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What is the difference between Terraform and CloudFormation, and when choose each?

Infrastructure as Code (Terraform, Ansible) · Intermediate level

Answer

Terraform is multi-cloud and provider-based, with HCL modules and a broad ecosystem. CloudFormation is AWS-native, deeply integrated with AWS services, and supported directly by AWS. I choose Terraform for cross-cloud or standard platform workflows; CloudFormation when AWS-native support, StackSets, or service coverage is the decisive factor.

Technical explanation

Terraform's provider ecosystem is broader; CloudFormation's AWS integration can be deeper on day-zero AWS features.

CloudFormation state is managed by AWS stacks; Terraform state is managed by the selected backend.

Operational familiarity and governance requirements often decide the choice.

Keep Terraform's ownership boundary clear: one state should own a resource or field, and other tools should consume published outputs instead of modifying it.

Use fmt, validate, linting, policy checks, plan review, and state locking before production applies.

Design for small blast radius by splitting state around lifecycle, permissions, and recovery boundaries.

Hands-on example

1. Build a safe IaC delivery workflow for: What is the difference between Terraform and CloudFormation, and when choose each?

2. Pull request job:

terraform fmt -check

terraform init -backend=false

terraform validate

tflint --recursive

checkov -d .

terraform init

terraform plan -out=tfplan

terraform show -json tfplan > tfplan.json

3. Policy job evaluates plan JSON for public exposure, missing encryption, IAM wildcards, and destructive changes.

4. Apply job runs only after approval, uses remote state locking, short-lived cloud credentials, and applies the saved plan artifact.

5. For failures, rerun plan, inspect state and cloud objects, and fix root cause before any state surgery.

More Infrastructure as Code (Terraform, Ansible) interview questions

• What is Infrastructure as Code, and what problems does it solve over click-ops?
• What is the difference between declarative and imperative IaC, and where do Terraform and Ansible fall?
• What is the difference between configuration management and provisioning?
• What is Terraform, and what is the core plan/apply workflow?
• What does terraform init do?
• What is the Terraform state file, and why is it critical?
• Why should state be stored remotely, and what backend would you use on AWS?
• What is state locking, and why does it matter for teams?

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