72 lines
3.4 KiB
Markdown
72 lines
3.4 KiB
Markdown
---
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layout: "docs"
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page_title: "Provisioning Infrastructure - Terraform CLI"
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---
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# Provisioning Infrastructure with Terraform
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Terraform's primary function is to create, modify, and destroy infrastructure
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resources to match the desired state described in a
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[Terraform configuration](/docs/configuration/index.html).
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When people refer to "running Terraform," they generally mean performing these
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provisioning actions in order to affect real infrastructure objects. The
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Terraform binary has many other subcommands for a wide variety of administrative
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actions, but these basic provisioning tasks are the core of Terraform.
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Terraform's provisioning workflow relies on three commands: `plan`, `apply`, and
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`destroy`. All of these commands require an
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[initialized](/docs/cli/init/index.html) working directory, and all of them act
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only upon the currently selected [workspace](/docs/cli/workspaces/index.html).
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## Planning
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The `terraform plan` command evaluates a Terraform configuration to determine
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the desired state of all the resources it declares, then compares that desired
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state to the real infrastructure objects being managed with the current working
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directory and workspace. It uses state data to determine which real objects
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correspond to which declared resources, and checks the current state of each
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resource using the relevant infrastructure provider's API.
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Once it has determined the difference between the current state and the desired
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state, `terraform plan` presents a description of the changes necessary to
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achieve the desired state. It _does not_ perform any actual changes to real
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world infrastructure objects; it only presents a plan for making changes.
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Plans are usually run to validate configuration changes and confirm that the
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resulting actions are as expected. However, `terraform plan` can also save its
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plan as a runnable artifact, which `terraform apply` can use to carry out those
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exact changes.
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For details, see [the `terraform plan` command](/docs/commands/plan.html).
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## Applying
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The `terraform apply` command performs a plan just like `terraform plan` does,
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but then actually carries out the planned changes to each resource using the
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relevant infrastructure provider's API. It asks for confirmation from the user
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before making any changes, unless it was explicitly told to skip approval.
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By default, `terraform apply` performs a fresh plan right before applying
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changes, and displays the plan to the user when asking for confirmation.
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However, it can also accept a plan file produced by `terraform plan` in lieu of
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running a new plan. You can use this to reliably perform an exact set of
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pre-approved changes, even if the configuration or the state of the real
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infrastructure has changed in the minutes since the original plan was created.
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For details, see [the `terraform apply` command](/docs/commands/apply.html).
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## Destroying
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The `terraform destroy` command destroys all of the resources being managed by
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the current working directory and workspace, using state data to determine which
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real world objects correspond to managed resources. Like `terraform apply`, it
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asks for confirmation before proceeding.
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A destroy behaves exactly like deleting every resource from the configuration
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and then running an apply, except that it doesn't require editing the
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configuration. This is more convenient if you intend to provision similar
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resources at a later date.
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For details, see [the `terraform destroy` command](/docs/commands/destroy.html).
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