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Chapter 43: Terraform Interview Questions and Capstone Project

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Chala mitrano, shevtcha Terraform chapter. Aadhi interview che prashna — concepts aani scenarios. Mag capstone: module, remote state, dev aani prod, Jenkins pipeline scan aani approval sobat. Pratyek goshticha proof theva. Ani shevti sagla destroy.

What you will learn in this chapter

  • Explain a Terraform snippet line by line in an interview
  • Answer core and scenario questions in the right order
  • Build the capstone repository
  • Prove every requirement and destroy everything

Concepts in this chapter

  1. 43.1Interview round 1 — core concepts
  2. 43.2Interview round 2 — scenarios
  3. 43.3Capstone part 1 — the brief and the repository layout
  4. 43.4Capstone part 2 — requirements, proof and destroy

The chapter recap is at the end of the last concept page.

Practice Tasks

About this scenario

Suppose we are on the DevOps team at Zerodha, the stock broking company, working from Bengaluru. Nikhil Joshi leads the team, and we look after the order book service. Costs are counted in INR. In the tasks below we do real DevOps jobs on this project using what this lesson teaches. Zerodha is a real company, but this project, the people, servers, IP addresses and numbers are made up for practice.

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Easy Name the practice

Why: IaC is the base of repeatable cloud setups.

What to do: Zerodha describes its servers, networks and databases in text files kept in Git and creates them with a tool. What is this called (three-letter short form)?

How:
  1. Write down the facts or numbers the task gives you.
  2. Work it out step by step.
  3. Type only the final answer (one word or number) in the box.
  4. Click Check answer.

Easy S3 bucket resource

Why: Buckets in code are reviewed and never forgotten.

What to do: Write a resource aws_s3_bucket named logs with bucket = "zerodha-logs" and tags { Team = "devops" }.

How:
  1. Write the block type (resource, variable, output, module...) and its labels in quotes.
  2. Open { and write each argument as name = value.
  3. Put text values in double quotes; numbers and true/false without quotes.
  4. Close every block with } and click Check answer.

Easy Output a value

Why: Outputs hand values to scripts and other modules.

What to do: Write output "web_ip" with value = aws_instance.web.public_ip.

How:
  1. Write the block type (resource, variable, output, module...) and its labels in quotes.
  2. Open { and write each argument as name = value.
  3. Put text values in double quotes; numbers and true/false without quotes.
  4. Close every block with } and click Check answer.

Easy Provider block

Why: The provider tells Terraform which cloud and region to talk to.

What to do: Write a provider "aws" block with region = "ap-south-1".

How:
  1. Write the block type (resource, variable, output, module...) and its labels in quotes.
  2. Open { and write each argument as name = value.
  3. Put text values in double quotes; numbers and true/false without quotes.
  4. Close every block with } and click Check answer.

Medium EC2 instance using a variable

Why: Referencing var.* avoids hard-coding sizes.

What to do: Write resource aws_instance "web" with ami = "ami-0abcdef1234567890", instance_type = var.instance_type and tags Name = "order-book".

How:
  1. Write the block type (resource, variable, output, module...) and its labels in quotes.
  2. Open { and write each argument as name = value.
  3. Put text values in double quotes; numbers and true/false without quotes.
  4. Close every block with } and click Check answer.

Medium Pin the provider version

Why: Pinning stops a new provider release from breaking your plan.

What to do: Write a terraform block with required_providers aws = { source = "hashicorp/aws", version = "~> 5.0" }.

How:
  1. Write the block type (resource, variable, output, module...) and its labels in quotes.
  2. Open { and write each argument as name = value.
  3. Put text values in double quotes; numbers and true/false without quotes.
  4. Close every block with } and click Check answer.

Medium List resources in state

Why: state list shows what Terraform thinks it manages.

What to do: List every resource address in the state.

How:
  1. Read the task and pick the tool it needs (git, docker, kubectl, terraform, ansible...).
  2. Write the tool name, then the sub-command (the action word).
  3. Add the flags the task needs, each followed by its value.
  4. Add names, files or paths at the end, then click Check answer.

Hard Remote state in S3

Why: Shared remote state with locking stops two people breaking each other.

What to do: Write a terraform block with backend "s3": bucket = "zerodha-tfstate", key = "prod/terraform.tfstate", region = "ap-south-1", dynamodb_table = "tf-lock".

How:
  1. Write the block type (resource, variable, output, module...) and its labels in quotes.
  2. Open { and write each argument as name = value.
  3. Put text values in double quotes; numbers and true/false without quotes.
  4. Close every block with } and click Check answer.

Hard Call a module

Why: Modules package a tested pattern, like a VPC, for reuse.

What to do: Write module "vpc" with source = "terraform-aws-modules/vpc/aws", version = "5.8.1", name = "zerodha-vpc" and cidr = "10.0.0.0/16".

How:
  1. Write the block type (resource, variable, output, module...) and its labels in quotes.
  2. Open { and write each argument as name = value.
  3. Put text values in double quotes; numbers and true/false without quotes.
  4. Close every block with } and click Check answer.

Hard Create several copies with count

Why: count builds N identical resources from one block.

What to do: Write resource aws_instance "worker" with count = 5, ami = "ami-0abcdef1234567890", instance_type = "t3.small" and tags Name = "worker-${count.index}".

How:
  1. Write the block type (resource, variable, output, module...) and its labels in quotes.
  2. Open { and write each argument as name = value.
  3. Put text values in double quotes; numbers and true/false without quotes.
  4. Close every block with } and click Check answer.

Hard Security group for HTTPS

Why: Opening only 443 keeps the attack surface small.

What to do: Write resource aws_security_group "web" with name = "web-sg" and one ingress block: from_port = 443, to_port = 443, protocol = "tcp", cidr_blocks = ["0.0.0.0/0"].

How:
  1. Write the block type (resource, variable, output, module...) and its labels in quotes.
  2. Open { and write each argument as name = value.
  3. Put text values in double quotes; numbers and true/false without quotes.
  4. Close every block with } and click Check answer.

Hard Import an existing bucket

Why: Import brings hand-made resources under code control.

What to do: Import the existing S3 bucket zerodha-logs into the address aws_s3_bucket.logs.

How:
  1. Read the task and pick the tool it needs (git, docker, kubectl, terraform, ansible...).
  2. Write the tool name, then the sub-command (the action word).
  3. Add the flags the task needs, each followed by its value.
  4. Add names, files or paths at the end, then click Check answer.

See all DevOps practice tasks in the Task Hub →

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