A transit-authority portal stores each clerk’s session only as files on one back-end worker’s local disk while a load balancer can send the next request to any instance. What design change restores free fan-out?
Select an answer to reveal the explanation.
Short Explanation
Local session files glue a clerk to one machine—like a locker that only one gym branch can open. A shared session store or a token unpins them so the next hop can land anywhere. That is what lets you add or remove workers freely.
Full Explanation
Load balancing only works when the next request can land on any healthy copy. Exclusive session files on local disk pin the user to one process and break scale-out. Externally stored sessions or a tokenized, stateless design restore mobility across instances. The fix is session locality design, not forever sticky routing or baking private files into images.