httpTokens

The state of token usage for your instance metadata requests. If the parameter is not specified in the request, the default state is optional.

If the state is optional, you can choose to retrieve instance metadata with or without a signed token header on your request. If you retrieve the IAM role credentials without a token, the version 1.0 role credentials are returned. If you retrieve the IAM role credentials using a valid signed token, the version 2.0 role credentials are returned.

If the state is required, you must send a signed token header with any instance metadata retrieval requests. In this state, retrieving the IAM role credentials always returns the version 2.0 credentials; the version 1.0 credentials are not available.