Just a user story with some acceptance criteria is not enough when estimating stories that you implement in AWS cloud
Scrum way of doing things delays lots of design decisions into planning I - When you work with software defined infrastructure, you need to do a design earlier in the process on, in order to get results that match with reality.
Software defined infrastructure vs. given infrastructure
When Scrum and user stories were invented, infrastructure was a given thing and features assumed it to be. At some point in time, a server was purchased or rented and this was a given set of ressources then.