---
layout: docs
page_title: Vault Auto-Auth AWS Method
description: AWS Method for Vault Auto-Auth
---

# Vault Auto-Auth AWS method

The `aws` method performs authentication against the [AWS Auth
method](/vault/docs/auth/aws). Both `ec2` and `iam`
authentication types are supported. If `ec2` is used, the agent will store the
reauthentication value in memory and use it for reauthenticating, but will not
persist it to disk.

Due to the complexity of the Trust On First Use (TOFU) model used in the `ec2`
method, we recommend the `iam` method when possible.

## Credentials

Vault will use the AWS SDK's normal credential chain behavior, which means it
will use the first valid credentials it finds in the following order:

1. A static credential configuration
2. Environment variables
3. A file containing credentials
4. From any identity services available in its physical environment like container environment variables or role-based instance metadata

Wherever possible, we recommend using identity services (method 4) for credentials.
These rotate regularly and require no effort on your part to provision, making
identity services the most secure of the four methods. If using identity services _and_ a custom
`credential_poll_interval`, be sure the frequency is set low enough to pick up new credentials
from the physical environment as they become available.

To use identity services, choose the `iam` type and leave the `access_key`, `secret_key`, and `session_token`
parameters unset in your configuration.

## Configuration

- `type` `(string: required)` - The type of authentication; must be `ec2` or `iam`.

- `role` `(string: required)` - The role to authenticate against on Vault.

- `credential_poll_interval` `(integer: optional)` - In seconds, how frequently the Vault agent should check for new credentials if using the iam type.

- `access_key` `(string: optional)` - When using static credentials, the access key to use.

- `secret_key` `(string: optional)` - When using static credentials, the secret key to use.

- `region` `(string: "us-east-1")` - The region to use for signing the authentication request. The
  region Agent uses should match that corresponding to
  [`sts_endpoint`](/vault/api-docs/auth/aws#sts_endpoint),
  if a custom endpoint has been configured on the Vault server.

- `session_token` `(string: optional)` - The session token to use for authentication, if needed.

- `header_value` `(string: optional)` - If configured in Vault, the value to use for
  [`iam_server_id_header_value`](/vault/api-docs/auth/aws#iam_server_id_header_value).

- `nonce` `(string: optional)` - If not provided, Vault will generate a new UUID every time `vault agent` runs.
  If set, make sure you understand the importance of generating a good, unique `nonce` and protecting it.
  See [Client Nonce](/vault/docs/auth/aws#client-nonce) for more information.

## Tutorial

Refer to the [Vault Agent with
AWS](/vault/tutorials/vault-agent/agent-aws) tutorial to learn how to integrate Vault Agent with IAM AWS' native authentication.
