Terraform Resources

 

Table of contents

• Installing Terraform
  • Install Terraform on macOS
  • Install Terraform using Vagrant
• Build Infrastructure
  • Variable Configuration
  • Configuration File
• Change Infrastructure
• Destroy Infrastructure
• Resource Dependencies
• Useful Commands

 

Install Terraform on macOS

The easiest and quickest way to install Terraform is using Homebrew.

brew install terraform

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Build Infrastructure

You can find the latest Ubuntu AMI by going to their Amazon EC2 AMI Locator page

  or  

 

Variable Configuration

1. Copy and paste the following text to file named: terraform.tfvars

AWS_ACCESS_KEY="..."
AWS_SECRET_KEY="..."

Make sure you replace ... three dots with your credentials from AWS console.

Configuration File

2. Copy and paste the following text below to file named: terraform.code.tf

# ************************
# vars.tf
# ************************
 
variable "AWS_ACCESS_KEY" {}
variable "AWS_SECRET_KEY" {}
variable "AWS_REGION" {
  default = "us-east-1"
}
variable "AMIS" {
  type = "map"
  default = {
    # *******************************************
    # https://cloud-images.ubuntu.com/locator/ec2/
    #
    #   N. Virginia => us-east-1
    #   OS        => UBUNTU Xenial 16.04 LTS
    #   AMI_ID    => ami-245f7fcf
    #
    #   AMI shortcut (AMAZON MACHINE IMAGE)
    #
    # *******************************************
    us-east-1 = "ami-035be7bafff33b6b6"
  }
}
 
# ************************
# provider.tf
# ************************
provider "aws" {
    access_key = "${var.AWS_ACCESS_KEY}"
    secret_key = "${var.AWS_SECRET_KEY}"
    region = "${var.AWS_REGION}"
}
 
 
# ************************
# instance.tf
# ************************
resource "aws_instance" "SELENIUM" {
  ami = "${lookup(var.AMIS, var.AWS_REGION)}"
  tags { Name = "SELENIUM" }
  instance_type = "t2.micro"
  provisioner "local-exec" {
     command = "echo ${aws_instance.SELENIUM.private_ip} >> private_ips.txt"
  }
}
output "ip" {
    value = "${aws_instance.SELENIUM.public_ip}"
}

3. Verify these two files exit in your current directory:

• terraform.tfvars
• terraform.code.tf

4. Now you can run:

$ terraform init

Output after running terraform init

Initializing provider plugins...

$ terraform apply

Output after running terraform apply

Terraform will perform the following actions:
......

Do you want to perform these actions?
  Terraform will perform the actions described above.
  Only 'yes' will be accepted to approve.

  Enter a value: yes
  
.....
aws_instance.SELENIUM: Still creating... (10s elapsed)
aws_instance.SELENIUM: Still creating... (20s elapsed)
aws_instance.SELENIUM: Still creating... (30s elapsed)
aws_instance.SELENIUM: Provisioning with 'local-exec'...
aws_instance.SELENIUM (local-exec): Executing: ["/bin/sh" "-c" "echo 172.31.17.214 >> private_ips.txt"]
aws_instance.SELENIUM: Creation complete after 32s (ID: i-068bceca356edec95)

Apply complete! Resources: 1 added, 0 changed, 0 destroyed.

5. Delete/destroy your instances:

$ terraform destroy

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Change Infrastructure

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Destroy Infrastructure

Resources can be destroyed using the terraform destroy command, which is similar to terraform apply but it behaves as if all of the resources have been removed from the configuration.

$ terraform destroy

Output after running terraform destroy

Terraform will perform the following actions:
- aws_instance.SELENIUM

Plan: 0 to add, 0 to change, 1 to destroy.

Do you really want to destroy all resources?
  Terraform will destroy all your managed infrastructure, as shown above.
  There is no undo. Only 'yes' will be accepted to confirm.

  Enter a value: yes

Destroy complete! Resources: 1 destroyed.

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Resource Dependencies

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Useful Commands

Commands	Description
$ terraform plan	plan
$ terraform apply	shortcut for plan & apply - avoid this in production
$ terraform plan -out out.terraform	terraform plan and write the plan to out file
$ terraform apply out.terraform	apply terraform plan using out file
$ terraform show	show current state
$ cat terraform.tfstate	show state in JSON format

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