30 Terraform Interview Questions to Ace Your DevOps Interview in 2025

This ultimate interview prep guide covers Terraform basics and advanced scenarios, including HCL syntax, Terraform modules, state management, and real-world examples for DevOps engineers in 2025.

Optimized for “Terraform DevOps interview”, this article includes:

• HCL code snippets
• Tips on securing state files
• Links to live job opportunities at www.clouddevopsjobs.com
• A YouTube Short suggestion to boost engagement

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Introduction: Why Terraform Is Critical in DevOps Roles in 2025

With multi-cloud environments becoming standard, Terraform remains the most adopted Infrastructure as Code (IaC) tool. Whether you’re applying for a DevOps, SRE, or platform engineering role — Terraform expertise is expected.

This guide contains 30 Terraform interview questions to help you prep confidently in 2025.

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Section 1: Terraform Basics

1. What is Terraform?
Terraform is an open-source IaC tool by HashiCorp. It lets you define and provision infrastructure using HCL (HashiCorp Configuration Language) across multiple providers.

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2. What are the key components of a Terraform configuration?

• Providers
• Resources
• Variables
• Outputs
• Modules
• State

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3. What is a Terraform provider?
Providers are plugins that let Terraform interact with external APIs (AWS, Azure, GCP, Kubernetes, etc.).

hclCopyEditprovider "aws" {
  region = "us-west-2"
}

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4. How do you define a simple AWS S3 bucket in Terraform?

hCopyEditresource "aws_s3_bucket" "my_bucket" {
  bucket = "my-unique-bucket-2025"
  acl    = "private"
}

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5. What is terraform init used for?
Initializes the working directory by downloading provider plugins and preparing backends.

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Section 2: Intermediate Terraform Topics

6. What is a Terraform module?
Reusable blocks of Terraform code for DRY (Don’t Repeat Yourself) practices.

hclCopyEditmodule "vpc" {
  source     = "./modules/vpc"
  cidr_block = "10.0.0.0/16"
}

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7. Difference between terraform plan and terraform apply?

• terraform plan: Shows what changes Terraform will make
• terraform apply: Executes those changes

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8. How do you pass variables into Terraform?

hclCopyEditvariable "region" {
  default = "us-east-1"
}

provider "aws" {
  region = var.region
}

Override using terraform.tfvars or CLI args.

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9. What is a data source in Terraform?

hclCopyEditdata "aws_ami" "ubuntu" {
  most_recent = true
  owners      = ["099720109477"]
  filter {
    name   = "name"
    values = ["ubuntu/images/hvm-ssd/ubuntu-focal*"]
  }
}

Data sources fetch read-only data from providers.

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10. What is Terraform output and why is it used?

hclCopyEditoutput "bucket_name" {
  value = aws_s3_bucket.my_bucket.id
}

Outputs expose infrastructure values to users or other configurations.

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Section 3: Terraform State and Backend Management

11. What is the Terraform state file?
terraform.tfstate tracks current infrastructure state for change detection.

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12. How do you manage Terraform state securely?

• Use remote backends (e.g., S3 + DynamoDB lock)
• Enable encryption & versioning
• Use role-based access control (RBAC)

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13. What is a backend in Terraform?
Controls how state is loaded/stored. Examples:

• local (default)
• s3, gcs, azurerm, remote, etc.

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14. Example: Configuring S3 remote backend with locking

hclCopyEditterraform {
  backend "s3" {
    bucket         = "my-tf-state"
    key            = "prod/terraform.tfstate"
    region         = "us-west-2"
    dynamodb_table = "tf-locks"
    encrypt        = true
  }
}

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15. What happens if two users run Terraform at the same time?
Without backend locking (e.g., DynamoDB), state corruption may occur.

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Section 4: Terraform CLI & Workflows

16. Difference between terraform destroy and terraform taint?

• destroy: Deletes all resources
• taint: Marks a specific resource for recreation

bashCopyEditterraform taint aws_instance.my_vm

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17. How do you import existing infrastructure into Terraform?

bashCopyEditterraform import aws_instance.my_vm i-0123456789abcdef0

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18. What is terraform validate used for?
Checks syntax and configuration structure.

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19. What does terraform fmt do?
Formats .tf files to canonical HCL style.

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20. How do you use workspaces in Terraform?

bashCopyEditterraform workspace new staging
terraform workspace select prod

Use workspaces to manage multiple environments.

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Section 5: Advanced Terraform + Real-World Scenarios

21. How do you handle secrets in Terraform?

• Never hardcode secrets
• Use environment variables
• Integrate with Vault, AWS Secrets Manager, or Azure Key Vault

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22. Terraform Cloud vs Terraform Enterprise
Provides:

• Remote state
• Team collaboration
• Policy enforcement (Sentinel)
• Secure execution environments

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23. What are dynamic blocks in Terraform?

hclCopyEditdynamic "tag" {
  for_each = var.tags
  content {
    key   = tag.key
    value = tag.value
  }
}

Used for conditional logic in resources/attributes.

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24. What is Sentinel?
A policy-as-code framework for compliance in Terraform Cloud/Enterprise.

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25. Terraform vs CloudFormation

Feature	Terraform	CloudFormation
Multi-Cloud	✅ Yes	❌ AWS-only
Language	HCL	JSON/YAML
Community	Open-source	AWS-focused
Testing	3rd-party tools	Limited support

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Section 6: Scenario-Based Terraform Interview Questions

26. How would you build a reusable VPC module?

• Create main.tf, variables.tf, outputs.tf
• Parameterize region, CIDRs, subnets
• Use module block to reuse in environments

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27. You manually deleted a resource. What happens?
Terraform will detect it on plan and may recreate it unless removed from code.

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28. How do you handle multiple cloud providers?

hclCopyEditprovider "aws" {
  region = "us-east-1"
}

provider "google" {
  project = "my-gcp-project"
}

Use alias for multiple accounts.

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29. How do you test Terraform modules?

• terraform validate
• terraform plan with test vars
• Use Terratest, Kitchen-Terraform, GitHub Actions for CI

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30. Best Practices for Terraform

• Use modules and version control
• Secure state files
• Lock versions of providers/modules
• Use terraform-docs
• Apply RBAC with least privilege

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YouTube Short Suggestion

Embed:
“Intro to Terraform in 60 Seconds”
A short video explaining providers, resources, and HCL basics to boost engagement and SEO.

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Bonus Download: AWS S3 + Remote Backend Template

Grab a ready-made .tf config with:

• Encrypted S3 bucket
• Remote backend with locking
• Tags, versioning, and outputs

Download: clouddevopsjobs.com/resources

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Find Terraform DevOps Jobs

Explore active roles like:

• Terraform DevOps Engineer
• Infrastructure as Code Specialist
• AWS Platform Engineer
• Multi-Cloud Automation Architect

Apply now: www.clouddevopsjobs.com

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Final Thoughts

If you’re prepping for a Terraform interview, this guide helps you showcase:

• Real-world IaC experience
• Mastery of HCL and modules
• Secure and scalable infrastructure management

Share this guide on X/Twitter with #Terraform #DevOpsInterview #IaC2025
Recommend to your team as a prep checklist or onboarding resource.