40 lines
2.3 KiB
Markdown
40 lines
2.3 KiB
Markdown
---
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layout: "intro"
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page_title: "Terraform vs. CloudFormation, Heat, etc."
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sidebar_current: "vs-other-cloudformation"
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description: |-
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How Terraform compares to other infrastructure as code tools like CloudFormation and Heat. One advantage is that Terraform can simultaneously manage multiple cloud 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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