An instance ID is a form of metadata used to configure or manage the running instance. With this data, users can track and maintain records of things like logins and lengths of sessions. Dynamic and user data are also helpful for these processes.
Metadata about each session is stored at a constant IP address. Users can access the latest metadata by having the program use the cURL tool at the following address:
This will allow the user to see the instance ID. Other forms of metadata such as instance type and a list of public keys are available with other addresses, or without specifying the type at the end of the URL, and allowing the full list of metadata to come up.