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Running production: reliability, observability, performance and security · Proficient · Lesson 69 of 98 · 10 min video, then about 6 hours of practice
Safe deployments: rolling, blue-green, canary and feature flags
After this you can choose a deployment strategy and use feature flags to release changes gradually and roll back quickly.
Why it matters
Most outages are caused by changes. The defence is making each change small, gradual and reversible: canary releases expose a change to a few users first, feature flags separate deploying code from releasing behaviour, and every deploy has a tested rollback. Also learn expand-and-contract for database migrations, so a schema change never requires a coordinated big-bang deploy. Trap: feature flags that never get removed. Every flag is a branch in your code; clean them up.
How to use this resource
The five common deployment strategies and their trade-offs.