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