Table of contents

• Terraform
  • Terraform Basic
    • Terraform Blocks
      • Provider
      • Resource
      • Additional blocks
        • Input variables
        • local values
  • Installation
    • Window
  • Usage
    • GCP
    • Run your first terraform
  • Main terraform command

Terraform

HashiCorp Terraform is an open source infrastructure as code (IaC) software tool that allows Developer to provision infrastructure resources as a code.

Terraform Basics

Terraform file is end with .tf such as main.tf below

terraform {
  required_providers {
    google = {
      source = "hashicorp/google"
      version = "3.5.0"
    }
  }
}

provider "google" {
  credentials = file("<NAME>.json")

  project = "<PROJECT_ID>"
  region  = "us-central1"
  zone    = "us-central1-c"
}

resource "google_compute_network" "vpc_network" {
  name = "terraform-network"
}

Terraform Blocks

Terraform is consist of terraform {} that contain terraform setting required to provision your infrastructure.

terraform {
  required_providers {
    google = {
      source = "hashicorp/google"
      version = "3.5.0"
    }
  }
}

• For each, provider need the source variable to defines an optional hostname, a namespace, and the provider type which came from this Terraform Registry
• version is optional but you can also specify the version you satisfied with.

Provider

provider "google" {
  credentials = file("<NAME>.json")

  project = "<PROJECT_ID>"
  region  = "us-central1"
  zone    = "us-central1-c"
}

• The provider block configures the specified provider, in this repo we talked about gcp.
• you can also have multiple provider in one terraform such as aws, azure.

Resource

Use resource blocks to define components of your infrastructure. A resource might be a physical component such as a server, or it can be a logical resource such as a Heroku application.

resource "google_compute_network" "vpc_network" {
  name = "terraform-network"
}

In the code block we have:

• resource type: google_compute_network
• resource name: vpc_network
• The ID of network: google_compute_network.vpc_network

Additional blocks

this would be in variable.tf

Input variables

The variable block configures a single input variable for a Terraform module. Each block declares a single variable.

The name given in the block header is used to assign a value to the variable via the CLI and to reference the variable elsewhere in the configuration.

variable "region" {
    description = "Region for GCP resources. Choose as per your location: https://cloud.google.com/about/locations"
    default = "asia-southeast1"
    type = string
}

variable "images" {
  type = "map"

  default = {
    us-east-1 = "image-1234"
    us-west-2 = "image-4567"
  }
}

• type (Optional): can be defines to validate value
• default (Optional): the value must be provided by this field or on CLI while terraform is running.
• description (Optional): provide information about this variable

We can called these variable in main.tf with:

region = var.region
images = var.images

local values

A local value assigns a name to an expression, so you can use the name multiple times within a module instead of repeating the expression.

local {
    region= "asia-southeast1"
    zone = "asia-southeast1-a"
}

We can called these variable in main.tf with:

region = local.region
zone = local.zone

Installation

Window

1. you can download terraform from here
2. unzip and place somewhere in your system. let's say C:/terraform/
3. add C:/terraform/ to your path environment
4. open terminal
5. type terraform -version

Usage

GCP infrastructure

• Create main.tf file that contain terraform blocks as below. For other blocks you can specified how many service you want and what it's gonna look like. Example: my main.tf

terraform {
  required_version = ">= 1.0"
  backend "local" {}
  required_providers {
    google = {
      source  = "hashicorp/google"
    }
  }
}

• Set all your variable.tf the way you want. Example: my variable.tf

Run your first terraform!

• Running this command will download other plugin to connect with GCP to /terraform

terraform init

• Running this command will activate main.tf and create example of how your infrastructure look like!

terraform plan

• Running this command will apply everything that terraform plan tell you to your GCP project

terraform apply

• Running this command will destroy everything that terraform plan described and terraform apply created. So, please make sure to destroy it if you not gonna use it yet.

terraform destroy

note: If you follow my code in variable.tf project_id didn't defined. So you have to define it yourself in terminal when run something like terraform apply

Main commands:

• init Prepare your working directory for other commands
• validate Check whether the configuration is valid
• plan Show changes required by the current configuration
• apply Create or update infrastructure
• destroy Destroy previously-created infrastructure