EC2 > Structures > UserData UserData¶ Structure Class¶ UserData dataclass ¶ Bases: _SerdeShape Describes the user data for an instance. Attributes¶ data class-attribute instance-attribute ¶ data: str | None = ... The user data. If you are using an Amazon Web Services SDK or command line tool, Base64-encoding is performed for you, and you can load the text from a file. Otherwise, you must provide Base64-encoded text.