Game Day
A scheduled exercise in which a failure is deliberately introduced and the team responds as though it were real, to test the system and the response together.
Distinct from chaos engineering, which tests the system. A game day tests the whole sociotechnical system: the monitoring, the alerting, the runbooks, the escalation path, the communications, and whether the people who need access have it.
The consistent finding is that the technical failure is handled and everything around it is not. Teams discover the runbook is stale, the dashboard does not show the relevant metric, the on-call engineer lacks permission to perform the fix, the status page cannot be updated, or the escalation contact left the company.
Running one: pick a plausible scenario, tell people the window but not the scenario, have a facilitator and observers, define an abort condition, and run it in an environment as production- like as you can tolerate. Debrief immediately and convert findings into owned actions.
Start in pre-production. Progress to production only when pre-production stops producing findings, which usually takes longer than expected.