...

When this feature is enabled, a user's available IAM roles are automatically synched via SAML. When a user signs in to the 

Pre-requisites

• Per-user authentication to AWS has been enabled.

  Info
  NOTE: Please be sure to verify that you have deployed the required policies as part of any IAM roles in use.

  
  For more information, see Configure AWS Per-User Auth for Temporary Credentials.

• This feature is supported only for the SAML authentication method of SSO authentication native to the 

  D s platform

  .  It is not supported for any other SSO auth method. For more information, see Configure SSO for SAML. 
• AWS permissions must be defined via IAM role and made available to an identity provider that adheres to SAML standards. The SAML identity provider must be configured with a list of SAML assertions containing the IAM roles that an external user may assume.

...