externalId

A unique identifier that might be required when you assume a role in another account. If the administrator of the account to which the role belongs provided you with an external ID, then provide that value in the ExternalId parameter. This value can be any string, such as a passphrase or account number. A cross-account role is usually set up to trust everyone in an account. Therefore, the administrator of the trusting account might send an external ID to the administrator of the trusted account. That way, only someone with the ID can assume the role, rather than everyone in the account. For more information about the external ID, see How to Use an External ID When Granting Access to Your Amazon Web Services Resources to a Third Party in the IAM User Guide.

The regex used to validate this parameter is a string of characters consisting of upper- and lower-case alphanumeric characters with no spaces. You can also include underscores or any of the following characters: =,.@:/-