Launch in the dark first
Ship changes to shadow traffic or internal users while synthetics and logs watch for regressions. Replay real production requests to catch edge cases and dependency quirks.
Prove error rates, latency, and dependency call patterns stay within budget before exposing customers. Run through rollbacks and flag toggles during the dark phase so you trust them.
Store the dark-launch results and owners in a checklist so everyone knows what "done" means before widening exposure.
Control blast radius
Use feature flags to keep rollout slices tiny and reversible. Start with canary cohorts (employees, beta customers, low-traffic regions) before general release.
Pair rollouts with Watch.Dog alerts tied to the flag so you know when to pause. Alert on business metrics too—conversion, error budgets, and latency budgets.
Document what happens to data during partial rollout (schema changes, dual writes) so you can safely roll back if needed.
Verify before promote
Gate promotion on synthetic checks, dashboards, and a quick runbook review. Require someone to check alarms, logs, and customer support queues before flipping the flag wider.
Record rollout decisions so future incidents have context on past changes. Include timestamps, owners, and what "good" looked like when you promoted.
Pause deploys that coincide with other risky events (big traffic days, dependency migrations) to avoid stacked incidents.
Measure success
Track how many incidents were caught during dark launch versus after full rollout. Use that data to tune your exposure steps and flag defaults.
Retire dark-launch flags once the feature is stable to keep your control panel lean.