Terraform is a tool for building, changing, and versioning infrastructure safely and efficiently. Terraform can manage existing and popular service providers as well as custom in-house solutions. It is a popular tool in DevOps.
- Infrastructure as Code
- Used for the automation of your infrastructure
- It keeps your infrastructure in a certain state (compliant)
- E.g., 2 web instances and 2 volumes and 1 load balancer
- It makes your infrastructure auditable
- That is, you can keep your infrastructure change history in a version control system (e.g., git)
A high-level difference and/or reason to use Terraform over Ansible, Chef, Puppet, Saltstack, etc., is that these others have a focus on automating the installation and configuration of software (i.e., keeping the machines in compliance and in a certain state). Terraform, however, can automate provisioning of the infrastructure itself (e.g., in AWS or Google). One can, of course, do the same with, say, Ansible. However, Terraform really shines in infrastructure management and automation.