Which statement best describes the RollingUpdate strategy in Kubernetes Deployments?

• A. To incrementally update pods with a new version while maintaining availability.
• B. To replace all pods at once.
• C. To scale pods down to zero.
• D. To delete the deployment.

Answer: (A)

RollingUpdate updates pods gradually, replacing old pods with new ones one by one while keeping the service available throughout the process. Kubernetes accomplishes this by creating new pods with the updated version, waiting for them to become ready, and then terminating old pods, repeating until all are updated. This approach preserves availability because a portion of the old pods remains serving traffic while the new pods come online. The behavior is controlled by settings like maxUnavailable (how many pods can be down during the update) and maxSurge (how many extra pods can run temporarily). For example, with a deployment of five replicas and default RollingUpdate settings, you might briefly run six pods during the update and never have fewer than four available pods, ensuring continuous service. This is in contrast to replacing all pods at once, scaling down to zero, or deleting the deployment, which would disrupt service or remove the workload management.