Scaling & Reliability

Compare blue-green, canary, and rolling deployments. When would you choose each?

Rolling replaces instances gradually, blue-green switches all traffic between two full environments at once, and canary sends a small slice of real traffic to the new version while watching metrics. They differ mainly in rollback speed, cost, and how much confidence you gain before full exposure.

A service depends on a database that goes down for 60 seconds. Which probe configuration behaves correctly?

Readiness controls whether a pod receives traffic; liveness controls whether it gets killed and restarted. Checking a downstream dependency in a liveness probe turns a brief dependency blip into a cluster-wide restart storm.