Is a ReplicaSet required when using Deployment in Kubernetes?

In Kubernetes, Deployment manages a ReplicaSet, which in turn manages a set of Pods. When creating a Deployment, a ReplicaSet is automatically created to ensure the desired number of replicas.

Thus, having a ReplicaSet is mandatory when using Deployment, but you usually do not create a ReplicaSet manually — this is handled by the Deployment.

If you create a Pod directly, a ReplicaSet is not needed, but then you lose the benefits of automatic replica management and updates.