I Froze a TCP Connection for 10 Minutes and Migrated It to Another Server

Spot instances are 80% cheaper, but AWS kills them with a 2-minute warning. If you are running stateless web requests, that’s fine. But if you are running modern LLM reasoning workloads—where a single request can take minutes to process—a 2-minute warning is a death sentence. Losing a node means losing gigabytes of computed KV Cache and instantly snapping the client's connection. User experience goes to zero. I wanted to fix this. Demo recorded on localhost with ZENO_MOCK_GPU=1. Real cross-machi