family        = "consul-agent-${var.stack_item_label}"
+  network_mode  = "host"
+  task_role_arn = aws_iam_role.consul_role[0].arn
 
   volume {
     host_path = "/etc/consul.d"
@@ -192,21 +194,24 @@ resource "aws_ecs_task_definition" "agent_task" {
 
 ### Registrator
 data "template_file" "registrator_config" {
-  count = "${local.service_discovery_check * local.registrator_check}"
+  count = local.service_discovery_check * local.registrator_check
 
-  template = "${file("${path.module}/templates/registrator.hcl")}"
+  template = file("${path.module}/templates/registrator.hcl")
 
-  vars {
-    docker_image = "${var.registrator_docker_image}"
+  vars = {
+    docker_image = var.registrator_docker_image
   }
 }
 
 resource "aws_ecs_task_definition" "registrator_task" {
-  count = "${local.service_discovery_check * local.registrator_check}"
+  count = local.service_discovery_check * local.registrator_check
 
-  container_definitions = "${coalesce(var.registrator_config_override,data.template_file.registrator_config.rendered)}"
-  family                = "registrator-${var.stack_item_label}"
-  network_mode          = "host"
+  container_definitions = coalesce(
+    var.registrator_config_override,
+    data.template_file.registrator_config[0].rendered,
+  )
+  family       = "registrator-${var.stack_item_label}"
+  network_mode = "host"
 
   volume {
     host_path = "/var/run/docker.sock"
@@ -218,21 +223,24 @@ resource "aws_ecs_task_definition" "registrator_task" {
 
 ### Consul server
 resource "aws_ecs_service" "consul_server" {
-  count      = "${local.service_discovery_check * local.consul_server_check}"
-  depends_on = ["aws_iam_role.ecs_role"]
+  count      = local.service_discovery_check * local.consul_server_check
+  depends_on = [aws_iam_role.ecs_role]
 
-  cluster                            = "${var.cluster_id}"
+  cluster                            = var.cluster_id
   deployment_maximum_percent         = "100"
   deployment_minimum_healthy_percent = "50"
-  desired_count                      = "${var.server_desired_count}"
-  iam_role                           = "${aws_iam_role.ecs_role.arn}"
+  desired_count                      = var.server_desired_count
+  iam_role                           = aws_iam_role.ecs_role[0].arn
   name                               = "consul-server"
-  task_definition                    = "${coalesce(var.server_task_arn_override,aws_ecs_task_definition.server_task.arn)}"
+  task_definition = coalesce(
+    var.server_task_arn_override,
+    aws_ecs_task_definition.server_task[0].arn,
+  )
 
   load_balancer {
     container_name   = "consul-server"
     container_port   = "8500"
-    target_group_arn = "${aws_alb_target_group.consul_group.arn}"
+    target_group_arn = aws_alb_target_group.consul_group[0].arn
   }
 
   placement_constraints {
@@ -242,14 +250,17 @@ resource "aws_ecs_service" "consul_server" {
 
 ### Consul agent
 resource "aws_ecs_service" "consul_agent" {
-  count = "${local.service_discovery_check * local.consul_agent_check}"
+  count = local.service_discovery_check * local.consul_agent_check
 
-  cluster                            = "${var.cluster_id}"
+  cluster                            = var.cluster_id
   deployment_maximum_percent         = "100"
   deployment_minimum_healthy_percent = "50"
-  desired_count                      = "${var.agent_desired_count}"
+  desired_count                      = var.agent_desired_count
   name                               = "consul-agent"
-  task_definition                    = "${coalesce(var.agent_task_arn_override,aws_ecs_task_definition.agent_task.arn)}"
+  task_definition = coalesce(
+    var.agent_task_arn_override,
+    aws_ecs_task_definition.agent_task[0].arn,
+  )
 
   placement_constraints {
     type = "distinctInstance"
@@ -258,16 +269,20 @@ resource "aws_ecs_service" "consul_agent" {
 
 ### Registrator
 resource "aws_ecs_service" "registrator" {
-  count = "${local.service_discovery_check * local.registrator_check}"
+  count = local.service_discovery_check * local.registrator_check
 
-  cluster                            = "${var.cluster_id}"
+  cluster                            = var.cluster_id
   deployment_maximum_percent         = "100"
   deployment_minimum_healthy_percent = "50"
-  desired_count                      = "${var.registrator_desired_count}"
+  desired_count                      = var.registrator_desired_count
   name                               = "registrator"
-  task_definition                    = "${coalesce(var.registrator_task_arn_override,aws_ecs_task_definition.registrator_task.arn)}"
+  task_definition = coalesce(
+    var.registrator_task_arn_override,
+    aws_ecs_task_definition.registrator_task[0].arn,
+  )
 
   placement_constraints {
     type = "distinctInstance"
   }
 }
+
diff --git a/consul/outputs.tf b/consul/outputs.tf
index 2303ea3..afa52ab 100644
--- a/consul/outputs.tf
+++ b/consul/outputs.tf
@@ -1,9 +1,10 @@
 # Outputs
 
 output "sg_id" {
-  value = "${join(",", compact(aws_security_group.consul_sg.*.id))}"
+  value = join(",", compact(aws_security_group.consul_sg.*.id))
 }
 
 output "target_group_arn" {
-  value = "${join(",", compact(aws_alb_target_group.consul_group.*.arn))}"
+  value = join(",", compact(aws_alb_target_group.consul_group.*.arn))
 }
+
diff --git a/consul/variables.tf b/consul/variables.tf
index 6526f31..82abaaf 100644
--- a/consul/variables.tf
+++ b/consul/variables.tf
@@ -2,91 +2,92 @@
 
 ## Resource tags
 variable "stack_item_fullname" {
-  type = "string"
+  type = string
 }
 
 variable "stack_item_label" {
-  type = "string"
+  type = string
 }
 
 ## ECS parameters
 variable "cluster_id" {
-  type        = "string"
+  type        = string
   description = "ECS cluster ID."
 }
 
 variable "cluster_name" {
-  type        = "string"
+  type        = string
   description = "ECS cluster name."
 }
 
 variable "cluster_sg_id" {
-  type        = "string"
+  type        = string
   description = "ECS cluster security group ID."
 }
 
 variable "iam_path" {
-  type = "string"
+  type = string
 }
 
 variable "vpc_id" {
-  type        = "string"
+  type        = string
   description = "ID of the target VPC."
 }
 
 ## Service discovery parameters
 variable "agent_config_override" {
-  type = "string"
+  type = string
 }
 
 variable "agent_desired_count" {
-  type = "string"
+  type = string
 }
 
 variable "agent_task_arn_override" {
-  type = "string"
+  type = string
 }
 
 variable "consul_dc" {
-  type = "string"
+  type = string
 }
 
 variable "consul_docker_image" {
-  type = "string"
+  type = string
 }
 
 variable "registrator_config_override" {
-  type = "string"
+  type = string
 }
 
 variable "registrator_desired_count" {
-  type = "string"
+  type = string
 }
 
 variable "registrator_docker_image" {
-  type = "string"
+  type = string
 }
 
 variable "registrator_task_arn_override" {
-  type = "string"
+  type = string
 }
 
 variable "server_config_override" {
-  type = "string"
+  type = string
 }
 
 variable "server_desired_count" {
-  type = "string"
+  type = string
 }
 
 variable "server_task_arn_override" {
-  type = "string"
+  type = string
 }
 
 variable "service_discovery_enabled" {
-  type = "string"
+  type = string
 }
 
 variable "service_registration_enabled" {
-  type = "string"
+  type = string
 }
+
diff --git a/consul/versions.tf b/consul/versions.tf
new file mode 100644
index 0000000..ac97c6a
--- /dev/null
+++ b/consul/versions.tf
@@ -0,0 +1,4 @@
+
+terraform {
+  required_version = ">= 0.12"
+}
diff --git a/data/globals.yaml b/data/globals.yaml
index 76d561f..cda690d 100644
--- a/data/globals.yaml
+++ b/data/globals.yaml
@@ -2,5 +2,5 @@
 # Global variables
 
 ## Terraform
-tf_state_bucket: 'unifio-terraform-state'
-tf_state_region: 'us-east-2'
+tf_state_bucket: 'unifio-terrraform-state-us-east-1'
+tf_state_region: 'us-east-1'
diff --git a/data/stacks/common.yaml b/data/stacks/common.yaml
index 3bcd315..02600ce 100644
--- a/data/stacks/common.yaml
+++ b/data/stacks/common.yaml
@@ -3,13 +3,14 @@
 
 ## Complete examples
 examples::complete::vars:
-  ami_override: 'ami-abf2a9ce' # amzn-ami-2016.03.j-amazon-ecs-optimized
+  # https://us-east-1.console.aws.amazon.com/systems-manager/parameters/aws/service/ecs/optimized-ami/amazon-linux/recommended/image_id/description?region=us-east-1
+  ami_override: 'ami-040d7258a1baecb27'
   cluster_label: 'exmpl'
   enable_monitoring: 'true'
   iam_path: '/terraform/'
   instance_based_naming_enabled: 'true'
   instance_type: 't2.nano'
-  region: 'us-east-2'
+  region: 'us-east-1'
   stack_item_label: 'cmpl'
   stack_item_fullname: 'Complete Examples'
   subnets:
diff --git a/data/stacks/defaults.yaml b/data/stacks/defaults.yaml
index 2ae8776..3d4f2aa 100644
--- a/data/stacks/defaults.yaml
+++ b/data/stacks/defaults.yaml
@@ -17,7 +17,7 @@ examples::basic::vars:
   instance_type: 't2.nano'
   max_size: '3'
   min_size: '2'
-  region: 'us-east-2'
+  region: 'us-east-1'
   stack_item_fullname: 'Basic Examples'
   stack_item_label: 'bsc'
   subnets:
diff --git a/data/stacks/networking.yaml b/data/stacks/networking.yaml
index 4202f6e..0c2e833 100644
--- a/data/stacks/networking.yaml
+++ b/data/stacks/networking.yaml
@@ -13,6 +13,6 @@ networking::state:
 
 ## Input variables
 examples::prereqs::vars:
-  region: 'us-east-2'
+  region: 'us-east-1'
   stack_item_fullname: 'ECS Examples'
   stack_item_label: 'ecs-exmpl'
diff --git a/data/stacks/overrides.yaml b/data/stacks/overrides.yaml
index ed5f1a9..b301d0d 100644
--- a/data/stacks/overrides.yaml
+++ b/data/stacks/overrides.yaml
@@ -13,7 +13,8 @@ overrides::state:
 
 ## Input variables
 examples::complete::vars:
-  ami_override: 'ami-abf2a9ce' # amzn-ami-2016.03.j-amazon-ecs-optimized
+  # https://us-east-1.console.aws.amazon.com/systems-manager/parameters/aws/service/ecs/optimized-ami/amazon-linux/recommended/image_id/description?region=us-east-1
+  ami_override: 'ami-040d7258a1baecb27'
   cluster_label: 'exmpl'
   enable_monitoring: 'true'
   iam_path: '/terraform/'
@@ -21,7 +22,7 @@ examples::complete::vars:
   instance_type: 't2.small'
   max_size: '3'
   min_size: '2'
-  region: 'us-east-2'
+  region: 'us-east-1'
   stack_item_fullname: 'Complete Examples'
   stack_item_label: 'cmpl'
   subnets:
diff --git a/examples/basic/main.tf b/examples/basic/main.tf
index 198bf88..9b8ab1d 100644
--- a/examples/basic/main.tf
+++ b/examples/basic/main.tf
@@ -2,7 +2,7 @@
 
 ## Configures AWS provider
 provider "aws" {
-  region = "${var.region}"
+  region = var.region
 }
 
 ## Configures ECS cluster
@@ -12,15 +12,15 @@ module "cluster" {
   source = "../../cluster"
 
   # Resource tags
-  cluster_label       = "${var.cluster_label}"
-  stack_item_fullname = "${var.stack_item_fullname}"
-  stack_item_label    = "${var.stack_item_label}"
+  cluster_label       = var.cluster_label
+  stack_item_fullname = var.stack_item_fullname
+  stack_item_label    = var.stack_item_label
 
   # Cluster parameters
   associate_public_ip_address = "true"
-  instance_type               = "${var.instance_type}"
-  max_size                    = "${var.max_size}"
-  min_size                    = "${var.min_size}"
-  subnets                     = ["${var.subnets}"]
-  vpc_id                      = "${var.vpc_id}"
+  instance_type               = var.instance_type
+  max_size                    = var.max_size
+  min_size                    = var.min_size
+  subnets                     = var.subnets
+  vpc_id                      = var.vpc_id
 }
diff --git a/examples/basic/variables.tf b/examples/basic/variables.tf
index 36fbbe9..f8035f1 100644
--- a/examples/basic/variables.tf
+++ b/examples/basic/variables.tf
@@ -2,38 +2,38 @@
 
 ## Resource tags
 variable "cluster_label" {
-  type = "string"
+  type = string
 }
 
 variable "stack_item_fullname" {
-  type = "string"
+  type = string
 }
 
 variable "stack_item_label" {
-  type = "string"
+  type = string
 }
 
 ## Cluster parameters
 variable "instance_type" {
-  type = "string"
+  type = string
 }
 
 variable "max_size" {
-  type = "string"
+  type = string
 }
 
 variable "min_size" {
-  type = "string"
+  type = string
 }
 
 variable "region" {
-  type = "string"
+  type = string
 }
 
 variable "subnets" {
-  type = "list"
+  type = list(string)
 }
 
 variable "vpc_id" {
-  type = "string"
+  type = string
 }
diff --git a/examples/complete/main.tf b/examples/complete/main.tf
index 5f7599b..803fbf2 100644
--- a/examples/complete/main.tf
+++ b/examples/complete/main.tf
@@ -2,7 +2,7 @@
 
 ## Configures AWS provider
 provider "aws" {
-  region = "${var.region}"
+  region = var.region
 }
 
 ## Creates logs bucket
@@ -17,11 +17,11 @@ resource "aws_s3_bucket" "logs" {
 
 ## Creates cloud-config
 data "template_file" "init" {
-  template = "${file("${path.module}/user_data.hcl")}"
+  template = file("${path.module}/user_data.hcl")
 
-  vars {
-    cluster_label    = "${var.cluster_label}"
-    stack_item_label = "${var.stack_item_label}"
+  vars = {
+    cluster_label    = var.cluster_label
+    stack_item_label = var.stack_item_label
   }
 }
 
@@ -32,33 +32,33 @@ module "cluster" {
   source = "../../cluster"
 
   # Resource tags
-  cluster_label       = "${var.cluster_label}"
-  stack_item_fullname = "${var.stack_item_fullname}"
-  stack_item_label    = "${var.stack_item_label}"
+  cluster_label       = var.cluster_label
+  stack_item_fullname = var.stack_item_fullname
+  stack_item_label    = var.stack_item_label
 
   # Cluster parameters
   associate_public_ip_address   = "true"
-  ami_override                  = "${var.ami_override}"
-  enable_monitoring             = "${var.enable_monitoring}"
-  iam_path                      = "${var.iam_path}"
-  instance_based_naming_enabled = "${var.instance_based_naming_enabled}"
+  ami_override                  = var.ami_override
+  enable_monitoring             = var.enable_monitoring
+  iam_path                      = var.iam_path
+  instance_based_naming_enabled = var.instance_based_naming_enabled
 
   instance_tags = {
     "env" = "example"
   }
 
-  instance_type       = "${var.instance_type}"
+  instance_type       = var.instance_type
   logs_bucket_enabled = "true"
-  logs_bucket_name    = "${aws_s3_bucket.logs.id}"
-  max_size            = "${var.max_size}"
-  min_size            = "${var.min_size}"
-  subnets             = ["${var.subnets}"]
-  user_data_override  = "${data.template_file.init.rendered}"
-  vpc_id              = "${var.vpc_id}"
+  logs_bucket_name    = aws_s3_bucket.logs.id
+  max_size            = var.max_size
+  min_size            = var.min_size
+  subnets             = var.subnets
+  user_data_override  = data.template_file.init.rendered
+  vpc_id              = var.vpc_id
 
   # Service discovery parameters
-  service_discovery_enabled    = "${var.service_discovery_enabled}"
-  service_registration_enabled = "${var.service_registration_enabled}"
+  service_discovery_enabled    = var.service_discovery_enabled
+  service_registration_enabled = var.service_registration_enabled
 }
 
 # Configures ALB for internal dashboards
@@ -67,10 +67,10 @@ module "cluster" {
 resource "aws_security_group" "lb" {
   name_prefix = "${var.stack_item_label}-lb-"
   description = "${var.stack_item_fullname} load balancer security group"
-  vpc_id      = "${var.vpc_id}"
+  vpc_id      = var.vpc_id
 
-  tags {
-    application = "${var.stack_item_fullname}"
+  tags = {
+    application = var.stack_item_fullname
     managed_by  = "terraform"
     Name        = "${var.stack_item_label}-lb"
   }
@@ -81,7 +81,7 @@ resource "aws_security_group_rule" "lb_egress" {
   cidr_blocks       = ["0.0.0.0/0"]
   from_port         = 0
   protocol          = -1
-  security_group_id = "${aws_security_group.lb.id}"
+  security_group_id = aws_security_group.lb.id
   to_port           = 0
   type              = "egress"
 }
@@ -90,20 +90,20 @@ resource "aws_security_group_rule" "lb_http" {
   cidr_blocks       = ["0.0.0.0/0"]
   from_port         = 80
   protocol          = "tcp"
-  security_group_id = "${aws_security_group.lb.id}"
+  security_group_id = aws_security_group.lb.id
   to_port           = 80
   type              = "ingress"
 }
 
 resource "aws_alb" "lb" {
   name            = "${var.cluster_label}-${var.stack_item_label}"
-  security_groups = ["${aws_security_group.lb.id}", "${module.cluster.consul_sg_id}"]
-  subnets         = ["${var.subnets}"]
+  security_groups = [aws_security_group.lb.id, module.cluster.consul_sg_id]
+  subnets         = var.subnets
 
-  tags {
-    application = "${var.stack_item_fullname}"
+  tags = {
+    application = var.stack_item_fullname
     managed_by  = "terraform"
-    Name        = "${var.stack_item_label}"
+    Name        = var.stack_item_label
   }
 }
 
@@ -111,44 +111,44 @@ resource "aws_alb_target_group" "default" {
   name     = "default-${var.stack_item_label}"
   port     = 80
   protocol = "HTTP"
-  vpc_id   = "${var.vpc_id}"
+  vpc_id   = var.vpc_id
 
   health_check {
     port     = 80
     protocol = "HTTP"
   }
 
-  tags {
-    application = "${var.stack_item_fullname}"
+  tags = {
+    application = var.stack_item_fullname
     Name        = "default-${var.stack_item_label}"
     managed_by  = "terraform"
   }
 }
 
 resource "aws_alb_listener" "admin" {
-  load_balancer_arn = "${aws_alb.lb.arn}"
+  load_balancer_arn = aws_alb.lb.arn
   port              = 80
   protocol          = "HTTP"
 
   default_action {
-    target_group_arn = "${aws_alb_target_group.default.arn}"
+    target_group_arn = aws_alb_target_group.default.arn
     type             = "forward"
   }
 }
 
 resource "aws_alb_listener_rule" "consul_rule" {
-  count = "${var.service_discovery_enabled == "true" ? 1 : 0}"
+  count = var.service_discovery_enabled == "true" ? 1 : 0
 
-  listener_arn = "${aws_alb_listener.admin.arn}"
+  listener_arn = aws_alb_listener.admin.arn
   priority     = 100
 
   action {
     type             = "forward"
-    target_group_arn = "${module.cluster.consul_target_group_arn}"
+    target_group_arn = module.cluster.consul_target_group_arn
   }
-
   condition {
-    field  = "path-pattern"
-    values = ["/*"]
+    path_pattern {
+      values = ["/*"]
+    }
   }
 }
diff --git a/examples/complete/variables.tf b/examples/complete/variables.tf
index 1814c4c..329260b 100644
--- a/examples/complete/variables.tf
+++ b/examples/complete/variables.tf
@@ -2,65 +2,65 @@
 
 ## Resource tags
 variable "cluster_label" {
-  type = "string"
+  type = string
 }
 
 variable "stack_item_fullname" {
-  type = "string"
+  type = string
 }
 
 variable "stack_item_label" {
-  type = "string"
+  type = string
 }
 
 ## Cluster parameters
 variable "ami_override" {
-  type = "string"
+  type = string
 }
 
 variable "enable_monitoring" {
-  type = "string"
+  type = string
 }
 
 variable "iam_path" {
-  type = "string"
+  type = string
 }
 
 variable "instance_based_naming_enabled" {
-  type = "string"
+  type = string
 }
 
 variable "instance_type" {
-  type = "string"
+  type = string
 }
 
 variable "max_size" {
-  type = "string"
+  type = string
 }
 
 variable "min_size" {
-  type = "string"
+  type = string
 }
 
 variable "region" {
-  type = "string"
+  type = string
 }
 
 variable "subnets" {
-  type = "list"
+  type = list(string)
 }
 
 variable "vpc_id" {
-  type = "string"
+  type = string
 }
 
 ## Service discovery parameters
 variable "service_discovery_enabled" {
-  type    = "string"
+  type    = string
   default = "false"
 }
 
 variable "service_registration_enabled" {
-  type    = "string"
+  type    = string
   default = "false"
 }
diff --git a/examples/prereqs/main.tf b/examples/prereqs/main.tf
index ad55d50..ef1168b 100644
--- a/examples/prereqs/main.tf
+++ b/examples/prereqs/main.tf
@@ -2,34 +2,34 @@
 
 ## Configures AWS provider
 provider "aws" {
-  region = "${var.region}"
+  region = var.region
 }
 
 ## Configures base VPC
 module "vpc_base" {
-  source = "github.com/unifio/terraform-aws-vpc?ref=v0.4.0//base"
+  source = "github.com/unifio/terraform-aws-vpc?ref=upgrade-0.12//base"
 
   enable_dns          = "true"
-  stack_item_fullname = "${var.stack_item_fullname}"
-  stack_item_label    = "${var.stack_item_label}"
+  stack_item_fullname = var.stack_item_fullname
+  stack_item_label    = var.stack_item_label
   vpc_cidr            = "172.16.0.0/24"
 }
 
 ## Configures VPC availabilty zones
 module "vpc_az" {
-  source = "github.com/unifio/terraform-aws-vpc?ref=v0.4.0//az"
+  source = "github.com/unifio/terraform-aws-vpc?ref=upgrade-0.12//az"
 
   azs_provisioned     = 2
   lans_per_az         = 0
-  rt_dmz_id           = "${module.vpc_base.rt_dmz_id}"
-  stack_item_fullname = "${var.stack_item_fullname}"
-  stack_item_label    = "${var.stack_item_label}"
-  vpc_id              = "${module.vpc_base.vpc_id}"
+  rt_dmz_id           = module.vpc_base.rt_dmz_id
+  stack_item_fullname = var.stack_item_fullname
+  stack_item_label    = var.stack_item_label
+  vpc_id              = module.vpc_base.vpc_id
 }
 
 ## Configures routing
 resource "aws_route" "dmz-to-igw" {
   destination_cidr_block = "0.0.0.0/0"
-  gateway_id             = "${module.vpc_base.igw_id}"
-  route_table_id         = "${module.vpc_base.rt_dmz_id}"
+  gateway_id             = module.vpc_base.igw_id
+  route_table_id         = module.vpc_base.rt_dmz_id
 }
diff --git a/examples/prereqs/outputs.tf b/examples/prereqs/outputs.tf
index 1230042..c0bc86a 100644
--- a/examples/prereqs/outputs.tf
+++ b/examples/prereqs/outputs.tf
@@ -1,13 +1,13 @@
 # Output variables
 
 output "dmz_rt_id" {
-  value = "${module.vpc_base.rt_dmz_id}"
+  value = module.vpc_base.rt_dmz_id
 }
 
 output "dmz_subnet_ids" {
-  value = "${module.vpc_az.dmz_ids}"
+  value = module.vpc_az.dmz_ids
 }
 
 output "vpc_id" {
-  value = "${module.vpc_base.vpc_id}"
+  value = module.vpc_base.vpc_id
 }
diff --git a/examples/prereqs/variables.tf b/examples/prereqs/variables.tf
index 3c36449..6a886ef 100644
--- a/examples/prereqs/variables.tf
+++ b/examples/prereqs/variables.tf
@@ -1,13 +1,13 @@
 # Input variables
 
 variable "region" {
-  type = "string"
+  type = string
 }
 
 variable "stack_item_fullname" {
-  type = "string"
+  type = string
 }
 
 variable "stack_item_label" {
-  type = "string"
+  type = string
 }