AWS Provider

The Amazon Web Services (AWS) provider is used to interact with the many resources supported by AWS. The provider needs to be configured with the proper credentials before it can be used.

Use the navigation to the left to read about the available resources.

Example Usage

# Configure the AWS Provider
provider "aws" {
    access_key = "${var.aws_access_key}"
    secret_key = "${var.aws_secret_key}"
    region = "us-east-1"
}

# Create a web server
resource "aws_instance" "web" {
    ...
}

Authentication

The AWS provider offers flexible means of providing credentials for authentication. The following methods are supported, in this order, and explained below:

  • Static credentials
  • Environment variables
  • Shared credentials file
  • EC2 Role

Static credentials

Static credentials can be provided by adding an access_key and secret_key in-line in the aws provider block:

Usage:

provider "aws" {
  region     = "us-west-2"
  access_key = "anaccesskey"
  secret_key = "asecretkey"
}

Environment variables

You can provide your credentials via AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY, environment variables, representing your AWS Access Key and AWS Secret Key, respectively. AWS_DEFAULT_REGION and AWS_SESSION_TOKEN are also used, if applicable:

provider "aws" {}

Usage:

$ export AWS_ACCESS_KEY_ID="anaccesskey" 
$ export AWS_SECRET_ACCESS_KEY="asecretkey"
$ export AWS_DEFAULT_REGION="us-west-2"
$ terraform plan

Shared Credentials file

You can use an AWS credentials file to specify your credentials. The default location is $HOME/.aws/credentials on Linux and OSX, or "%USERPROFILE%\.aws\credentials" for Windows users. If we fail to detect credentials inline, or in the environment, Terraform will check this location. You can optionally specify a different location in the configuration by providing shared_credentials_file, or in the environment with the AWS_SHARED_CREDENTIALS_FILE variable. This method also supports a profile configuration and matching AWS_PROFILE environment variable:

Usage:

provider "aws" {
  region                   = "us-west-2"
  shared_credentials_file  = "/Users/tf_user/.aws/creds"
  profile                  = "customprofile"
}

EC2 Role

If you're running Terraform from an EC2 instance with IAM Instance Profile using IAM Role, Terraform will just ask the metadata API endpoint for credentials.

This is a preferred approach over any other when running in EC2 as you can avoid hardcoding credentials. Instead these are leased on-the-fly by Terraform which reduces the chance of leakage.

You can provide custom metadata API endpoint via AWS_METADATA_ENDPOINT variable which expects the endpoint URL including the version and defaults to http://169.254.169.254:80/latest.

Assume role

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

Usage:

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

Argument Reference

The following arguments are supported in the provider block:

  • access_key - (Optional) This is the AWS access key. It must be provided, but it can also be sourced from the AWS_ACCESS_KEY_ID environment variable, or via a shared credentials file if profile is specified.

  • secret_key - (Optional) This is the AWS secret key. It must be provided, but it can also be sourced from the AWS_SECRET_ACCESS_KEY environment variable, or via a shared credentials file if profile is specified.

  • region - (Required) This is the AWS region. It must be provided, but it can also be sourced from the AWS_DEFAULT_REGION environment variables, or via a shared credentials file if profile is specified.

  • profile - (Optional) This is the AWS profile name as set in the shared credentials file.

  • assume_role - (Optional) An assume_role block (documented below). Only one assume_role block may be in the configuration.

  • shared_credentials_file = (Optional) This is the path to the shared credentials file. If this is not set and a profile is specified, ~/.aws/credentials will be used.

  • token - (Optional) Use this to set an MFA token. It can also be sourced from the AWS_SESSION_TOKEN environment variable.

  • max_retries - (Optional) This is the maximum number of times an API call is being retried in case requests are being throttled or experience transient failures. The delay between the subsequent API calls increases exponentially.

  • allowed_account_ids - (Optional) List of allowed AWS account IDs (whitelist) to prevent you mistakenly using a wrong one (and end up destroying live environment). Conflicts with forbidden_account_ids.

  • forbidden_account_ids - (Optional) List of forbidden AWS account IDs (blacklist) to prevent you mistakenly using a wrong one (and end up destroying live environment). Conflicts with allowed_account_ids.

  • insecure - (Optional) Optional) Explicitly allow the provider to perform "insecure" SSL requests. If omitted, default value is false

  • dynamodb_endpoint - (Optional) Use this to override the default endpoint URL constructed from the region. It's typically used to connect to dynamodb-local.

  • kinesis_endpoint - (Optional) Use this to override the default endpoint URL constructed from the region. It's typically used to connect to kinesalite.

  • skip_credentials_validation - (Optional) Skip the credentials validation via STS API. Useful for AWS API implementations that do not have STS available/implemented.

  • skip_requesting_account_id - (Optional) Skip requesting the account ID. Useful for AWS API implementations that do not have IAM/STS API and/or metadata API. true (enabling this option) prevents you from managing any resource that requires Account ID to construct an ARN, e.g.

  • skip_metadata_api_check - (Optional) Skip the AWS Metadata API check. Useful for AWS API implementations that do not have a metadata API endpoint. true prevents Terraform from authenticating via Metadata API - i.e. you may need to use other auth methods (static credentials set as ENV vars or config)

  • s3_force_path_style - (Optional) set this to true to force the request to use path-style addressing, i.e., http://s3.amazonaws.com/BUCKET/KEY. By default, the S3 client will use virtual hosted bucket addressing when possible (http://BUCKET.s3.amazonaws.com/KEY). Specific to the Amazon S3 service.

The nested assume_role block supports the following:

  • role_arn - (Required) The ARN of the role to assume.

  • session_name - (Optional) The session name to use when making the AssumeRole call.

  • external_id - (Optional) The external ID to use when making the AssumeRole call.

Nested endpoints block supports the following:

  • iam - (Optional) Use this to override the default endpoint URL constructed from the region. It's typically used to connect to custom iam endpoints.

  • ec2 - (Optional) Use this to override the default endpoint URL constructed from the region. It's typically used to connect to custom ec2 endpoints.

  • elb - (Optional) Use this to override the default endpoint URL constructed from the region. It's typically used to connect to custom elb endpoints.

  • s3 - (Optional) Use this to override the default endpoint URL constructed from the region. It's typically used to connect to custom s3 endpoints.

Getting the Account ID

If you use either allowed_account_ids or forbidden_account_ids, Terraform uses several approaches to get the actual account ID in order to compare it with allowed/forbidden ones.

Approaches differ per auth providers:

  • EC2 instance w/ IAM Instance Profile - Metadata API is always used. Introduced in Terraform 0.6.16.
  • All other providers (ENV vars, shared creds file, ...) will try two approaches in the following order
    • iam:GetUser - typically useful for IAM Users. It also means that each user needs to be privileged to call iam:GetUser for themselves.
    • sts:GetCallerIdentity - Should work for both IAM Users and federated IAM Roles, introduced in Terraform 0.6.16.
    • iam:ListRoles - this is specifically useful for IdP-federated profiles which cannot use iam:GetUser. It also means that each federated user need to be assuming an IAM role which allows iam:ListRoles. Used in Terraform 0.6.16+. There used to be no better way to get account ID out of the API when using federated account until sts:GetCallerIdentity was introduced.