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utej8553/Terraform_Init

Terraform learning repository containing infrastructure-as-code examples, experiments, and cloud provisioning practice files.

awshcliaciac-terraformterraform

Terraform_Init

1. Setup & Initialization

Install Terraform

# Linux & macOS
curl -fsSL https://apt.releases.hashicorp.com/gpg | sudo apt-key add -
sudo apt-add-repository "deb [arch=amd64] https://apt.releases.hashicorp.com $(lsb_release -cs) main"
sudo apt-get update && sudo apt-get install terraform

# Verify Installation
terraform -v

Initialize Terraform

terraform init
  • Downloads provider plugins
  • Sets up the working directory

2. Terraform Core Commands

Format & Validate Code

terraform fmt       # Formats Terraform code
terraform validate  # Validates Terraform syntax

Plan & Apply Infrastructure

terraform plan      # Shows execution plan without applying
terraform apply     # Creates/updates infrastructure
terraform apply -auto-approve  # Applies without manual confirmation

Destroy Infrastructure

terraform destroy  # Destroys all managed resources
terraform destroy -auto-approve  # Without confirmation

3. Managing Terraform State

Check Current State

terraform state list  # Lists all managed resources
terraform show        # Shows detailed resource info

Manually Modify State

terraform state mv <source> <destination>  # Move resource in state file
terraform state rm <resource>  # Removes resource from state (not from infra)

Remote Backend (S3 & DynamoDB)

terraform {
  backend "s3" {
    bucket         = "my-terraform-state"
    key            = "global/s3/terraform.tfstate"
    region         = "us-east-1"
    dynamodb_table = "terraform-lock"
    encrypt        = true
  }
}
terraform init  # Reinitialize with remote backend

4. Variables & Outputs

Define & Use Variables

variable "instance_type" {
  default = "t2.micro"
}
resource "aws_instance" "web" {
  instance_type = var.instance_type
}

Pass Variables in CLI

terraform apply -var="instance_type=t3.small"

Output Values

output "instance_ip" {
  value = aws_instance.web.public_ip
}
terraform output instance_ip

5. Loops & Conditionals

for_each Example

resource "aws_s3_bucket" "example" {
  for_each = toset(["bucket1", "bucket2", "bucket3"])
  bucket   = each.key
}

Conditional Expressions

variable "env" {}
resource "aws_instance" "example" {
  instance_type = var.env == "prod" ? "t3.large" : "t2.micro"
}

6. Terraform Modules

Create & Use a Module

mkdir -p modules/vpc
# modules/vpc/main.tf
resource "aws_vpc" "main" {
  cidr_block = "10.0.0.0/16"
}
# Root module
module "vpc" {
  source = "./modules/vpc"
}
terraform init
terraform apply

7. Workspaces (Environment Management)

Create & Switch Workspaces

terraform workspace new dev
terraform workspace new prod
terraform workspace select prod
terraform workspace list

8. Terraform Debugging & Logs

export TF_LOG=DEBUG  # Enable debug logs
terraform apply 2>&1 | tee debug.log  # Save logs

Contributors

UT
Created February 19, 2026
Updated February 26, 2026