Terraform Settings
The special terraform
configuration block type is used to configure some
behaviors of Terraform itself, such as requiring a minimum Terraform version to
apply your configuration.
Terraform Block Syntax
Terraform settings are gathered together into terraform
blocks:
Each terraform
block can contain a number of settings related to Terraform's
behavior. Within a terraform
block, only constant values can be used;
arguments may not refer to named objects such as resources, input variables,
etc, and may not use any of the Terraform language built-in functions.
The various options supported within a terraform
block are described in the
following sections.
Configuring Terraform Cloud
The nested cloud
block configures Terraform Cloud for enabling its
CLI-driven run workflow.
Refer to Terraform Cloud Configuration for a summary of the
cloud
block's syntax.Refer to Using Terraform Cloud in the Terraform CLI documentation for complete details about how to initialize and configure the Terraform Cloud CLI integration.
Configuring a Terraform Backend
The nested backend
block configures which state backend Terraform should use.
The syntax and behavior of the backend
block is described in Backend
Configuration.
Specifying a Required Terraform Version
Hands-on: Try the Manage Terraform Versions or Manage Terraform Versions in Terraform Cloud tutorials.
The required_version
setting accepts a version constraint
string, which specifies which versions of Terraform
can be used with your configuration.
If the running version of Terraform doesn't match the constraints specified, Terraform will produce an error and exit without taking any further actions.
When you use child modules, each module can specify its own version requirements. The requirements of all modules in the tree must be satisfied.
Use Terraform version constraints in a collaborative environment to ensure that everyone is using a specific Terraform version, or using at least a minimum Terraform version that has behavior expected by the configuration.
The required_version
setting applies only to the version of Terraform CLI.
Terraform's resource types are implemented by provider plugins,
whose release cycles are independent of Terraform CLI and of each other.
Use the required_providers
block to manage
the expected versions for each provider you use.
Specifying Provider Requirements
The required_providers
block specifies all of the providers required by the
current module, mapping each local provider name to a source address and a
version constraint.
For more information, see Provider Requirements.
Experimental Language Features
The Terraform team will sometimes introduce new language features initially via an opt-in experiment, so that the community can try the new feature and give feedback on it prior to it becoming a backward-compatibility constraint.
In releases where experimental features are available, you can enable them on
a per-module basis by setting the experiments
argument inside a terraform
block:
The above would opt in to an experiment named example
, assuming such an
experiment were available in the current Terraform version.
Experiments are subject to arbitrary changes in later releases and, depending on the outcome of the experiment, may change drastically before final release or may not be released in stable form at all. Such breaking changes may appear even in minor and patch releases. We do not recommend using experimental features in Terraform modules intended for production use.
In order to make that explicit and to avoid module callers inadvertently
depending on an experimental feature, any module with experiments enabled will
generate a warning on every terraform plan
or terraform apply
. If you
want to try experimental features in a shared module, we recommend enabling the
experiment only in alpha or beta releases of the module.
The introduction and completion of experiments is reported in Terraform's changelog, so you can watch the release notes there to discover which experiment keywords, if any, are available in a particular Terraform release.
Passing Metadata to Providers
The terraform
block can have a nested provider_meta
block for each
provider a module is using, if the provider defines a schema for it. This
allows the provider to receive module-specific information, and is primarily
intended for modules distributed by the same vendor as the associated provider.
For more information, see Provider Metadata.