Understand Terraform Language Basics¶

Link to Terraform Configuration Files ¶

Step-01: Introduction¶

Understand Terraform language basics
Understand Resources
Understand Blocks
Understand Arguments
Understand Identifiers
Understand Comments
Understand Input Variables in Terraform
Understand Output Values in Terraform
Migrate Terraform State from local to Remote Storage (Azure Storage)

Azure Kubernetes Service with Azure DevOps and Terraform¶

Step-02: Terraform Configuration Language Syntax¶

Understand Resources
Understand Blocks
Understand Arguments
Understand Identifiers
Understand Comments
Terraform Configuration

# Template
<BLOCK TYPE> "<BLOCK LABEL>" "<BLOCK LABEL>"   {
  # Block body
  <IDENTIFIER> = <EXPRESSION> # Argument
}

# Example
resource "azurerm_resource_group" "aksdev" {   # BLOCK
  name     = "aks-rg2-tf" # Argument
  location = var.region   # Argument with value as expression (Variable value replaced from varibales.tf )

  tags = {  #BLOCK
    "environment" = "k8sdev"
  }
}

Step-03: Define Terraform Providers¶

VS Code Terraform Plugin - Syntax highlighting and autocompletion for Terraform
Understand about Terraform Settings Block
We primarily define the below 3 items in Terraform Settings Block
Terraform Version
Terraform Providers
- Azure RM Provider
- Azure AD Provider
- Random Provider
- Append with /docs for above 3 links to get their equivalent documentation
Terraform State Storage Backend

Create a file 01-main.tf and create terraform providers

# Terraform Settings Block (https://www.terraform.io/docs/configuration/terraform.html)
terraform {
  # Use a recent version of Terraform
  required_version = ">= 0.13"

  # Map providers to thier sources, required in Terraform 13+
  required_providers {
    # Azure Resource Manager 2.x (Base Azure RM Module)
    azurerm = {
      source  = "hashicorp/azurerm"
      version = "~> 2.0"
    }
    # Azure Active Directory 1.x (required for AKS and Azure AD Integration)
    azuread = {
      source  = "hashicorp/azuread"
      version = "~> 1.0"
    }
    # Random 3.x (Required to generate random names for Log Analytics Workspace)
    random = {
      source  = "hashicorp/random"
      version = "~> 3.0"
    }
  }
# Configure Terraform State Storage
    backend "azurerm" {
    resource_group_name   = "terraform-storage-rg"
    storage_account_name  = "terraformstatexlrwdrzs"
    container_name        = "prodtfstate"
    key                   = "terraform.tfstate"
  }
}

Step-04: Define Azure Resource Manager Features Block¶

Add azurerm features block to 01-main.tf

# This block is required for azurerm 2.x
provider azurerm {
  # v2.x azurerm requires "features" block
  features {}
}

Step-05: Create Random Pet Resource¶

Create Random pet resource in 01-main.tf

# Create Random pet resource
resource "random_pet" "aksrandom" {}

Initialize the terraform and understand what happened
```
# Terraform Initialize
terraform init
```

Step-06: Create a Resource Group Resource¶

Create a file named 03-resource-group.tf

resource "azurerm_resource_group" "aks_rg" {
  location = "Central US"
  name     = "terraform-aks"
}

Step-07: Understand and Create Terraform Input Variables¶

Three types of Terraform Variables¶

Input Variables¶

We can parameterize our deployments using Terraform Input Variables.
This is the right way to build a Terraform project that can be reused to deploy multiple environments like dev, qa, staging and production
Implement input variables in terraform for AKS Cluster
Understand different options available to pass input variables
variables.tf
arguments during runtime (-var)
arguments during runtime (-var-file terraform.tfvars) with a file containing variables

Using 02-variables.tf¶

Define few input variables in 02-variables.tf
Reference them in 03-resource-group.tf
Variables we are going to play with
Resource Group Name
Location or Region
AKS Environment Name

Create Variables in a file and Reference them¶

Create a variables file 02-variables.tf

# https://www.terraform.io/docs/configuration/variables.html
# Input Variables
# Output Values
# Local Values

# Define Input Variables
# 1. Azure Location (CentralUS)
# 2. Azure Resource Group Name 
# 3. Azure AKS Environment Name (Dev, QA, Prod)
# 4. Azure AKS Cluster Name

# Azure Location
variable "location" {
  type = string
  description = "Azure Region where all these resources will be provisioned"
  default = "Central US"
}

# Azure Resource Group Name
variable "resource_group_name" {
  type = string
  description = "This variable defines the Resource Group"
  default = "terraform-aks"
}

# Azure AKS Environment Name
variable "environment" {
  type = string  
  description = "This variable defines the Environment"  
  default = "prod"
}

Update a file named 03-resource-group.tf with Variable references

# Terraform Resource to Create Azure Resource Group with Input Variables defined in variables.tf
resource "azurerm_resource_group" "aks_rg" {
  location = var.location
  name     = var.resource_group_name
}

Step-08: Terraform Input Variables - Multiple Options¶

Option-1: With -var¶

-var flag enables a single input variable value to be passed in at the command-line per each -var.

# Execute Terraform plan with -var and observe
terraform plan -var "location=eastus"
Observation: Value to should be picked from runtime -var what ever provided which is eastus.

Option-2: With -var-file¶

-var-file flag enables multiple input variable values to be passed in by referencing a file that contains the values.

Create file terraform.tfvars

terraform.tfvars with content in it as 
location = "westus"

# Run plan and observe 
terraform plan 
Observation: No need to give -var-file when name terraform.tfvars and values pickup directly from terraform.tfvars

Rename file name terraform.tfvars to dev.tfvars

# Run plan and observe 
terraform plan 
Observation: dev.tfvars will not be picked and value comes from variables.tf default attribute

# Run plan with -var-file 'dev.tfvars'
terraform plan -var-file 'dev.tfvars'
Observation: value to should be picked from dev.tfvars now

Option-3: With filename.auto.tfvars¶

We already seen the auto loading of .tfvars when the file name is terraform.tfvars
Now we can also do that when we have the file names with filname.auto.tfvars

Lets try out

# Rename file 
mv dev.tfvars dev.auto.tfvars

# Execute Terraform plan (No runtime arguments like -var-file)
terraform plan
Observation: You can see that variable present in dev.auto.tfvars autoloaded now.

Clean-Up: Move dev.auto.tfvars to backup folder for reference and move back to original 02-variables.tf and move to next step.

Option-4: With Environment Variables¶

When running Terraform commands, we can also use Environment Variables to define the values for Input Variables
Important Note: Be sure to keep in mind that if the Operating System is case-sensitive, then Terraform will match variable names exactly as given during configuration.
```
# Template
TF_VAR_<VARIABLE-NAME>  - case-sensitive
# Set Environment Variable using Bash
export TF_VAR_location="westus"
```

Step-09: Final Look of Resource Group¶

Combine Two variables to make it one for resource group

Two have 1 resource group per environment (dev, qa), we are going to use this approach

resource "azurerm_resource_group" "aks_rg" {
  location = var.location
  name     = "${var.resource_group_name}-${var.environment}"
}

Step-10: Define Output Values¶

Understand about Terraform Output Values
Output values are like the return values of a Terraform module
Output values are a way to expose some of that information to the user of your module.
A child module can use outputs to expose a subset of its resource attributes to a parent module

A root module can use outputs to print certain values in the CLI output after running terraform apply

# Create Outputs
# 1. Resource Group Location
# 2. Resource Group Id
# 3. Resource Group Name

output "location" {
  value = azurerm_resource_group.aks_rg.location
}

output "resource_group_id" {
  value = azurerm_resource_group.aks_rg.id
}

output "resource_group_name" {
  value = azurerm_resource_group.aks_rg.name
}

Step-11: Create or Deploy Terraform Resources & Verify¶

# Initialize Terraform 
terraform init

# Validate Terraform Templates
terraform validate

# Execute Terraform Plan
terraform plan
terraform plan -out v1out.plan

# Create / Deploy Terraform Resources
terrafrom apply 
terraform apply v1out.plan 

# Verify current infrastructure state
terraform show

# Format Terraform files
terraform fmt

Step-12: Verify the same in Azure Portal Mgmt Console¶

Verify if Resource Group got created in Azure Mgmt Console
Understand about terraform state file named terraform.tfstate
Migrate this state file to Azure Storage Account

Step-13: Migrate Terraform State Storage to Azure Storage Account¶

Create Azure Storage Account in new Resource Group¶

Why should be we create terraform state storage in different resource group?
State storage is key for all terraform resources and it should be deleted at any point of time even accidentally.
Create New Resource Group: terraform-storage-rg
Create Storage Account: terraformstatexlrwdrzs (Note: Name should be unique across Azure)
Create Container Name: tfstatefiles
Upload the file terraform.tfstate to storage account container

Update main.tf with Terraform State Storage¶

# Configure Terraform State Storage
terraform {
  backend "azurerm" {
    resource_group_name   = "terraform-storage-rg"
    storage_account_name  = "terraformstatexlrwdrzs"
    container_name        = "tfstatefiles"
    key                   = "terraform.tfstate"
  }
}

Migrate terraform backend by re-initializing¶

First backup local terraform.tfstate

# Backup existing terraform.tfstate present locally
mkdir BACKUP-LOCAL-TFSTATE
mv terraform.tfstate BACKUP-LOCAL-TFSTATE

# Try terraform validate
terraform validate

# Try terraform plan (Should fail telling us to re-initialize backed)
terraform plan

# Re-Initialize Terraform Backend
terraform init 

# Verify if any local state file
ls -lrta

This completes successful migration of terraform.tfstate from local to Azure Storage Container
No local dependency now. Straight away initialize your terraform files from any folder and start working

Understand Terraform Language Basics¶

Link to Terraform Configuration Files ¶

Step-01: Introduction¶

Azure Kubernetes Service with Azure DevOps and Terraform¶

Step-02: Terraform Configuration Language Syntax¶

Step-03: Define Terraform Providers¶

Step-04: Define Azure Resource Manager Features Block¶

Step-05: Create Random Pet Resource¶

Step-06: Create a Resource Group Resource¶

Step-07: Understand and Create Terraform Input Variables¶

Three types of Terraform Variables¶

Input Variables¶

Using 02-variables.tf¶

Create Variables in a file and Reference them¶

Step-08: Terraform Input Variables - Multiple Options¶

Option-1: With -var¶

Option-2: With -var-file¶

Option-3: With filename.auto.tfvars¶

Option-4: With Environment Variables¶

Step-09: Final Look of Resource Group¶

Step-10: Define Output Values¶

Step-11: Create or Deploy Terraform Resources & Verify¶

Step-12: Verify the same in Azure Portal Mgmt Console¶

Step-13: Migrate Terraform State Storage to Azure Storage Account¶

Create Azure Storage Account in new Resource Group¶

Update main.tf with Terraform State Storage¶

Migrate terraform backend by re-initializing¶

References¶

Best Selling Azure Kubernetes Service Course on Udemy ¶

Best Selling AWS EKS Kubernetes Course on Udemy ¶

HashiCorp Certified Terraform Associate - 50 Practical Demos ¶

Understand Terraform Language Basics¶

Link to Terraform Configuration Files¶

Step-01: Introduction¶

Azure Kubernetes Service with Azure DevOps and Terraform¶

Step-02: Terraform Configuration Language Syntax¶

Step-03: Define Terraform Providers¶

Step-04: Define Azure Resource Manager Features Block¶

Step-05: Create Random Pet Resource¶

Step-06: Create a Resource Group Resource¶

Step-07: Understand and Create Terraform Input Variables¶

Three types of Terraform Variables¶

Input Variables¶

Using 02-variables.tf¶

Create Variables in a file and Reference them¶

Step-08: Terraform Input Variables - Multiple Options¶

Option-1: With -var¶

Option-2: With -var-file¶

Option-3: With filename.auto.tfvars¶

Option-4: With Environment Variables¶

Step-09: Final Look of Resource Group¶

Step-10: Define Output Values¶

Step-11: Create or Deploy Terraform Resources & Verify¶

Step-12: Verify the same in Azure Portal Mgmt Console¶

Step-13: Migrate Terraform State Storage to Azure Storage Account¶

Create Azure Storage Account in new Resource Group¶

Update main.tf with Terraform State Storage¶

Migrate terraform backend by re-initializing¶

References¶

Best Selling Azure Kubernetes Service Course on Udemy¶

Best Selling AWS EKS Kubernetes Course on Udemy¶

HashiCorp Certified Terraform Associate - 50 Practical Demos¶

Link to Terraform Configuration Files ¶

Best Selling Azure Kubernetes Service Course on Udemy ¶

Best Selling AWS EKS Kubernetes Course on Udemy ¶

HashiCorp Certified Terraform Associate - 50 Practical Demos ¶