Updated comments

Author: alfonsof

code/05-cluster-webserver/main.tf

@@ -6,7 +6,7 @@ provider "aws" {
 # Data source: query the list of availability zones
 data "aws_availability_zones" "all" {}
 
-# Create a Security Group for an EC2 instance 
+# Create a Security Group for an EC2 instance
 resource "aws_security_group" "instance" {
   name = "terraform-example-instance"
 

code/06-create-s3/outputs.tf

@@ -1,4 +1,4 @@
-# Output variable: S3 bucket name
+# Output variable: S3 bucket
 output "s3_bucket_arn" {
   value = "${aws_s3_bucket.terraform_state.arn}"
 }

code/08-file-layout-example/global/s3/main.tf

@@ -1,7 +1,9 @@
+# Configure the AWS provider
 provider "aws" {
   region = "eu-west-1"
 }
- 
+
+# Create a S3 bucket
 resource "aws_s3_bucket" "terraform_state" {
   bucket		  = "${var.bucket_name}"
 

code/08-file-layout-example/global/s3/outputs.tf

@@ -1,3 +1,4 @@
+# Output variable: S3 bucket
 output "s3_bucket_arn" {
   value = "${aws_s3_bucket.terraform_state.arn}"
 }

code/08-file-layout-example/global/s3/vars.tf

@@ -1,4 +1,5 @@
+# Input variable: S3 bucket name
 variable "bucket_name" {
   description = "The name of the S3 bucket. Must be globally unique."
-  default = "terraform-state-afb"
+  default = "terraform-state-my-bucket"
 }

code/08-file-layout-example/stage/data-stores/mysql/backend.tf

@@ -1,7 +1,8 @@
-output "address" {
-  value = "${aws_db_instance.example.address}"
-}
-
-output "port" {
-  value = "${aws_db_instance.example.port}"
+# Define Terraform backend using a S3 bucket for storing the Terraform state
+terraform {
+  backend "s3" {
+    bucket = "terraform-state-my-bucket"
+    key = "file-layout/stage/data-stores/mysql/terraform.tfstate"
+    region = "eu-west-1"
+ }
 }

code/08-file-layout-example/stage/data-stores/mysql/main.tf

@@ -1,7 +1,9 @@
+# Configure the AWS provider
 provider "aws" {
   region = "eu-west-1"
 }
 
+# Create a DB instance
 resource "aws_db_instance" "example" {
   engine              = "mysql"
   allocated_storage   = 10

code/08-file-layout-example/stage/data-stores/mysql/outputs.tf

@@ -1,7 +1,9 @@
+# Output variable: DB instance address
 output "address" {
   value = "${aws_db_instance.example.address}"
 }
 
+# Output variable: DB instance port
 output "port" {
   value = "${aws_db_instance.example.port}"
 }

code/08-file-layout-example/stage/data-stores/mysql/vars.tf

@@ -1,7 +1,4 @@
-output "address" {
-  value = "${aws_db_instance.example.address}"
-}
-
-output "port" {
-  value = "${aws_db_instance.example.port}"
-}
+# Input variable: DB password
+variable "db_password" {
+  description = "The password for the database"
+}

code/08-file-layout-example/stage/services/webserver-cluster/backend.tf

@@ -1,7 +1,7 @@
 terraform {
   backend "s3" {
-    bucket = "terraform-state-afb"
-    key = "file-layout-example/stage/services/webserver-cluster/terraform.tfstate"
-    region = "eu-west-1"
+    bucket  = "terraform-state-my-bucket"
+    key     = "file-layout-example/stage/services/webserver-cluster/terraform.tfstate"
+    region  = "eu-west-1"
  }
 }

code/08-file-layout-example/stage/services/webserver-cluster/main.tf

@@ -1,9 +1,12 @@
+# Configure the AWS provider
 provider "aws" {
   region = "eu-west-1"
 }
- 
+
+# Data source: query the list of availability zones
 data "aws_availability_zones" "all" {}
 
+# Data source: DB remote state
 data "terraform_remote_state" "db" {
   backend = "s3"
 
@@ -14,23 +17,25 @@ data "terraform_remote_state" "db" {
   }
 }
 
+# Data source: Template file
 data "template_file" "user_data" {
   template = "${file("user-data.sh")}"
 
   vars {
     server_port = "${var.server_port}"
-    db_address = "${data.terraform_remote_state.db.address}"
-    db_port = "${data.terraform_remote_state.db.port}"
+    db_address  = "${data.terraform_remote_state.db.address}"
+    db_port     = "${data.terraform_remote_state.db.port}"
   }
 }
 
+# Create a Security Group for an EC2 instance
 resource "aws_security_group" "instance" {
   name = "terraform-example-instance"
 
   ingress {
-    from_port	= "${var.server_port}"
-    to_port		= "${var.server_port}"
-    protocol	= "tcp"
+    from_port	  = "${var.server_port}"
+    to_port		  = "${var.server_port}"
+    protocol	  = "tcp"
     cidr_blocks	= ["0.0.0.0/0"]
   }
 
@@ -39,26 +44,28 @@ resource "aws_security_group" "instance" {
   }
 }
 
+# Create a Security Group for an ELB
 resource "aws_security_group" "elb" {
   name = "terraform-example-elb"
 
   ingress {
     from_port	  = 80
-    to_port	  = 80
+    to_port	    = 80
     protocol	  = "tcp"
     cidr_blocks = ["0.0.0.0/0"]
   }
 
   egress {
     from_port	  = 0
-    to_port	  = 0
+    to_port	    = 0
     protocol	  = "-1"
     cidr_blocks = ["0.0.0.0/0"]
   }
 }
 
+# Create a Launch Configuration
 resource "aws_launch_configuration" "example" {
-  image_id	  = "ami-785db401"
+  image_id	      = "ami-785db401"
   instance_type   = "t2.micro"
   security_groups = ["${aws_security_group.instance.id}"]
   user_data       = "${data.template_file.user_data.rendered}"
@@ -68,6 +75,7 @@ resource "aws_launch_configuration" "example" {
   }
 }
 
+# Create an Autoscaling Group
 resource "aws_autoscaling_group" "example" {
   launch_configuration = "${aws_launch_configuration.example.id}"
   availability_zones   = ["${data.aws_availability_zones.all.names}"]
@@ -85,6 +93,7 @@ resource "aws_autoscaling_group" "example" {
   }
 }
 
+# Create an ELB
 resource "aws_elb" "example" {
   name               = "terraform-asg-example"
   availability_zones = ["${data.aws_availability_zones.all.names}"]
@@ -105,4 +114,3 @@ resource "aws_elb" "example" {
     target              = "HTTP:${var.server_port}/"
   }
 }
-

code/08-file-layout-example/stage/services/webserver-cluster/outputs.tf

@@ -1,3 +1,4 @@
+# Output variable: DNS Name of ELB
 output "elb_dns_name" {
   value = "${aws_elb.example.dns_name}"
 }

code/08-file-layout-example/stage/services/webserver-cluster/vars.tf

@@ -1,13 +1,16 @@
+# Input variable: server port
 variable "server_port" {
   description = "The port the server will use for HTTP requests"
-  default = "8080"
+  default     = "8080"
 }
 
+# Input variable: DB remote state bucket name
 variable "db_remote_state_bucket" {
   description = "The name of the S3 bucket used for the database's remote state storage"
-  default     =  "terraform-state-afb"
+  default     =  "terraform-state-my-bucket"
 }
 
+# Input variable: DB remote state bucket key
 variable "db_remote_state_key" {
   description = "The name of the key in the S3 bucket used for the database's remote state storage"
   default     = "file-layout-example/stage/data-stores/mysql/terraform.tfstate"