Lesson 1: Two copies of the server behind one address
26 min read·13 Oct 2026
Module 9 · Lesson 1 · About 45 minutes · Needs: Module 5 Lessons 1 and 2 (the packaged server); Module 2 Lessons 3 and 4 (Streamable HTTP and the two protocol eras); Module 4 Lesson 4 (multi round-trip requests)
The situation
Monday 5 October 2026, week 5. The first nap study cohort is in the sleep lab, and Priya and Tomas now reach the notes server from their own computers all day. One process is one point of failure: a restart drops everyone. You run two copies of the server behind one address.
The server is Module 5's build_server, unchanged. Two requests follow you through the lesson: Nare's question search_notes(query="nap study participants"), which should find lab-sync-2026-09-02 with a score of 3, and her write create_note("Cohort 1 started", ...). Your job is to find out which of them survive landing on a different copy each time.