Backend & systems·Scaling and load management
you pin each user to the same instance so the state cached in that process is still there on their next request.
Session affinity
Also calledsticky sessions
Routing a client's requests consistently to one backend. It makes in-process state usable, which is sometimes the only practical option for WebSockets or large session data. It also breaks even load distribution, prevents clean draining on deploy, and turns one instance's death into a visible failure for a subset of users.