Run the health checks baseline

Code the narrow path that serves cluster operator during vector DB maintenance window: accept → authorize/normalize → call dependency → validate → record. Keep stages named so a trace can show which boundary passed. Success must emit evidence useful to restart_count == 0 during dep outage and ready_pods ≥ 1 when deps healthy, not only a 200 with prose. Predict the observable for GET /livez and GET /readyz before running: vector pause → readyz 503, livez 200, no restart loop; process deadlock → livez fails → restart.

Drive the path with recording fakes or local stubs. Assert call order and arguments. Idempotency keys or stable ids should keep retries from duplicating costly work where the product requires it. Product under test remains Kubernetes liveness vs readiness for retrieval-and-generation API — resist adding unrelated features mid-path.

For Health check lab, paste the CLI/HTTP transcript beside your prediction for GET /livez and GET /readyz. If the oracle is unmet (vector pause → readyz 503, livez 200, no restart loop; process deadlock → livez fails → restart), stop and debug this page; do not compensate with prompt folktales. Re-run once after a clean process start to catch hidden global state that would invalidate PROBE-RESTART-STORM-8.

Performance sketch: measure local p95 for the fake-backed path so later regressions are obvious. Keep concurrency modest until failure-handling proves limits. Log a single structured event per success with request id, revision, and the evidence field behind restart_count == 0 during dep outage and ready_pods ≥ 1 when deps healthy. Avoid hidden global caches in the happy path unless the lab is about caching — and even then key by tenant. If the path calls a model, pin model id in config and echo it in the response for auditability. Remember cluster operator during vector DB maintenance window experiences wall-clock time, not your debugger’s single-step comfort.

Prefer explicit function names over a single god-object handleRequest. Thread a correlation id from ingress to the last log line. When streaming, define what partial failure means before coding. Snapshot one successful response body in fixtures after redaction. If the path writes to a queue, assert message attributes in the fake. Stop adding retries on this page; that is the next concern. In this chapter the product is Kubernetes liveness vs readiness for retrieval-and-generation API, the human stakeholder is cluster operator during vector DB maintenance window, and the incident id you design against is PROBE-RESTART-STORM-8. Re-state the oracle in your notes — vector pause → readyz 503, livez 200, no restart loop; process deadlock → livez fails → restart — and keep the invariant visible: /livez only checks process; /readyz checks vector+model deps; wrong probe kills healthy pods. Track restart_count == 0 during dep outage and ready_pods ≥ 1 when deps healthy as the scoreboard. Surface under change control: GET /livez and GET /readyz. If you only have forty minutes, finish the fixture for readyz embedded in liveness → restart storm during dependency blip before polishing UI. Promotion language stays ternary: promote, hold, or roll back based on evidence, not hope.