Your rollout strategy affects availability, rollback speed, and infrastructure cost. Here is a concise comparison of three common approaches in Kubernetes.
Rolling update
By default, a Kubernetes Deployment gradually replaces old pods with new ones (maxUnavailable, maxSurge). Pros: simple, no second full stack. Cons: during the transition two versions coexist; if the image is bad, part of traffic may already be on the new version. Fits most stateless services with solid health checks.
Blue-green
Two full stacks (blue = live, green = candidate). Traffic cutover is one step (Service selector, Ingress, or mesh). Pros: instant rollback by switching back, clean version isolation. Cons: temporary double capacity, harder for stateful workloads. Good for critical releases with a short verification window.
Canary
Send a small percentage of traffic to the new version; increase the slice when metrics look good. Implemented via Ingress, Istio/Linkerd, Argo Rollouts, etc. Pros: limited blast radius, can tie to SLOs. Cons: needs metrics discipline and automation; full rollout takes longer. Best for high-traffic services sensitive to regressions.
How to choose
Start with rolling for typical services. Move to blue-green when you need an all-or-nothing rollback and can pay for duplication. Use canary when gradual rollout and observability matter most. Tools like Opsy help standardize deploy manifests and reduce manual YAML work regardless of strategy.