What is the role of a Deployment in OpenShift, and how does it relate to ReplicaSets?

• A. A Deployment stores image streams for versions.
• B. A Deployment serves as a storage class for volumes.
• C. A Deployment exposes services to external clients.
• D. A Deployment manages a set of Pods through an associated ReplicaSet and handles rolling updates.

Answer: (D)

A Deployment provides a declarative way to manage a set of Pods by coordinating a ReplicaSet and handling rolling updates. You declare how many replicas you want, the Pod template, and how updates should be performed. The Deployment controller ensures there is a corresponding ReplicaSet for those pods. When you change the Deployment (for example, update the image), it creates a new ReplicaSet with the updated Pod template and starts a rolling update, gradually replacing old Pods with new ones while keeping the system available. If something goes wrong, you can roll back to a previous revision. In short, the Deployment manages the lifecycle and updates of Pods indirectly through a ReplicaSet, while the ReplicaSet ensures the desired number of Pod replicas are running. Deployments aren’t for storing image streams, selecting storage classes, or exposing services—those are handled by other resources.