diff --git a/aws_alb/main.tf b/aws_alb/main.tf
index 1f8b1b2..afc3b9a 100644
--- a/aws_alb/main.tf
+++ b/aws_alb/main.tf
@@ -1,61 +1,62 @@
 provider "aws" {
-  region = "${var.aws_region}"
+  region = var.aws_region
 }
 
-data "aws_availability_zones" "all" {}
+data "aws_availability_zones" "all" {
+}
 
 resource "aws_vpc" "default" {
   cidr_block           = "20.0.0.0/16"
   enable_dns_hostnames = true
 
-  tags {
+  tags = {
     Name = "hapee_test_vpc"
   }
 }
 
 resource "aws_subnet" "tf_test_subnet" {
-  count                   = "${var.aws_az_count}"
-  vpc_id                  = "${aws_vpc.default.id}"
-  cidr_block              = "${cidrsubnet(aws_vpc.default.cidr_block, 8, count.index)}"
-  availability_zone       = "${data.aws_availability_zones.all.names[count.index]}"
+  count                   = var.aws_az_count
+  vpc_id                  = aws_vpc.default.id
+  cidr_block              = cidrsubnet(aws_vpc.default.cidr_block, 8, count.index)
+  availability_zone       = data.aws_availability_zones.all.names[count.index]
   map_public_ip_on_launch = true
 
-  tags {
+  tags = {
     Name = "hapee_test_subnet"
   }
 }
 
 resource "aws_internet_gateway" "gw" {
-  vpc_id = "${aws_vpc.default.id}"
+  vpc_id = aws_vpc.default.id
 
-  tags {
+  tags = {
     Name = "hapee_test_ig"
   }
 }
 
 resource "aws_route_table" "r" {
-  vpc_id = "${aws_vpc.default.id}"
+  vpc_id = aws_vpc.default.id
 
   route {
     cidr_block = "0.0.0.0/0"
-    gateway_id = "${aws_internet_gateway.gw.id}"
+    gateway_id = aws_internet_gateway.gw.id
   }
 
-  tags {
+  tags = {
     Name = "aws_route_table"
   }
 }
 
 resource "aws_route_table_association" "a" {
-  count          = "${var.aws_az_count}"
-  subnet_id      = "${element(aws_subnet.tf_test_subnet.*.id, count.index)}"
-  route_table_id = "${aws_route_table.r.id}"
+  count          = var.aws_az_count
+  subnet_id      = element(aws_subnet.tf_test_subnet.*.id, count.index)
+  route_table_id = aws_route_table.r.id
 }
 
 resource "aws_security_group" "instance_sg1" {
   name        = "instance_sg1"
   description = "Instance (HAPEE/Web node) SG to pass tcp/22 by default"
-  vpc_id      = "${aws_vpc.default.id}"
+  vpc_id      = aws_vpc.default.id
 
   ingress {
     from_port   = 22
@@ -77,20 +78,20 @@ resource "aws_security_group" "instance_sg1" {
 resource "aws_security_group" "instance_sg2" {
   name        = "instance_sg2"
   description = "Instance (HAPEE/Web node) SG to pass ELB traffic  by default"
-  vpc_id      = "${aws_vpc.default.id}"
+  vpc_id      = aws_vpc.default.id
 
   ingress {
     from_port       = 80
     to_port         = 80
     protocol        = "tcp"
-    security_groups = ["${aws_security_group.instance_sg1.id}", "${aws_security_group.alb.id}"]
+    security_groups = [aws_security_group.instance_sg1.id, aws_security_group.alb.id]
   }
 
   ingress {
     from_port       = 8080
     to_port         = 8080
     protocol        = "tcp"
-    security_groups = ["${aws_security_group.instance_sg1.id}", "${aws_security_group.alb.id}"]
+    security_groups = [aws_security_group.instance_sg1.id, aws_security_group.alb.id]
   }
 }
 
@@ -98,7 +99,7 @@ resource "aws_security_group" "alb" {
   name        = "alb_sg"
   description = "Used in the terraform"
 
-  vpc_id = "${aws_vpc.default.id}"
+  vpc_id = aws_vpc.default.id
 
   ingress {
     from_port   = 80
@@ -114,7 +115,7 @@ resource "aws_security_group" "alb" {
     cidr_blocks = ["0.0.0.0/0"]
   }
 
-  depends_on = ["aws_internet_gateway.gw"]
+  depends_on = [aws_internet_gateway.gw]
 }
 
 resource "aws_lb" "hapee_alb" {
@@ -122,10 +123,10 @@ resource "aws_lb" "hapee_alb" {
 
   internal = false
 
-  subnets         = ["${aws_subnet.tf_test_subnet.*.id}"]
-  security_groups = ["${aws_security_group.alb.id}"]
+  subnets         = aws_subnet.tf_test_subnet.*.id
+  security_groups = [aws_security_group.alb.id]
 
-  tags {
+  tags = {
     Name = "hapee_alb"
   }
 }
@@ -133,7 +134,7 @@ resource "aws_lb" "hapee_alb" {
 resource "aws_lb_target_group" "hapee_alb_target" {
   name = "hapee-test-alb-tg"
 
-  vpc_id = "${aws_vpc.default.id}"
+  vpc_id = aws_vpc.default.id
 
   port     = 80
   protocol = "HTTP"
@@ -149,72 +150,88 @@ resource "aws_lb_target_group" "hapee_alb_target" {
     matcher             = "200,202"
   }
 
-  tags {
+  tags = {
     Name = "hapee_alb_tg"
   }
 }
 
 resource "aws_lb_listener" "hapee_alb_listener" {
-  load_balancer_arn = "${aws_lb.hapee_alb.arn}"
+  load_balancer_arn = aws_lb.hapee_alb.arn
 
   port     = 80
   protocol = "HTTP"
 
   default_action {
-    target_group_arn = "${aws_lb_target_group.hapee_alb_target.arn}"
+    target_group_arn = aws_lb_target_group.hapee_alb_target.arn
     type             = "forward"
   }
 }
 
 resource "aws_lb_target_group_attachment" "hapee_alb_target_att" {
-  count = "${var.hapee_cluster_size * var.aws_az_count}"
+  count = var.hapee_cluster_size * var.aws_az_count
 
-  target_group_arn = "${aws_lb_target_group.hapee_alb_target.arn}"
-  target_id        = "${element(aws_instance.hapee_node.*.id, count.index)}"
+  target_group_arn = aws_lb_target_group.hapee_alb_target.arn
+  target_id        = element(aws_instance.hapee_node.*.id, count.index)
 
   port = 80
 }
 
 resource "aws_instance" "web_node" {
-  count = "${var.web_cluster_size * var.aws_az_count}"
+  count = var.web_cluster_size * var.aws_az_count
 
-  instance_type = "${var.aws_web_instance_type}"
+  instance_type = var.aws_web_instance_type
 
-  ami = "${lookup(var.ubuntu_aws_amis, var.aws_region)}"
+  ami = var.ubuntu_aws_amis[var.aws_region]
 
-  key_name = "${var.key_name}"
+  key_name = var.key_name
 
-  vpc_security_group_ids = ["${aws_security_group.instance_sg1.id}", "${aws_security_group.instance_sg2.id}"]
-  subnet_id              = "${element(aws_subnet.tf_test_subnet.*.id, count.index / var.web_cluster_size)}"
-  user_data              = "${file("web-userdata.sh")}"
+  vpc_security_group_ids = [aws_security_group.instance_sg1.id, aws_security_group.instance_sg2.id]
+  subnet_id = element(
+    aws_subnet.tf_test_subnet.*.id,
+    //    count.index / var.web_cluster_size,
+    count.index
+  )
+  user_data = file("web-userdata.sh")
 
-  tags {
+  tags = {
     Name = "web_node_${count.index}"
   }
 }
 
 data "template_file" "hapee-userdata" {
-  template = "${file("hapee-userdata.sh.tpl")}"
+  template = file("hapee-userdata.sh.tpl")
 
-  vars {
-    serverlist = "${join("\n", formatlist("    server app-%v %v:80 cookie app-%v check", aws_instance.web_node.*.id, aws_instance.web_node.*.private_ip, aws_instance.web_node.*.id))}"
+  vars = {
+    serverlist = join(
+      "\n",
+      formatlist(
+        "    server app-%v %v:80 cookie app-%v check",
+        aws_instance.web_node.*.id,
+        aws_instance.web_node.*.private_ip,
+        aws_instance.web_node.*.id,
+      ),
+    )
   }
 }
 
 resource "aws_instance" "hapee_node" {
-  count = "${var.hapee_cluster_size * var.aws_az_count}"
+  count = var.hapee_cluster_size * var.aws_az_count
 
-  instance_type = "${var.aws_hapee_instance_type}"
+  instance_type = var.aws_hapee_instance_type
 
-  ami = "${lookup(var.hapee_aws_amis, var.aws_region)}"
+  ami = var.hapee_aws_amis[var.aws_region]
 
-  key_name = "${var.key_name}"
+  key_name = var.key_name
 
-  vpc_security_group_ids = ["${aws_security_group.instance_sg1.id}", "${aws_security_group.instance_sg2.id}"]
-  subnet_id              = "${element(aws_subnet.tf_test_subnet.*.id, count.index / var.hapee_cluster_size)}"
-  user_data              = "${data.template_file.hapee-userdata.rendered}"
+  vpc_security_group_ids = [aws_security_group.instance_sg1.id, aws_security_group.instance_sg2.id]
+  subnet_id = element(
+    aws_subnet.tf_test_subnet.*.id,
+    //  count.index / var.hapee_cluster_size,
+    count.index,
+  )
+  user_data = data.template_file.hapee-userdata.rendered
 
-  tags {
+  tags = {
     Name = "hapee_node_${count.index}"
   }
 }
diff --git a/aws_alb/outputs.tf b/aws_alb/outputs.tf
index f7851c1..e6bab7f 100644
--- a/aws_alb/outputs.tf
+++ b/aws_alb/outputs.tf
@@ -1,23 +1,49 @@
-output "AWS availability zones in use" {
-  value = "${aws_subnet.tf_test_subnet.*.availability_zone}"
+output "aws_availability_zones_in_use" {
+  description = "AWS availability zones in use"
+  value       = aws_subnet.tf_test_subnet.*.availability_zone
 }
 
-output "HAPEE nodes" {
-  value = "${formatlist("%s, private IP: %s, public IP: %s, AZ: %s", aws_instance.hapee_node.*.id, aws_instance.hapee_node.*.private_ip, aws_instance.hapee_node.*.public_ip, aws_instance.hapee_node.*.availability_zone)}"
+output "hapee_nodes" {
+  description = "HAPEE nodes"
+  value = formatlist(
+    "%s, private IP: %s, public IP: %s, AZ: %s",
+    aws_instance.hapee_node.*.id,
+    aws_instance.hapee_node.*.private_ip,
+    aws_instance.hapee_node.*.public_ip,
+    aws_instance.hapee_node.*.availability_zone,
+  )
 }
 
-output "Web node private IPs" {
-  value = "${formatlist("%s, private IP: %s, public IP: %s, AZ: %s", aws_instance.web_node.*.id, aws_instance.web_node.*.private_ip, aws_instance.web_node.*.public_ip, aws_instance.web_node.*.availability_zone)}"
+output "web_node_private_ips" {
+  description = "Web node private IPs"
+  value = formatlist(
+    "%s, private IP: %s, public IP: %s, AZ: %s",
+    aws_instance.web_node.*.id,
+    aws_instance.web_node.*.private_ip,
+    aws_instance.web_node.*.public_ip,
+    aws_instance.web_node.*.availability_zone,
+  )
 }
 
-output "ALB DNS address" {
-  value = "${aws_lb.hapee_alb.dns_name}"
+output "alb_dns_address" {
+  description = "ALB DNS address"
+  value       = aws_lb.hapee_alb.dns_name
 }
 
-output "ALB target group" {
-  value = "${aws_instance.hapee_node.*.id}"
+output "alb_target_group" {
+  description = "ALB target group"
+  value       = aws_instance.hapee_node.*.id
 }
 
-output "HAPEE backend server list" {
-  value = "${join("\n", formatlist("    server app-%v %v:80 cookie app-%v check", aws_instance.web_node.*.id, aws_instance.web_node.*.private_ip, aws_instance.web_node.*.id))}"
+output "hapee_backend_server_list" {
+  description = "HAPEE backend server list"
+  value = join(
+    "\n",
+    formatlist(
+      "    server app-%v %v:80 cookie app-%v check",
+      aws_instance.web_node.*.id,
+      aws_instance.web_node.*.private_ip,
+      aws_instance.web_node.*.id,
+    ),
+  )
 }
diff --git a/aws_alb/variables.tf b/aws_alb/variables.tf
index 6460b34..a44037f 100644
--- a/aws_alb/variables.tf
+++ b/aws_alb/variables.tf
@@ -1,35 +1,42 @@
 variable "aws_region" {
   description = "Home AWS region"
+  type        = string
   default     = "us-east-1"
 }
 
 variable "aws_az_count" {
   description = "Number of AZs to cover in a given AWS region"
-  default     = "2"
+  type        = number
+  default     = 2
 }
 
 variable "aws_hapee_instance_type" {
   description = "Default AWS instance type for HAPEE nodes"
+  type        = string
   default     = "t3.small"
 }
 
 variable "aws_web_instance_type" {
   description = "Default AWS instance type for Web nodes"
+  type        = string
   default     = "t3.small"
 }
 
 variable "key_name" {
   description = "SSH key pair to use in AWS"
+  type        = string
   default     = "hapee-test"
 }
 
 variable "hapee_cluster_size" {
   description = "Size of HAPEE nodes cluster"
+  type        = number
   default     = 2
 }
 
 variable "web_cluster_size" {
   description = "Size of Web nodes cluster"
+  type        = number
   default     = 3
 }
 
diff --git a/aws_alb/versions.tf b/aws_alb/versions.tf
new file mode 100644
index 0000000..d9b6f79
--- /dev/null
+++ b/aws_alb/versions.tf
@@ -0,0 +1,3 @@
+terraform {
+  required_version = ">= 0.12"
+}
diff --git a/aws_elb/main.tf b/aws_elb/main.tf
index 1ec3d84..cddc2bb 100644
--- a/aws_elb/main.tf
+++ b/aws_elb/main.tf
@@ -1,56 +1,56 @@
 provider "aws" {
-  region = "${var.aws_region}"
+  region = var.aws_region
 }
 
 resource "aws_vpc" "default" {
   cidr_block           = "20.0.0.0/16"
   enable_dns_hostnames = true
 
-  tags {
+  tags = {
     Name = "hapee_test_vpc"
   }
 }
 
 resource "aws_subnet" "tf_test_subnet" {
-  vpc_id                  = "${aws_vpc.default.id}"
+  vpc_id                  = aws_vpc.default.id
   cidr_block              = "20.0.0.0/24"
   map_public_ip_on_launch = true
 
-  tags {
+  tags = {
     Name = "hapee_test_subnet"
   }
 }
 
 resource "aws_internet_gateway" "gw" {
-  vpc_id = "${aws_vpc.default.id}"
+  vpc_id = aws_vpc.default.id
 
-  tags {
+  tags = {
     Name = "hapee_test_ig"
   }
 }
 
 resource "aws_route_table" "r" {
-  vpc_id = "${aws_vpc.default.id}"
+  vpc_id = aws_vpc.default.id
 
   route {
     cidr_block = "0.0.0.0/0"
-    gateway_id = "${aws_internet_gateway.gw.id}"
+    gateway_id = aws_internet_gateway.gw.id
   }
 
-  tags {
+  tags = {
     Name = "aws_route_table"
   }
 }
 
 resource "aws_route_table_association" "a" {
-  subnet_id      = "${aws_subnet.tf_test_subnet.id}"
-  route_table_id = "${aws_route_table.r.id}"
+  subnet_id      = aws_subnet.tf_test_subnet.id
+  route_table_id = aws_route_table.r.id
 }
 
 resource "aws_security_group" "instance_sg1" {
   name        = "instance_sg1"
   description = "Instance (HAPEE/Web node) SG to pass tcp/22 by default"
-  vpc_id      = "${aws_vpc.default.id}"
+  vpc_id      = aws_vpc.default.id
 
   ingress {
     from_port   = 22
@@ -72,20 +72,20 @@ resource "aws_security_group" "instance_sg1" {
 resource "aws_security_group" "instance_sg2" {
   name        = "instance_sg2"
   description = "Instance (HAPEE/Web node) SG to pass ELB traffic  by default"
-  vpc_id      = "${aws_vpc.default.id}"
+  vpc_id      = aws_vpc.default.id
 
   ingress {
     from_port       = 80
     to_port         = 80
     protocol        = "tcp"
-    security_groups = ["${aws_security_group.instance_sg1.id}", "${aws_security_group.elb.id}"]
+    security_groups = [aws_security_group.instance_sg1.id, aws_security_group.elb.id]
   }
 
   ingress {
     from_port       = 8080
     to_port         = 8080
     protocol        = "tcp"
-    security_groups = ["${aws_security_group.instance_sg1.id}", "${aws_security_group.elb.id}"]
+    security_groups = [aws_security_group.instance_sg1.id, aws_security_group.elb.id]
   }
 }
 
@@ -93,7 +93,7 @@ resource "aws_security_group" "elb" {
   name        = "elb_sg"
   description = "Used in the terraform"
 
-  vpc_id = "${aws_vpc.default.id}"
+  vpc_id = aws_vpc.default.id
 
   ingress {
     from_port   = 80
@@ -109,15 +109,15 @@ resource "aws_security_group" "elb" {
     cidr_blocks = ["0.0.0.0/0"]
   }
 
-  depends_on = ["aws_internet_gateway.gw"]
+  depends_on = [aws_internet_gateway.gw]
 }
 
 resource "aws_elb" "hapee_elb" {
   name = "hapee-test-elb"
 
-  subnets = ["${aws_subnet.tf_test_subnet.id}"]
+  subnets = [aws_subnet.tf_test_subnet.id]
 
-  security_groups = ["${aws_security_group.elb.id}"]
+  security_groups = [aws_security_group.elb.id]
 
   listener {
     instance_port     = 80
@@ -134,62 +134,70 @@ resource "aws_elb" "hapee_elb" {
     interval            = 30
   }
 
-  instances                   = ["${aws_instance.hapee_node.*.id}"]
+  instances                   = aws_instance.hapee_node.*.id
   cross_zone_load_balancing   = false
   idle_timeout                = 400
   connection_draining         = true
   connection_draining_timeout = 400
 
-  tags {
+  tags = {
     Name = "hapee_elb"
   }
 }
 
 resource "aws_proxy_protocol_policy" "proxy_http" {
-  load_balancer  = "${aws_elb.hapee_elb.name}"
+  load_balancer  = aws_elb.hapee_elb.name
   instance_ports = ["80"]
 }
 
 resource "aws_instance" "web_node" {
-  count = "${var.web_cluster_size}"
+  count = var.web_cluster_size
 
-  instance_type = "${var.aws_web_instance_type}"
+  instance_type = var.aws_web_instance_type
 
-  ami = "${lookup(var.ubuntu_aws_amis, var.aws_region)}"
+  ami = var.ubuntu_aws_amis[var.aws_region]
 
-  key_name = "${var.key_name}"
+  key_name = var.key_name
 
-  vpc_security_group_ids = ["${aws_security_group.instance_sg1.id}", "${aws_security_group.instance_sg2.id}"]
-  subnet_id              = "${aws_subnet.tf_test_subnet.id}"
-  user_data              = "${file("web-userdata.sh")}"
+  vpc_security_group_ids = [aws_security_group.instance_sg1.id, aws_security_group.instance_sg2.id]
+  subnet_id              = aws_subnet.tf_test_subnet.id
+  user_data              = file("web-userdata.sh")
 
-  tags {
+  tags = {
     Name = "web_node_${count.index}"
   }
 }
 
 data "template_file" "hapee-userdata" {
-  template = "${file("hapee-userdata.sh.tpl")}"
-
-  vars {
-    serverlist = "${join("\n", formatlist("    server app-%v %v:80 cookie app-%v check", aws_instance.web_node.*.id, aws_instance.web_node.*.private_ip, aws_instance.web_node.*.id))}"
+  template = file("hapee-userdata.sh.tpl")
+
+  vars = {
+    serverlist = join(
+      "\n",
+      formatlist(
+        "    server app-%v %v:80 cookie app-%v check",
+        aws_instance.web_node.*.id,
+        aws_instance.web_node.*.private_ip,
+        aws_instance.web_node.*.id,
+      ),
+    )
   }
 }
 
 resource "aws_instance" "hapee_node" {
-  count = "${var.hapee_cluster_size}"
+  count = var.hapee_cluster_size
 
-  instance_type = "${var.aws_hapee_instance_type}"
+  instance_type = var.aws_hapee_instance_type
 
-  ami = "${lookup(var.hapee_aws_amis, var.aws_region)}"
+  ami = var.hapee_aws_amis[var.aws_region]
 
-  key_name = "${var.key_name}"
+  key_name = var.key_name
 
-  vpc_security_group_ids = ["${aws_security_group.instance_sg1.id}", "${aws_security_group.instance_sg2.id}"]
-  subnet_id              = "${aws_subnet.tf_test_subnet.id}"
-  user_data              = "${data.template_file.hapee-userdata.rendered}"
+  vpc_security_group_ids = [aws_security_group.instance_sg1.id, aws_security_group.instance_sg2.id]
+  subnet_id              = aws_subnet.tf_test_subnet.id
+  user_data              = data.template_file.hapee-userdata.rendered
 
-  tags {
+  tags = {
     Name = "hapee_node_${count.index}"
   }
 }
diff --git a/aws_elb/outputs.tf b/aws_elb/outputs.tf
index 8f5bf25..5c78cda 100644
--- a/aws_elb/outputs.tf
+++ b/aws_elb/outputs.tf
@@ -1,19 +1,24 @@
-output "HAPEE nodes private IPs" {
-  value = "${aws_instance.hapee_node.*.private_ip}"
+output "hapee_node_private_ips" {
+  description = "HAPEE nodes private IPs"
+  value       = aws_instance.hapee_node.*.private_ip
 }
 
-output "HAPEE node public IPs" {
-  value = "${aws_instance.hapee_node.*.public_ip}"
+output "hapee_node_public_ips" {
+  description = "HAPEE nodes public IPs"
+  value       = aws_instance.hapee_node.*.public_ip
 }
 
-output "Web node private IPs" {
-  value = "${aws_instance.web_node.*.private_ip}"
+output "web_node_private_ips" {
+  description = "Web node private IPs"
+  value       = aws_instance.web_node.*.private_ip
 }
 
-output "Web node public IPs" {
-  value = "${aws_instance.web_node.*.public_ip}"
+output "web_node_public_ips" {
+  description = "Web node public IPs"
+  value       = aws_instance.web_node.*.public_ip
 }
 
-output "ELB DNS address" {
-  value = "${aws_elb.hapee_elb.dns_name}"
+output "elb_dns_address" {
+  description = "ELB DNS address"
+  value       = aws_elb.hapee_elb.dns_name
 }
diff --git a/aws_elb/variables.tf b/aws_elb/variables.tf
index abbb1fb..4840c7d 100644
--- a/aws_elb/variables.tf
+++ b/aws_elb/variables.tf
@@ -1,30 +1,36 @@
 variable "aws_region" {
   description = "Home AWS region"
+  type        = string
   default     = "us-east-1"
 }
 
 variable "aws_hapee_instance_type" {
   description = "Default AWS instance type for HAPEE nodes"
+  type        = string
   default     = "t3.small"
 }
 
 variable "aws_web_instance_type" {
   description = "Default AWS instance type for Web nodes"
+  type        = string
   default     = "t3.small"
 }
 
 variable "key_name" {
   description = "SSH key pair to use in AWS"
+  type        = string
   default     = "hapee-test"
 }
 
 variable "hapee_cluster_size" {
   description = "Size of HAPEE nodes cluster"
+  type        = number
   default     = 2
 }
 
 variable "web_cluster_size" {
   description = "Size of Web nodes cluster"
+  type        = number
   default     = 3
 }
 
diff --git a/aws_elb/versions.tf b/aws_elb/versions.tf
new file mode 100644
index 0000000..d9b6f79
--- /dev/null
+++ b/aws_elb/versions.tf
@@ -0,0 +1,3 @@
+terraform {
+  required_version = ">= 0.12"
+}
diff --git a/aws_heartbeat/main.tf b/aws_heartbeat/main.tf
index 996a580..24a5bea 100644
--- a/aws_heartbeat/main.tf
+++ b/aws_heartbeat/main.tf
@@ -4,24 +4,25 @@
 // file 'LICENSE.txt', which is part of this source code package.
 //
 provider "aws" {
-  region = "${var.aws_region}"
+  region = var.aws_region
 }
 
 // Lookup latest HAPEE AWS AMI (1.8r1 at this moment)
 data "aws_ami" "hapee_aws_amis" {
   most_recent = true
 
-  filter {
-    name   = "product-code"
-    values = ["483gxnuft87jy44d3q8n4kvt1"]
-  }
+  //  filter {
+  //    name   = "product-code"
+  //    values = ["483gxnuft87jy44d3q8n4kvt1"]
+  //  }
 
   filter {
     name   = "name"
     values = ["hapee-ubuntu-xenial-amd64-hvm-1.8*"]
   }
 
-  owners = ["aws-marketplace"]
+  # Source: 123832860963/hapee-ubuntu-xenial-amd64-hvm-1.8r1-20180516
+  owners = ["123832860963"]
 }
 
 // Lookup latest Ubuntu Xenial 16.04 AMI
@@ -41,56 +42,56 @@ resource "aws_vpc" "default" {
   cidr_block           = "20.0.0.0/16"
   enable_dns_hostnames = true
 
-  tags {
+  tags = {
     Name = "hapee_test_vpc"
   }
 }
 
 // Default subnet definition; in real world this sould span over at least two AZ
 resource "aws_subnet" "tf_test_subnet" {
-  vpc_id                  = "${aws_vpc.default.id}"
+  vpc_id                  = aws_vpc.default.id
   cidr_block              = "20.0.0.0/24"
   map_public_ip_on_launch = true
 
-  tags {
+  tags = {
     Name = "hapee_test_subnet"
   }
 }
 
 // Define our IGW
 resource "aws_internet_gateway" "gw" {
-  vpc_id = "${aws_vpc.default.id}"
+  vpc_id = aws_vpc.default.id
 
-  tags {
+  tags = {
     Name = "hapee_test_ig"
   }
 }
 
 // Define our standard routing table
 resource "aws_route_table" "r" {
-  vpc_id = "${aws_vpc.default.id}"
+  vpc_id = aws_vpc.default.id
 
   route {
     cidr_block = "0.0.0.0/0"
-    gateway_id = "${aws_internet_gateway.gw.id}"
+    gateway_id = aws_internet_gateway.gw.id
   }
 
-  tags {
+  tags = {
     Name = "hapee_test_route_table"
   }
 }
 
 // Routing table association for default subnet
 resource "aws_route_table_association" "a" {
-  subnet_id      = "${aws_subnet.tf_test_subnet.id}"
-  route_table_id = "${aws_route_table.r.id}"
+  subnet_id      = aws_subnet.tf_test_subnet.id
+  route_table_id = aws_route_table.r.id
 }
 
 // Security group for Web backends
 resource "aws_security_group" "web_node_sg" {
   name        = "web_node_sg"
   description = "Instance Web SG: pass SSH, permit HTTP only from HAPEE"
-  vpc_id      = "${aws_vpc.default.id}"
+  vpc_id      = aws_vpc.default.id
 
   ingress {
     from_port   = 22
@@ -104,7 +105,7 @@ resource "aws_security_group" "web_node_sg" {
     from_port       = 80
     to_port         = 80
     protocol        = "tcp"
-    security_groups = ["${aws_security_group.hapee_node_sg.id}"]
+    security_groups = [aws_security_group.hapee_node_sg.id]
   }
 
   egress {
@@ -115,7 +116,7 @@ resource "aws_security_group" "web_node_sg" {
     self        = true
   }
 
-  tags {
+  tags = {
     Name = "hapee_web_node_sg"
   }
 }
@@ -124,7 +125,7 @@ resource "aws_security_group" "web_node_sg" {
 resource "aws_security_group" "hapee_node_sg" {
   name        = "hapee_node_sg"
   description = "Instance HAPEE SG: pass SSH, HTTP, HTTPS and Dashboard traffic by default"
-  vpc_id      = "${aws_vpc.default.id}"
+  vpc_id      = aws_vpc.default.id
 
   ingress {
     from_port   = 3
@@ -189,7 +190,7 @@ resource "aws_security_group" "hapee_node_sg" {
     self        = true
   }
 
-  tags {
+  tags = {
     Name = "hapee_node_sg"
   }
 }
@@ -230,33 +231,33 @@ data "aws_iam_policy_document" "eip_policy" {
 // IAM role - EIP role
 resource "aws_iam_role" "eip_role" {
   name               = "hapee_eip_role"
-  assume_role_policy = "${data.aws_iam_policy_document.instance_assume_role_policy.json}"
+  assume_role_policy = data.aws_iam_policy_document.instance_assume_role_policy.json
 }
 
 // IAM role policy - EIP role policy
 resource "aws_iam_role_policy" "eip_role_policy" {
   name   = "hapee_eip_role_policy"
-  role   = "${aws_iam_role.eip_role.id}"
-  policy = "${data.aws_iam_policy_document.eip_policy.json}"
+  role   = aws_iam_role.eip_role.id
+  policy = data.aws_iam_policy_document.eip_policy.json
 }
 
 // IAM instance profile - EIP instance profile
 resource "aws_iam_instance_profile" "eip_instance_profile" {
   name = "hapee_instance_profile"
-  role = "${aws_iam_role.eip_role.id}"
+  role = aws_iam_role.eip_role.id
 }
 
 // Instance definition for Web backends
 // Variable instance count
 resource "aws_instance" "web_node" {
-  count = "${var.web_cluster_size}"
+  count = var.web_cluster_size
 
-  instance_type = "${var.aws_web_instance_type}"
-  ami           = "${data.aws_ami.ubuntu_aws_amis.id}"
-  key_name      = "${var.key_name}"
+  instance_type = var.aws_web_instance_type
+  ami           = data.aws_ami.ubuntu_aws_amis.id
+  key_name      = var.key_name
 
-  vpc_security_group_ids = ["${aws_security_group.web_node_sg.id}"]
-  subnet_id              = "${aws_subnet.tf_test_subnet.id}"
+  vpc_security_group_ids = [aws_security_group.web_node_sg.id]
+  subnet_id              = aws_subnet.tf_test_subnet.id
 
   user_data = <<EOF
   #cloud-config
@@ -264,9 +265,11 @@ resource "aws_instance" "web_node" {
     - systemctl stop apt-daily.service
     - systemctl kill --kill-who=all apt-daily.service
     - systemctl stop apt-daily.timer
-  EOF
+  
+EOF
+
 
-  tags {
+  tags = {
     Name = "hapee_web_node"
   }
 }
@@ -276,13 +279,13 @@ resource "aws_instance" "web_node" {
 resource "aws_instance" "hapee_node" {
   count = 2
 
-  instance_type        = "${var.aws_hapee_instance_type}"
-  ami                  = "${data.aws_ami.hapee_aws_amis.id}"
-  key_name             = "${var.key_name}"
-  iam_instance_profile = "${aws_iam_instance_profile.eip_instance_profile.id}"
+  instance_type        = var.aws_hapee_instance_type
+  ami                  = data.aws_ami.hapee_aws_amis.id
+  key_name             = var.key_name
+  iam_instance_profile = aws_iam_instance_profile.eip_instance_profile.id
 
-  vpc_security_group_ids = ["${aws_security_group.hapee_node_sg.id}"]
-  subnet_id              = "${aws_subnet.tf_test_subnet.id}"
+  vpc_security_group_ids = [aws_security_group.hapee_node_sg.id]
+  subnet_id              = aws_subnet.tf_test_subnet.id
 
   user_data = <<EOF
   #cloud-config
@@ -292,7 +295,7 @@ resource "aws_instance" "hapee_node" {
     - systemctl stop apt-daily.timer
   EOF
 
-  tags {
+  tags = {
     Name = "hapee_lb_node"
   }
 }
@@ -300,6 +303,6 @@ resource "aws_instance" "hapee_node" {
 // EIP allocation for primary static address for each HAPEE LB instance
 resource "aws_eip" "hapee_node_eip1" {
   count             = 2
-  network_interface = "${element(aws_instance.hapee_node.*.network_interface_id, count.index)}"
+  network_interface = element(aws_instance.hapee_node.*.network_interface_id, count.index)
   vpc               = true
 }
diff --git a/aws_heartbeat/outputs.tf b/aws_heartbeat/outputs.tf
index 64d5587..30d2649 100644
--- a/aws_heartbeat/outputs.tf
+++ b/aws_heartbeat/outputs.tf
@@ -1,23 +1,29 @@
-output "HAPEE nodes private IPs" {
-  value = "${aws_instance.hapee_node.*.private_ip}"
+output "hapee_nodes_private_ips" {
+  description = "HAPEE nodes private IPs"
+  value       = aws_instance.hapee_node.*.private_ip
 }
 
-output "HAPEE node EIP1 (primary interface) allocation IDs" {
-  value = "${aws_eip.hapee_node_eip1.*.id}"
+output "hapee_node_eip1_allocation_ids" {
+  description = "HAPEE node EIP1 (primary interface) allocation IDs"
+  value       = aws_eip.hapee_node_eip1.*.id
 }
 
-output "HAPEE node EIP1 (primary interface) public IPs" {
-  value = "${aws_eip.hapee_node_eip1.*.public_ip}"
+output "hapee_node_eip1_public_ips" {
+  description = "HAPEE node EIP1 (primary interface) public IPs"
+  value       = aws_eip.hapee_node_eip1.*.public_ip
 }
 
-output "HAPEE node primary interface IDs" {
-  value = "${aws_instance.hapee_node.*.network_interface_id}"
+output "hapee_node_primary_interface_ids" {
+  description = "HAPEE node primary interface IDs"
+  value       = aws_instance.hapee_node.*.primary_network_interface_id
 }
 
-output "Web node private IPs" {
-  value = "${aws_instance.web_node.*.private_ip}"
+output "web_node_private_ips" {
+  description = "Web node private IPs"
+  value       = aws_instance.web_node.*.private_ip
 }
 
-output "Web node public IPs" {
-  value = "${aws_instance.web_node.*.public_ip}"
+output "web_node_public_ips" {
+  description = "Web node public IPs"
+  value       = aws_instance.web_node.*.public_ip
 }
diff --git a/aws_heartbeat/variables.tf b/aws_heartbeat/variables.tf
index 31ed185..e3d0f98 100644
--- a/aws_heartbeat/variables.tf
+++ b/aws_heartbeat/variables.tf
@@ -1,29 +1,34 @@
 // Set default AWS region. Pay attention to inventory/ec2.ini which should also use the same region.
 variable "aws_region" {
   description = "Home AWS region"
+  type        = string
   default     = "us-east-1"
 }
 
 // Default instance type for HAPEE LB instances. Obviously, something along m5.xlarge or c5.xlarge should be a perfect fit.
 variable "aws_hapee_instance_type" {
   description = "Default AWS instance type for HAPEE nodes"
+  type        = string
   default     = "t3.small"
 }
 
 // Default instance type for Web backends. Typically m5.4xlarge and similar, depending on use case.
 variable "aws_web_instance_type" {
   description = "Default AWS instance type for Web nodes"
+  type        = string
   default     = "t3.small"
 }
 
 // SSH pub key pair located on Amazon. Also set/used in ansible.cfg.
 variable "key_name" {
   description = "SSH key pair to use in AWS"
+  type        = string
   default     = "noprod-hapee-test"
 }
 
 // Typical size of Web cluster backends. It's reasonable to have more than 2.
 variable "web_cluster_size" {
   description = "Size of Web nodes cluster"
+  type        = number
   default     = 3
 }
diff --git a/aws_heartbeat/versions.tf b/aws_heartbeat/versions.tf
new file mode 100644
index 0000000..d9b6f79
--- /dev/null
+++ b/aws_heartbeat/versions.tf
@@ -0,0 +1,3 @@
+terraform {
+  required_version = ">= 0.12"
+}
diff --git a/aws_keepalived/main.tf b/aws_keepalived/main.tf
index 13d3f55..9dd54aa 100644
--- a/aws_keepalived/main.tf
+++ b/aws_keepalived/main.tf
@@ -3,7 +3,7 @@
 // file 'LICENSE.txt', which is part of this source code package.
 //
 provider "aws" {
-  region = "${var.aws_region}"
+  region = var.aws_region
 }
 
 // Lookup latest HAPEE Ubuntu AMI (Ubuntu Bionic 18.04 + HAPEE 1.8r2 at this moment)
@@ -40,56 +40,56 @@ resource "aws_vpc" "default" {
   cidr_block           = "20.0.0.0/16"
   enable_dns_hostnames = true
 
-  tags {
+  tags = {
     Name = "hapee_test_vpc"
   }
 }
 
 // Default subnet definition; in real world this sould span over at least two AZ
 resource "aws_subnet" "tf_test_subnet" {
-  vpc_id                  = "${aws_vpc.default.id}"
+  vpc_id                  = aws_vpc.default.id
   cidr_block              = "20.0.0.0/24"
   map_public_ip_on_launch = true
 
-  tags {
+  tags = {
     Name = "hapee_test_subnet"
   }
 }
 
 // Define our IGW
 resource "aws_internet_gateway" "gw" {
-  vpc_id = "${aws_vpc.default.id}"
+  vpc_id = aws_vpc.default.id
 
-  tags {
+  tags = {
     Name = "hapee_test_ig"
   }
 }
 
 // Define our standard routing table
 resource "aws_route_table" "r" {
-  vpc_id = "${aws_vpc.default.id}"
+  vpc_id = aws_vpc.default.id
 
   route {
     cidr_block = "0.0.0.0/0"
-    gateway_id = "${aws_internet_gateway.gw.id}"
+    gateway_id = aws_internet_gateway.gw.id
   }
 
-  tags {
+  tags = {
     Name = "hapee_test_route_table"
   }
 }
 
 // Routing table association for default subnet
 resource "aws_route_table_association" "a" {
-  subnet_id      = "${aws_subnet.tf_test_subnet.id}"
-  route_table_id = "${aws_route_table.r.id}"
+  subnet_id      = aws_subnet.tf_test_subnet.id
+  route_table_id = aws_route_table.r.id
 }
 
 // Security group for Web backends
 resource "aws_security_group" "web_node_sg" {
   name        = "web_node_sg"
   description = "Instance Web SG: pass SSH, permit HTTP only from HAPEE"
-  vpc_id      = "${aws_vpc.default.id}"
+  vpc_id      = aws_vpc.default.id
 
   ingress {
     from_port   = 22
@@ -103,7 +103,7 @@ resource "aws_security_group" "web_node_sg" {
     from_port       = 80
     to_port         = 80
     protocol        = "tcp"
-    security_groups = ["${aws_security_group.hapee_node_sg.id}"]
+    security_groups = [aws_security_group.hapee_node_sg.id]
   }
 
   egress {
@@ -114,7 +114,7 @@ resource "aws_security_group" "web_node_sg" {
     self        = true
   }
 
-  tags {
+  tags = {
     Name = "hapee_web_node_sg"
   }
 }
@@ -123,7 +123,7 @@ resource "aws_security_group" "web_node_sg" {
 resource "aws_security_group" "hapee_node_sg" {
   name        = "hapee_node_sg"
   description = "Instance HAPEE SG: pass SSH, HTTP, HTTPS and Dashboard traffic by default"
-  vpc_id      = "${aws_vpc.default.id}"
+  vpc_id      = aws_vpc.default.id
 
   ingress {
     from_port   = 3
@@ -196,7 +196,7 @@ resource "aws_security_group" "hapee_node_sg" {
     self        = true
   }
 
-  tags {
+  tags = {
     Name = "hapee_node_sg"
   }
 }
@@ -237,33 +237,33 @@ data "aws_iam_policy_document" "eip_policy" {
 // IAM role - EIP role
 resource "aws_iam_role" "eip_role" {
   name               = "hapee_eip_role"
-  assume_role_policy = "${data.aws_iam_policy_document.instance_assume_role_policy.json}"
+  assume_role_policy = data.aws_iam_policy_document.instance_assume_role_policy.json
 }
 
 // IAM role policy - EIP role policy
 resource "aws_iam_role_policy" "eip_role_policy" {
   name   = "hapee_eip_role_policy"
-  role   = "${aws_iam_role.eip_role.id}"
-  policy = "${data.aws_iam_policy_document.eip_policy.json}"
+  role   = aws_iam_role.eip_role.id
+  policy = data.aws_iam_policy_document.eip_policy.json
 }
 
 // IAM instance profile - EIP instance profile
 resource "aws_iam_instance_profile" "eip_instance_profile" {
   name = "hapee_instance_profile"
-  role = "${aws_iam_role.eip_role.id}"
+  role = aws_iam_role.eip_role.id
 }
 
 // Instance definition for Web backends
 // Variable instance count
 resource "aws_instance" "web_node" {
-  count = "${var.web_cluster_size}"
+  count = var.web_cluster_size
 
-  instance_type = "${var.aws_web_instance_type}"
-  ami           = "${data.aws_ami.ubuntu_aws_amis.id}"
-  key_name      = "${var.key_name}"
+  instance_type = var.aws_web_instance_type
+  ami           = data.aws_ami.ubuntu_aws_amis.id
+  key_name      = var.key_name
 
-  vpc_security_group_ids = ["${aws_security_group.web_node_sg.id}"]
-  subnet_id              = "${aws_subnet.tf_test_subnet.id}"
+  vpc_security_group_ids = [aws_security_group.web_node_sg.id]
+  subnet_id              = aws_subnet.tf_test_subnet.id
 
   user_data = <<EOF
   #cloud-config
@@ -271,9 +271,11 @@ resource "aws_instance" "web_node" {
     - systemctl stop apt-daily.service
     - systemctl kill --kill-who=all apt-daily.service
     - systemctl stop apt-daily.timer
-  EOF
+  
+EOF
+
 
-  tags {
+  tags = {
     Name = "hapee_web_node"
   }
 }
@@ -283,13 +285,13 @@ resource "aws_instance" "web_node" {
 resource "aws_instance" "hapee_node" {
   count = 2
 
-  instance_type        = "${var.aws_hapee_instance_type}"
-  ami                  = "${data.aws_ami.hapee_aws_amis.id}"
-  key_name             = "${var.key_name}"
-  iam_instance_profile = "${aws_iam_instance_profile.eip_instance_profile.id}"
+  instance_type        = var.aws_hapee_instance_type
+  ami                  = data.aws_ami.hapee_aws_amis.id
+  key_name             = var.key_name
+  iam_instance_profile = aws_iam_instance_profile.eip_instance_profile.id
 
-  vpc_security_group_ids = ["${aws_security_group.hapee_node_sg.id}"]
-  subnet_id              = "${aws_subnet.tf_test_subnet.id}"
+  vpc_security_group_ids = [aws_security_group.hapee_node_sg.id]
+  subnet_id              = aws_subnet.tf_test_subnet.id
 
   user_data = <<EOF
   #cloud-config
@@ -300,14 +302,17 @@ resource "aws_instance" "hapee_node" {
     - systemctl stop apt-daily-upgrade.timer
   EOF
 
-  tags {
+  tags = {
     Name = "hapee_lb_node"
   }
 }
 
 // EIP allocation for primary static address for each HAPEE LB instance
 resource "aws_eip" "hapee_node_eip1" {
-  count             = 2
-  network_interface = "${element(aws_instance.hapee_node.*.primary_network_interface_id, count.index)}"
-  vpc               = true
+  count = 2
+  network_interface = element(
+    aws_instance.hapee_node.*.primary_network_interface_id,
+    count.index,
+  )
+  vpc = true
 }
diff --git a/aws_keepalived/outputs.tf b/aws_keepalived/outputs.tf
index f7078e2..30d2649 100644
--- a/aws_keepalived/outputs.tf
+++ b/aws_keepalived/outputs.tf
@@ -1,23 +1,29 @@
-output "HAPEE nodes private IPs" {
-  value = "${aws_instance.hapee_node.*.private_ip}"
+output "hapee_nodes_private_ips" {
+  description = "HAPEE nodes private IPs"
+  value       = aws_instance.hapee_node.*.private_ip
 }
 
-output "HAPEE node EIP1 (primary interface) allocation IDs" {
-  value = "${aws_eip.hapee_node_eip1.*.id}"
+output "hapee_node_eip1_allocation_ids" {
+  description = "HAPEE node EIP1 (primary interface) allocation IDs"
+  value       = aws_eip.hapee_node_eip1.*.id
 }
 
-output "HAPEE node EIP1 (primary interface) public IPs" {
-  value = "${aws_eip.hapee_node_eip1.*.public_ip}"
+output "hapee_node_eip1_public_ips" {
+  description = "HAPEE node EIP1 (primary interface) public IPs"
+  value       = aws_eip.hapee_node_eip1.*.public_ip
 }
 
-output "HAPEE node primary interface IDs" {
-  value = "${aws_instance.hapee_node.*.primary_network_interface_id}"
+output "hapee_node_primary_interface_ids" {
+  description = "HAPEE node primary interface IDs"
+  value       = aws_instance.hapee_node.*.primary_network_interface_id
 }
 
-output "Web node private IPs" {
-  value = "${aws_instance.web_node.*.private_ip}"
+output "web_node_private_ips" {
+  description = "Web node private IPs"
+  value       = aws_instance.web_node.*.private_ip
 }
 
-output "Web node public IPs" {
-  value = "${aws_instance.web_node.*.public_ip}"
+output "web_node_public_ips" {
+  description = "Web node public IPs"
+  value       = aws_instance.web_node.*.public_ip
 }
diff --git a/aws_keepalived/variables.tf b/aws_keepalived/variables.tf
index 31ed185..e3d0f98 100644
--- a/aws_keepalived/variables.tf
+++ b/aws_keepalived/variables.tf
@@ -1,29 +1,34 @@
 // Set default AWS region. Pay attention to inventory/ec2.ini which should also use the same region.
 variable "aws_region" {
   description = "Home AWS region"
+  type        = string
   default     = "us-east-1"
 }
 
 // Default instance type for HAPEE LB instances. Obviously, something along m5.xlarge or c5.xlarge should be a perfect fit.
 variable "aws_hapee_instance_type" {
   description = "Default AWS instance type for HAPEE nodes"
+  type        = string
   default     = "t3.small"
 }
 
 // Default instance type for Web backends. Typically m5.4xlarge and similar, depending on use case.
 variable "aws_web_instance_type" {
   description = "Default AWS instance type for Web nodes"
+  type        = string
   default     = "t3.small"
 }
 
 // SSH pub key pair located on Amazon. Also set/used in ansible.cfg.
 variable "key_name" {
   description = "SSH key pair to use in AWS"
+  type        = string
   default     = "noprod-hapee-test"
 }
 
 // Typical size of Web cluster backends. It's reasonable to have more than 2.
 variable "web_cluster_size" {
   description = "Size of Web nodes cluster"
+  type        = number
   default     = 3
 }
diff --git a/aws_keepalived/versions.tf b/aws_keepalived/versions.tf
new file mode 100644
index 0000000..d9b6f79
--- /dev/null
+++ b/aws_keepalived/versions.tf
@@ -0,0 +1,3 @@
+terraform {
+  required_version = ">= 0.12"
+}