Orchestrating Zero-Downtime Deployments With Temporal

Zero-downtime deployment is often described as a rollout strategy, but in production, it is more accurately a coordination problem. Traffic must remain on healthy instances while new ones warm up, controllers must wait for readiness before shifting load, and promotion must stop cleanly when metrics degrade. Kubernetes rolling updates already replace Pods incrementally and wait for new instances to start before removing old ones, while readiness probes determine when a Pod should receive traffic.