Lab Instructions

• A HTML version with code snippets that you can copy is available at https://govtechstacksg.github.io/stackx2019-terraform-basics/

• Login to your workstation

  Cloud9 URL:	https://user#.stackx.govtechstack.sg/ide.html
  User ID:	user#
  Password:	password#
  Git URL:	https://github.com/GovTechStackSG/stackx2019-terraform-basics

  To create a local copy of this git repository, run the following command in your Cloud9 environment.

  git clone https://github.com/GovTechStackSG/stackx2019-terraform-basics

• Create a basic Terraform configuration

  mkdir terraform101
  cd terraform101

  • Initialise your first terraform file - main.tf
  • Create provider block for AWS

  provider "aws" {
    #access_key = "PLEASE_NO_SECRETS_IN_YOUR_TF"
    #secret_key = "WHAT_DID_I_JUST_SAY"
    region     = "ap-southeast-1"
  }

• Initialize and apply the configuration (create infrastructure)

  • In the same Terraform configuration, main.tf , create an AWS instance with the ID web and the following:

    AMI ID:	ami-0fa08c0a6b3f80751
    Instance Type:	t2.micro
    Tags:	Name

    TIP: You need to start with a resource called aws_instance.

    resource "aws_instance" "web" {
      ami           = "ami-0fa08c0a6b3f80751"
      instance_type = "t2.micro"
    
      tags = {
        Name = "user#-HelloStackX"
      }
    }

  • You must run terraform init after adding or removing providers.

    terraform init        

  • Run terraform plan to see what will happen.

    terraform plan

  • Run terraform apply to create resources on AWS.

    terraform apply

  • Run terraform show to get details of the resources you created on AWS.

    terraform show

  • Define useful output values that will be highlighted to the user when Terraform applies: IP addresses, usernames, generated keys.

    output "public_ip" {
      value = "${aws_instance.web.public_ip}"
    }

  • Create a new output variable named "public_dns" which outputs the instance's public_dns attribute.

    output "public_dns" {
      value = "${aws_instance.web.public_dns}"
    }

  • Run terraform refresh to pick up the new output values.

    terraform refresh

  • Use the terraform output command to query for:

    • All outputs

      terraform output

    • A single output

      terraform output public_dns
      ping $(terraform output public_dns)

  • Define the parameterization of Terraform configurations, using variables. Create two variables in the Terraform configuration:

    • region (default: ap-southeast-1)

       variable "region" {
        type    = "string"
        default = "ap-southeast-1"
      }

    • label (no default value)

      variable "label" {
        type = "string"
      }

  • Variables' values can be interpolated into a string using the “${var.}” syntax

    resource "aws_instance" "web" {
      ami           = "ami-0b5a47f8865280111"
      instance_type = "t2.micro"
    
      tags = {
        Name = "${var.label}-HelloStackX"
        Creator = "Cameron Huysmans"
        TTL = "8"
      }
    }

  • Replace the hard-coded values in main.tf file with references to the newly-defined variables using the interpolation syntax.

      variable "region" {
        default = "ap-southeast-1"
      }
      variable "label" {
        default = "terraform101"
      }
      
      provider "aws" {
        region     = "${var.region}"
      }
    

  • Run terraform plan now that the variables are parameterized. Observe what happens.

• Change and re-apply the configuration