21 - Terraform Lab - By Houssem Dellai

 TERRAFORM - BY HOUSSEM DELLAI

•  Install Terraform - Chocolatey on Windows
• https://learn.hashicorp.com/tutorials/terraform/install-cli
• https://terraform.io
• Download Azure CLI
• https://docs.microsoft.com/en-us/cli/azure/install-azure-cli-windows?tabs=azure-cli
• Create an Azure Account
• Download Visual Studio Code 
• https://code.visualstudio.com/download
• Install Terraform Extension
• Download Source Code/ Template 
• https://github.com/HoussemDellai/terraform-course

Deploy Infra in the Cloud using Terraform

01 - Resource Group

vi main.tf
# valid for terraform version 0.13
# provider "azurerm" {
#   version = "=2.40.0"
#   features {}
# }

# valid for terraform version 0.14
provider "azurerm" {
  features {}
}

terraform {
  required_providers {
azurerm = {
  source  = "hashicorp/azurerm"
  version = "2.40.0"
}
  }
}

resource "azurerm_resource_group" "rg" {
  name     = "myFirstResourceGroup"
  location = "westeurope"
}

   Commands 
   # Login to Azure Cloud
   $ az login --use-device-code

   # get terraform version
  terraform version

   # get terraform commands
   terraform

   # init terraform's Azure provider (main.tf)
   terraform init

   # plan and preview terraform changes
   terraform plan

   # deploy terraform infra
   terraform apply

   # destroy infra
   terraform destroy

   # validate syntax

   terraform validate

   # Formatting codes

   terraform fmt

02 - Web App

       ** tranaform upgrade from 2.36 to 2.40

terraform init -upgrade

** create variable file 

=> variables.tf

variable "resource_group_name" {

default = "example-resource"

type = string

description = "RG name in Azure"

}

variable "resource_group_location" {

default = "West Europe"

type = string

description = "RG location in Azure"

}

variable "app_serevice_plan_name" {

default = "example-appserviceplan"

type = string

description = "Ap Service in Azure"

}

** modify main.tf

resource "azurerm_resource_group" "example" {

  name     = var.resource_group_name

  location = var.resource_group_location

.....

.....

- Overriding variable with .tfvars

  

  ** Another way to define variables

  => terraform.tfvars

resource_group_name     = "example-resource"

resource_group_location = "West Europe"

app_serevice_plan_name  = "example-appserviceplan"

app_service_name        = "terraform-demo"

- Output variables

  

  => output.tf

  output "webapp_url" {

    value = azurerm_app_service.example.default_site_hostname

  }

  output "webapp_ips" {

    value = azurerm_app_service.example.outbound_ip_addresses

  }

03 - Execution Plan

# plan and save the infra changes into tfplan file

terraform plan -out tfplan

# show the tfplan file

terraform show -json tfplan

terraform show -json tfplan >> tfplan.json

# apply the infra changes

terraform apply tfplan

# delete the infra

terraform destroy

  terraform init  ---->   terraform plan  ----> teraform apply

     main.tf                      .tfplan                     .tfstate

                            (changes)              (current state)

 

Terraform State -> when working as a team and every developer working on local machines and own tfstate file. it will start conflict if working same project with own tfstate file.

   

Solution => Centralized location of tfstate file and every developer access same file.

Lock this file during implementation apply

   How => 1. Create Resource Group

          2. Create Storage Account 

- RG name = terraform-rg

- Storage name = terraformrg

- location = Central US

- Peformance = standard 

Storage V2 -> Locally-redundant

  3. Go to Storage Account

Add - Containers

-> tfstate

 

4. create backend.tf file

terraform {

  backend "azurerm" {

resource_group_name   = "terraform-rg"

storage_account_name  = "terraformrg"

container_name  = "tfstate"

key  = "terraform.tfstate"

  }

}

5. terraform apply

    Acquiring state lock. This may take a few moments

- Deploy container service  ( AKS )

# plan and save the infra changes into tfplan file

terraform plan -out tfplan

# show the tfplan file

terraform show -json tfplan

terraform show -json tfplan >> tfplan.json

# show only the changes

cat tfplan.json | jq -r '(.resource_changes[] | [.change.actions[], .type, .change.after.name]) | @tsv'

cat tfplan.json | jq '[.resource_changes[] | {type: .type, name: .change.after.name, actions: .change.actions[]}]' 

# apply the infra changes

terraform apply tfplan

# delete the infra

terraform destroy

# cleanup files

rm terraform.tfstate

rm terraform.tfstate.backup

rm .terraform.lock.hcl

rm tfplan

rm tfplan.json

rm -r .terraform/