Zero-Downtime Deployments for Java Apps on Kubernetes

▤ Summary

This article explains how to run Java applications on Kubernetes without downtime. It walks through rolling updates, blue-green deployments, canary releases, and traffic mirroring to keep services available during rollout. It also covers Kubernetes primitives such as Deployments, Services, PodDisruptionBudgets, HPA, probes, and lifecycle hooks, plus Java framework settings for graceful shutdown. The guide shows how CI/CD tools like GitHub Actions, Jenkins, Helm, and ArgoCD support automated, safe deployments. It emphasizes externalizing session state, handling database migrations carefully, and adding observability and rollback checks to reduce deployment risk.

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