Blue-greenCanary
HowRun two identical environments; switch all traffic at onceSend a few users to the new version, then increase
RollbackInstant: switch backFast: move traffic back
RiskAll users move togetherOnly a few users see a bad release
CostDouble infrastructure during the releaseLittle extra capacity
Best forSimple, all-or-nothing releasesBusy apps with good monitoring
Either way
Automate it, and watch your metrics during the rollout.
Tools that do this
Argo Rollouts, AWS CodeDeploy, Flagger and service meshes like Istio.
Why it matters for your career
Safe release strategies are a favourite DevOps and SRE interview topic, and a daily reality on busy production systems.
