Terraform vs Ansible
Compare infrastructure provisioning with configuration management and automation.
Infrastructure
Terraform
Terraform is an infrastructure-as-code tool used to provision cloud resources and platform components declaratively. It is commonly used for networks, compute, databases, IAM, and other infrastructure building blocks.
Infrastructure
Ansible
Ansible is an automation and configuration management tool used to install software, manage files, configure systems, and orchestrate operational workflows on existing infrastructure.
Key Differences
Terraform is mainly used to provision infrastructure resources, while Ansible is mainly used to configure and automate systems after infrastructure exists.
Terraform is declarative and state-driven, while Ansible is task-driven and procedural in style, even though it aims for idempotency.
Terraform usually answers 'what infrastructure should exist', while Ansible often answers 'what should be done on these machines'.
Terraform is stronger for cloud resource lifecycle management, while Ansible is stronger for package installation, configuration changes, and host automation.
Terraform depends heavily on state tracking, while Ansible usually operates more directly against current host state.
These tools are often complementary in real-world DevOps workflows rather than direct replacements for each other.
When to Use
When to use Terraform
Use Terraform when you need repeatable provisioning of cloud infrastructure such as VPCs, subnets, instances, security groups, managed databases, or IAM resources.
When to use Ansible
Use Ansible when you need to configure servers, install dependencies, deploy applications, manage files, or automate post-provisioning operational workflows.
Tradeoffs
Terraform is excellent for provisioning, but weaker for detailed host configuration workflows.
Ansible is excellent for configuration and automation, but less suited to full cloud infrastructure lifecycle management.
Used together, they often form a stronger workflow than either tool used alone for everything.
Common Mistakes
Trying to use Ansible as the primary solution for all cloud provisioning at scale.
Trying to use Terraform for every configuration change inside running servers.
Treating them as competitors instead of different layers of automation.
Interview Tip
A clear answer is: Terraform provisions infrastructure, Ansible configures what runs on top of it.