Rolling Update
A rolling update replaces old-version instances with new ones batch by batch; both versions coexist during the update, achieving zero downtime.
Purpose
Zero-downtime progressive updates, controlling update pace and batches.
Mechanism
Batch by batch (controlled by maxSurge/maxUnavailable), create new-version instances and terminate old ones. Health checks ensure new instances are ready before proceeding. Pause the rollout on failure. The default K8s Deployment strategy.
Use cases
- Zero-downtime updates
- Progressive replacement
- K8s deployment