05 / Checklists
A calm sequence for the first ten minutes.
Focused incident checklists that identify safe evidence, false assumptions, stop conditions, and proof-of-fix criteria.
Authentication cookie debugging checklist
A focused checklist for engineers when the browser fails to persist or send the session cookie required by the server. The guide sequences DevTools observation, Set-Cookie attribute analysis, storage boundary inspection, and request/response correlation so each competing cause—SameSite, Secure, Path/Domain, expiration, size, and client blocking—can be ruled in or out with named evidence.
Open guide →Cache consistency debugging checklist
Investigate and resolve cache consistency failures where readers observe values that disagree with the source of truth. This checklist covers stale-read detection, TTL verification, invalidation boundary tracing, and regression checks grounded in HTTP Cache-Control semantics.
Open guide →CI-only failure debugging checklist
A diagnostic checklist for CI-only test failures where the pipeline check passes locally on a developer's machine but fails inside the remote runner. The guide frames the runner as a separate boundary with its own OS image, filesystem state, secrets, and environment, and walks through ordered triage steps to localize the divergence before changing code.
Open guide →Container network debugging checklist
A practical Docker container network debugging checklist for the failure mode "a container cannot reach the intended service or is reached on the wrong address." It sequences a triage from a single failing container outward to network driver, DNS, and published-port boundaries, with concrete commands and observable pass/fail criteria at each step. The guide emphasizes evidence-conditional decisions rather than generic advice, and uses read-only Docker commands scoped to the affected container and network.
Open guide →Database lock-wait debugging checklist
A focused PostgreSQL lock-wait debugging checklist for backend and database engineers. Walks through recognizing blocked sessions, reading pg_locks and pg_stat_activity safely, distinguishing transaction-level from tuple-level waits, identifying the blocking holder, and applying conditional, evidence-based mitigations without destructive operations.
Open guide →502 incident debugging checklist
On-call checklist for triaging HTTP 502 Bad Gateway incidents at proxy or load balancer boundaries, with ordered evidence collection, scope isolation between client, proxy, and upstream, and conditional mitigations tied to observable proof.
Open guide →Production environment drift debugging checklist
Production environment drift is a deployment contract failure: the running service no longer matches the reviewed manifest, IaC declaration, or build artifact the release engineer signed off on. This checklist helps release engineers move from observable evidence (works in staging, fails only in production) to a verifiable cause without destructive actions, using read-only inspection of the live target, declarative drift detection, and immutable artifact digests.
Open guide →Background worker stall debugging checklist
A debugging checklist for background queue workers that begin a job but never reach a terminal state (completed or failed). Covers stall detection signals, lock lifetime boundaries, and the order of triage steps an on-call engineer should follow before attempting any fix.
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