When automating infrastructure and configuration, two tools often come up in conversation: Ansible and Terraform. Both are widely used in the DevOps ecosystem, but they serve different purposes and shine in different use cases.
This post breaks down the key differences between the two to help you decide when to use one, the other, or both.
What is Terraform?
Terraform, developed by HashiCorp, is an Infrastructure as Code (IaC) tool used to provision and manage infrastructure across multiple cloud providers and services. It describes infrastructure in a declarative manner using HCL (HashiCorp Configuration Language) and focuses on creating and updating infrastructure components like networks, servers, databases, and more.
What is Ansible?
Ansible, created by Red Hat, is a Configuration Management tool that automates application deployment, configuration enforcement, and task execution on servers. It uses YAML-based playbooks and operates agentlessly over SSH (or WinRM for Windows).
⚔️ Key Differences
| Feature | Terraform | Ansible |
|---|---|---|
| Primary Use Case | Infrastructure provisioning | Configuration management |
| Language | HCL (declarative) | YAML (mostly imperative) |
| Agent Required | No | No |
| State Management | Yes (keeps a state file) | No (stateless by default) |
| Idempotency | Strong | Manual control |
| Cloud Provider Support | Broad (multi-cloud) | Good, but secondary to server config |
| Complexity Handling | Modules and dependencies | Roles, inventories, dynamic vars |
| Execution Mode | Plan & apply changes | Execute tasks immediately |
Can They Work Together?
Yes, in fact, many teams use both:
- Use Terraform to provision cloud resources (e.g., VMs, networks, security groups).
- Use Ansible to configure those resources post-provisioning (e.g., install software, configure services).
This combo provides both the infrastructure scaffolding and the operational configuration in a repeatable and automated way.
When to Use What?
| Scenario | Recommended Tool |
|---|---|
| Creating cloud infrastructure | Terraform |
| Enforcing system configuration | Ansible |
| Multi-cloud orchestration | Terraform |
| Installing and configuring applications | Ansible |
| Managing infrastructure dependencies | Terraform |
| Ad-hoc server updates or tasks | Ansible |
📘 Resources to Explore
- Terraform Docs
- Ansible Docs
- terraform-sandbox-template: For testing and learning Terraform
- ansible-sandbox-template: For experimenting with Ansible playbooks and setups
🧠 Final Thoughts
Terraform and Ansible are not competitors, they are complementary. Terraform is your go-to for setting up infrastructure. Ansible shines when it’s time to configure and maintain that infrastructure.
Together, they provide a robust DevOps toolchain for managing cloud environments effectively and predictably.
Choose the right tool for the right job, or better yet, use both. 🚀