AWS

Authentication and Configuration

Configuration for the AWS Provider can be derived from several sources, which are applied in the following order:

  1. Parameters in the provider configuration

  2. Environment variables

  3. Shared credentials files

  4. Shared configuration files

  5. Container credentials

  6. Instance profile credentials and region

This order matches the precedence used by the AWS CLI and the AWS SDKs.

The AWS Provider supports assuming an IAM role, either in the provider configuration block parameter assume_role or in a named profile.

The AWS Provider supports assuming an IAM role using web identity federation and OpenID Connect (OIDC). This can be configured either using environment variables or in a named profile.

When using a named profile, the AWS Provider also supports sourcing credentials from an external process.

Provider Configuration

Warning:

Hard-coded credentials are not recommended in any Terraform configuration and risks secret leakage should this file ever be committed to a public version control system.

Credentials can be provided by adding an access_key, secret_key, and optionally token, to the aws provider block.

Usage:

provider "aws" {
  region     = "us-west-2"
  access_key = "my-access-key"
  secret_key = "my-secret-key"
}

Other settings related to authorization can be configured, such as:

Environment Variables

Credentials can be provided by using the AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY, and optionally AWS_SESSION_TOKEN environment variables. The region can be set using the AWS_REGION or AWS_DEFAULT_REGION environment variables.

For example:

provider "aws" {}
$ export AWS_ACCESS_KEY_ID="anaccesskey"
$ export AWS_SECRET_ACCESS_KEY="asecretkey"
$ export AWS_REGION="us-west-2"
$ terraform plan

Other environment variables related to authorization are:

Shared Configuration and Credentials Files

The AWS Provider can source credentials and other settings from the shared configuration and credentials files. By default, these files are located at $HOME/.aws/config and $HOME/.aws/credentials on Linux and macOS, and "%USERPROFILE%\.aws\config" and "%USERPROFILE%\.aws\credentials" on Windows.

If no named profile is specified, the default profile is used. Use the profile parameter or AWS_PROFILE environment variable to specify a named profile.

The locations of the shared configuration and credentials files can be configured using either the parameters shared_config_files and shared_credentials_files or the environment variables AWS_CONFIG_FILE and AWS_SHARED_CREDENTIALS_FILE.

For example:

provider "aws" {
  shared_config_files      = ["/Users/tf_user/.aws/conf"]
  shared_credentials_files = ["/Users/tf_user/.aws/creds"]
  profile                  = "customprofile"
}

Container Credentials

If you're running Terraform on CodeBuild or ECS and have configured an IAM Task Role, Terraform can use the container's Task Role. This support is based on the underlying AWS_CONTAINER_CREDENTIALS_RELATIVE_URI and AWS_CONTAINER_CREDENTIALS_FULL_URI environment variables being automatically set by those services or manually for advanced usage.

If you're running Terraform on EKS and have configured IAM Roles for Service Accounts (IRSA), Terraform can use the pod's role. This support is based on the underlying AWS_ROLE_ARN and AWS_WEB_IDENTITY_TOKEN_FILE environment variables being automatically set by Kubernetes or manually for advanced usage.

Instance profile credentials and region

When the AWS Provider is running on an EC2 instance with an IAM Instance Profile set, the provider can source credentials from the EC2 Instance Metadata Service. Both IMDS v1 and IMDS v2 are supported.

A custom endpoint for the metadata service can be provided using the ec2_metadata_service_endpoint parameter or the AWS_EC2_METADATA_SERVICE_ENDPOINT environment variable.

Assuming an IAM Role

If provided with a role ARN, the AWS Provider will attempt to assume this role using the supplied credentials.

Usage:

provider "aws" {
  assume_role {
    role_arn     = "arn:aws:iam::123456789012:role/ROLE_NAME"
    session_name = "SESSION_NAME"
    external_id  = "EXTERNAL_ID"
  }
}

Hands-on: Try the Use AssumeRole to Provision AWS Resources Across Accounts tutorial.

Assuming an IAM Role Using A Web Identity

If provided with a role ARN and a token from a web identity provider, the AWS Provider will attempt to assume this role using the supplied credentials.

Usage:

provider "aws" {
  assume_role_with_web_identity {
    role_arn                = "arn:aws:iam::123456789012:role/ROLE_NAME"
    session_name            = "SESSION_NAME"
    web_identity_token_file = "/Users/tf_user/secrets/web-identity-token"
  }
}

Using an External Credentials Process

To use an external process to source credentials, the process must be configured in a named profile, including the default profile. The profile is configured in a shared configuration file.

For example:

provider "aws" {
  profile = "customprofile"
}
[profile customprofile]
credential_process = custom-process --username jdoe
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