| --- |
| page_title: 'Terraform vs. CloudFormation, Heat, etc.' |
| description: >- |
| How Terraform compares to other infrastructure as code tools like |
| CloudFormation and Heat. Terraform can simultaneously manage multiple cloud |
| providers (AWS, OpenStack, etc.) and services (Cloudflare, DNSimple, etc.). |
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| |
| # Terraform vs. CloudFormation, Heat, etc. |
| |
| Tools like CloudFormation, Heat, etc. allow the details of an infrastructure |
| to be codified into a configuration file. The configuration files allow |
| the infrastructure to be elastically created, modified and destroyed. Terraform |
| is inspired by the problems they solve. |
| |
| Terraform similarly uses configuration files to detail the infrastructure |
| setup, but it goes further by being both cloud-agnostic and enabling |
| multiple providers and services to be combined and composed. For example, |
| Terraform can be used to orchestrate an AWS and OpenStack cluster simultaneously, |
| while enabling 3rd-party providers like Cloudflare and DNSimple to be integrated |
| to provide CDN and DNS services. This enables Terraform to represent and |
| manage the entire infrastructure with its supporting services, instead of |
| only the subset that exists within a single provider. It provides a single |
| unified syntax, instead of requiring operators to use independent and |
| non-interoperable tools for each platform and service. |
| |
| Terraform also separates the planning phase from the execution phase, |
| by using the concept of an execution plan. By running `terraform plan`, |
| the current state is refreshed and the configuration is consulted to |
| generate an action plan. The plan includes all actions to be taken: |
| which resources will be created, destroyed or modified. It can be |
| inspected by operators to ensure it is exactly what is expected. Using |
| `terraform graph`, the plan can be visualized to show dependent ordering. |
| Once the plan is captured, the execution phase can be limited to only |
| the actions in the plan. Other tools combine the planning and execution |
| phases, meaning operators are forced to mentally reason about the effects |
| of a change, which quickly becomes intractable in large infrastructures. |
| Terraform lets operators apply changes with confidence, as they know exactly |
| what will happen beforehand. |
