10 Terraform Interview Questions You Must Know in 2025
If you’re preparing for a Cloud Engineer or DevOps Engineer interview in 2025, you must know Terraform—it’s one of the most in-demand tools for managing cloud infrastructure.
Today, we’re covering 10 must-know Terraform interview questions to help you land your next DevOps job! Stay tuned for expert tips and real-world examples. Let’s jump in!
Question 1: What is Terraform and why should you care?
So, Terraform is a free tool made by HashiCorp. It lets you manage your cloud infrastructure — like servers, databases, networks — using code instead of clicking around in a user interface like the AWS console.
Basically, you write some config files, and Terraform builds all your resources for you.
Why it’s useful:
- First, you don’t have to do things manually anymore.
- Second, your environments — dev, test, prod — stay consistent.
- And finally, it works with multiple cloud providers like AWS, Azure, and Google Cloud Platform.
Example: Need 5 EC2 instances in AWS? Instead of setting them up one by one, you write a script in Terraform — and it will set everything up for you in one go.
🚀 Pro Tip: If someone asks how Terraform is different from tools like Ansible or CloudFormation, here’s a simple way to explain it: Terraform describes the end goal — what you want things to look like — while Ansible is more about the step-by-step process to get there.
Question 2: What are the main parts of Terraform?
Let’s break it down. There are three main pieces you should know:
- First, Providers — they connect Terraform to cloud platforms like AWS, Azure, GCP, and so on.
- Then we have Modules — these are chunks of reusable code that help you avoid repeating yourself.
- And lastly, there’s State — this is a file that keeps track of what Terraform has already created.
Example: If you’re creating a server on AWS, the provider tells Terraform, “Hey, we’re using AWS,” and then you can use a module to automatically handle networking, storage, and so on.
Question 3: What is Terraform State and why is it important?
Terraform State is just a file that remembers everything Terraform has built.
Here’s why it matters:
- First, it helps by keeping track of what already exists in your infrastructure.
- Second, it figures out the relationships — or dependencies — between different resources.
- And third, it allows your whole team to collaborate effectively — particularly when the state file is stored remotely, which is key for team-based setups.
But here’s something a lot of people get wrong: saving state on your laptop. If something happens to your computer, you could lose all your Terraform tracking.
🚀 Pro Tip: Store state in S3 and use DynamoDB for locking, or just go with Terraform Cloud to make life easier. And if someone mentions “state locking,” it’s basically just a way to stop multiple people from making changes at the same time.
Question 4: What’s the difference between Terraform Plan and Apply?
It’s simple:
-
terraform planshows you what changes Terraform is going to make. -
terraform applyactually makes those changes.
Example: Let’s say you change an EC2 instance type from t2.micro to t3.micro. terraform plan will say, “Hey, this is the difference,” and terraform apply will go ahead and make it happen.
🚀 Pro Tip: Before you apply any changes, it’s a good idea to run terraform plan and save the output to a file. This way, you can double-check what’s about to happen and avoid surprises.
Question 5: How does Terraform handle dependencies?
Terraform usually understands dependencies on its own, just by looking at how your resources are connected.
But if you really need to, you can use depends_on to say, “Hey, make sure this thing is done first.”
Example: You’re creating an EC2 instance that needs a VPC. Terraform will automatically know to create the VPC first.
🚀 Pro Tip: Try not to rely too much on depends_on. Terraform is smart and can usually handle this without extra help.
Question 6: What is Terraform Drift and how do you find it?
Drift is when something in your cloud setup changes outside of Terraform — like if someone makes a manual change in the AWS Console — and now your code doesn’t line up with what’s actually running.
To spot that kind of difference, you can run terraform plan. It’ll show you if anything has changed that Terraform didn’t expect.
🚀 Pro Tip: If you want to keep everything organized and up to date, you can set up automatic drift checks in Terraform Cloud, or add a simple step to your automation setup to check for changes from time to time.
Question 7: How do you handle sensitive data in Terraform?
Here’s how to deal with secrets safely:
- First, use variables and set
sensitive = true. - Then, store secrets in something secure like AWS Secrets Manager or Vault.
- And finally, make sure your remote state is encrypted.
🚨 And seriously — never put passwords directly in your code or state files.
Question 8: What are Terraform Workspaces?
Workspaces let you use the same Terraform config for different environments — like dev, staging, and prod.
🔹 You can run commands like:
terraform workspace new devterraform workspace select dev
🚀 Pro Tip: Workspaces are fine for small projects, but for bigger systems, using separate state files is usually better.
Question 9: What are Terraform Modules and why use them?
Modules are just reusable bits of code that make your Terraform setup easier to manage.
Here’s why they’re helpful:
- First of all, they help you avoid repeating the same code in every project.
- They also keep your files nice and organized.
- And finally, they help make sure your infrastructure stays consistent everywhere.
📌 Example: You can create a module for a VPC and use it in multiple places instead of writing that code over and over.
🚀 Pro Tip: Before writing your own module, check out the Terraform Registry. Someone else may have already built what you need.
Question 10: How do you use Terraform in an automated deployment process?
You can plug Terraform into your CI/CD setup using tools like:
- GitHub Actions
- GitLab CI
- Terraform Cloud
🛠 Here’s a basic workflow:
- First, run
terraform fmtandterraform validateto check formatting and syntax. - Then, use
terraform planto preview the changes. - And finally, use
terraform applyonly after someone gives the green light (especially in production).
🚀 Pro Tip: Some teams also use Open Policy Agent to apply security rules before changes are applied.
🔥 Alright, that’s it for today! These 10 Terraform questions should give you a solid foundation for your next DevOps interview.
Thanks for reading! Be sure to watch the video version for extra insights and helpful visuals.
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Absolutely not! Every article is written by me, driven by a genuine passion for Docker and backed by decades of experience in IT. I do use AI tools to polish grammar and enhance clarity, but the ideas, strategies, and technical insights are entirely my own. While this might occasionally trigger AI detection tools, rest assured—the knowledge and experience behind the content are 100% real and personal.
