Terraform Command Basics¶

Link to Terraform Configuration Files¶

Step-01: Introduction¶

• Install Terraform
• Understand what is Terraform
• Understand Terrafom basic / essential commands
• terraform version
• terraform init
• terraform plan
• terraform validate
• terraform apply
• terraform show
• terraform refresh
• terraform providers
• terraform destroy

Azure Kubernetes Service with Azure DevOps and Terraform¶

Pre-requisite-1: Install Visual Studio Code (VS Code Editor)¶

• Download Visual Studio Code

Pre-requisite-2: Install HashiCorp Terraform plugin for VS Code¶

• Install Terraform Plugin for VS Code

Step-02: Terraform Install¶

• Referene Link:
• Download Terraform
• Install Terraform

MAC OS¶

# Install on MAC OS
brew install hashicorp/tap/terraform

# Verify Terraform Version
terraform version

# To Upgrade on MAC OS
brew upgrade hashicorp/tap/terraform

# Verify Terraform Version
terraform version

# Verify Installation
terraform help
terraform help plan

# Enable Tab Completion
terraform -install-autocomplete

Step-03: Install Azure CLI¶

# AZ CLI Current Version (if installed)
az --version

# Install Azure CLI (if not installed)
brew update && brew install azure-cli

# Upgrade az cli version
az --version
brew upgrade azure-cli 
[or]
az upgrade
az --version

# Azure CLI Login
az login

# List Subscriptions
az account list

# Set Specific Subscription (if we have multiple subscriptions)
az account set --subscription="SUBSCRIPTION_ID"

Step-04: Understand terrafrom init & provider azurerm¶

• Understand about Terraform Providers
• Understand about azurerm terraform provider, version and features
• terraform init: Initialize a Terraform working directory
• terraform apply: Builds or changes infrastructure

  # Change Directory to v1 folder
  cd v1-terraform-azurerm-provider
  
  # Initialize Terraform
  terraform init
  
  # Explore ".terraform" folder
  cd .terraform
  Go inside folders and review (.terraform/plugins/registry.terraform.io/hashicorp/azurerm/2.35.0/darwin_amd64)
  
  # Execute terraform apply
  terraform apply 
  ls -lrta
  discuss about "terraform.tfstate"
  
  # Delete .terraform folder (Understand what happens)
  rm -rf .terraform 
  terraform apply (Should say could not load plugin)
  To fix execute "terraform init" 
  
  # Clean-Up V1 folder
  rm terraform.tfstate
  ls -lrta
  

Step-04: Understand terraform plan, apply & Create Azure Resource Group¶

• Authenticate to Azure using Azure CLI az login
• Understand about terraform plan
• Understand about terraform apply
• Create Azure Resource Group using Terraform
• terraform init: Initialize a Terraform working directory
• terraform plan: Generate and show an execution plan
• terraform apply: Builds or changes infrastructure

  # Change Directory to v2 folder
  cd ../
  cd v2-terraform-azurerm-resource-group
  
  # Initialize Terraform
  terraform init
  
  # Validate terraform templates
  terraform validate
  
  # Dry run to see what resources gets created
  terraform plan
  
  # Create Resource Group in Azure
  terraform apply
  

• Verify if resource group created in Azure using Management Console

Step-05: Make changes to Resource Group and Deploy¶

• Add tags to Resource Group as below

  # Create a Azure Resource Group
  resource "azurerm_resource_group" "aksdev" {
    name     = "aks-rg2-tf"
    location = "Central US"
  
  # Add Tags
    tags = {
      "environment" = "k8sdev"
    }
  }
  

• Run terraform plan and apply

  # Dry run to see what resources gets created
  terraform plan
  
  # Create Resource Group in Azure
  terraform apply
  

• Verify if resource group created in Azure using Management Console

Step-06: Modify Resource Group Name and Understand what happens¶

• Change Resource Group name from aks-rg2-tf to aks-rg2-tf2 in main.tf

  # Understand what happens with this change
  terraform plan
  
  # Apply changes
  terraform apply
  

• Verify if resource group with new name got re-created in Azure using Management Console

Step-07: Understand terraform refresh in detail¶

• terraform refresh: Update local state file against real resources in cloud
• Desired State: Local Terraform Manifest (main.tf)
• Current State: Real Resources present in your cloud
• Command Order of Execution: refresh, plan, make a decision, apply
• Why? Lets understand that in detail about this order of execution

Step-07-01: Add a new tag to Resource Group using Azure Portal Management console¶

demotag: refreshtest

Step-07-02: Execute terraform plan¶

• You should observe no changes to local state file because plan does the comparison in memory
• no update to tfstate file locally about the change

  # Execute Terraform plan
  terraform plan 
  

Step-07-03: Execute terraform refresh¶

• You should see local state file updated with new demo tag

  # Execute terraform refresh
  ls -lrta
  terraform refresh
  diff terraform.tfstate.backup terraform.tfstate
  

Step-07-04: Why you need to the execution in this order (refresh, plan, make a decision, apply) ?¶

• There are changes happened in your infra manually and not via terraform.
• Now decision to be made if you want those changes or not.
• Choice-1: If you dont want those changes proceed with terraform apply so manual changes will be removed.
• Choice-2: If you want those changes, refer terraform.tfstate file about changes and embed them in your terraform manifests (example: main.tf) and proceed with flow (referesh, plan, review execution plan and apply)

Step-07-05: I picked choice-2, so i will update the tags in main.tf¶

• Update in main.tf

    tags = {
      "environment" = "k8sdev"
      "demotag"     = "refreshtest"
    }
  

Step-07-06: Execute the commands to make our manual change official in terraform manifests and tfstate files perspective¶

# Execute commands
ls -lrta
terraform refresh
diff terraform.tfstate.backup terraform.tfstate
terraform plan
terraform apply

Step-08: Understand terraform show, providers¶

• terraform show: Inspect Terraform state or plan
• terraform providers: Prints a tree of the providers used in the configuration

  # Terraform Show
  terraform show
  
  # Terraform Providers
  terraform providers
  

Step-09: Understand terraform destroy¶

• Understand about terraform destroy

  # Delete newly created Resource Group in Azure 
  terraform destroy
  
  # Delete State (Deleting for github repo case for course purpose)
  rm -rf .terraform
  rm -rf terraform.tfstate
  

References¶

• Main Azure Resource Manager Reference
• Azure Get Started on Terraform
• Terraform Resources and Modules

Best Selling Azure Kubernetes Service Course on Udemy¶

Best Selling AWS EKS Kubernetes Course on Udemy¶

HashiCorp Certified Terraform Associate - 50 Practical Demos¶