How to Achieve Zero-Downtime Application with Kubernetes

In a production environment using container images, it's crucial to maintain control over image registries to avoid reliance on external sources that might become unavailable or non-compliant with security standards. To address this, solutions such as syncing images to a private registry are recommended, as demonstrated by Qovery's use of Dregsy for image deployment. Ensuring high availability in Kubernetes involves deploying a minimum of two pods, using PodDisruptionBudgets to maintain application uptime, and employing deployment strategies such as RollingUpdate for smooth transitions. Automatic rollback and properly configured probes like Liveness and Readiness are essential for minimizing downtime by ensuring applications are healthy and responsive. Challenges such as initial boot time delays, graceful termination periods, and resource management are addressed by configuring settings like initialDelaySeconds, terminationGracePeriodSeconds, and autoscaling. Pod Anti-affinity is advised to prevent placing multiple instances on the same node, reducing the risk of downtime due to node failures. Proper configuration of these elements, along with handling SIGTERM signals and ensuring sufficient resources, is vital for leveraging Kubernetes' capabilities and achieving a seamless, cloud-native application experience.