[AlexITC]

> No one is talking about redundancy though. I love setups like this but prod environments need robust forms of redundancy

Not really, there are many kinds of apps that don't need such redundancy.

> Also, none of the solutions discussed here gracefully handle new connections on the new service while waiting for all connections to terminate before shutting down the old service. Maybe some of the more esoteric Ansible do idk.

I have dealt with this in the code with shutdown hooks on the server, waiting for existing requests to finish its processing and reject new requests, clients will just end up retrying, not all apps can accept this but many can.