Ansible vs Terraform: Which One for What Job?
- vinodcloudrocker
- May 7
- 2 min read
Introduction
In the world of DevOps and infrastructure automation, Ansible and Terraform are two of the most popular tools — and for good reason. But they serve different purposes, and choosing the wrong one can lead to wasted effort, messy deployments, or poor scalability.
This post breaks down the core differences, use cases, and gives practical advice on when to use Ansible, Terraform, or both together.
What Are They?
Terraform: Infrastructure as Code (IaC)
Purpose: Provision infrastructure (cloud, networking, compute).
Language: HashiCorp Configuration Language (HCL).
Stateful: Tracks infrastructure changes using a state file.
Idempotent: Yes.
Key Use: Build and tear down cloud resources declaratively.
Ansible: Configuration Management & Automation
Purpose: Configure systems and deploy apps.
Language: YAML (Playbooks).
Agentless: Uses SSH or WinRM (no agents needed on servers).
Idempotent: Yes (to an extent).
Key Use: Install packages, edit configs, orchestrate deployments.
Conceptual Difference
Feature | Terraform | Ansible |
Focus | Infrastructure provisioning | Configuration management |
Execution model | Declarative | Procedural (mostly) |
State tracking | Yes (state files) | No (stateless by default) |
Use case scope | Cloud-native infra | OS-level changes, app deployments |
Example Task | Create VPC, EC2, S3 | Install NGINX, deploy code to server |
Example Use Cases
Use Terraform When:
You want to spin up cloud infrastructure like EC2, RDS, S3, VPCs.
You need multi-cloud provisioning (AWS, Azure, GCP).
You want immutable infrastructure using declarative code.
You're managing long-lived environments (prod/staging/dev).
Use Ansible When:
You need to configure existing servers (install packages, update files).
You're automating application deployment pipelines.
You’re working in environments where SSH access is standard.
You need quick, agentless automation across multiple systems.
Example Workflow:
Use Terraform to create AWS EC2 instances.
Output instance IPs to a file.
Run an Ansible playbook to install NGINX, copy files, and configure firewalls.
This combo provides infrastructure + configuration automation in a clean, scalable pipeline.
Pitfalls to Avoid
Don’t use Ansible to provision cloud infra — it’s possible, but not ideal.
Don’t try to manage OS-level config with Terraform — use Ansible instead.
Be cautious of Terraform state file corruption — use remote backends (S3 + DynamoDB).
Avoid mixing responsibilities — keep infra and config roles separate.
Final Verdict: Which One for What Job?
Task | Best Tool |
Create VPC, EC2, RDS in AWS | Terraform |
Install Docker and deploy app on EC2 | Ansible |
Multi-cloud orchestration (AWS + Azure) | Terraform |
Security patching of Linux servers | Ansible |
Full pipeline: infra + config | Both |
Conclusion
Terraform and Ansible aren’t competitors — they’re complementary. Understanding their strengths allows you to choose the right tool for the job, or better yet, use them together to build fully automated, scalable, and reliable DevOps workflows.
Build with Terraform. Configure with Ansible. Automate everything.
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