Certified Kubernetes Application Developer (CKAD) Practice Test

A ReplicaSet in Kubernetes is fundamentally defined by its role in ensuring that a specified number of pod replicas are running at any given time. This means that if some pods fail or are deleted, the ReplicaSet controller will automatically create new pods to maintain the desired count. This self-healing capability is a key feature of ReplicaSets, making them essential for maintaining the availability and reliability of applications deployed in a Kubernetes cluster.

While other options describe important components of Kubernetes, they do not accurately reflect the primary function of a ReplicaSet. Automatic scaling of pods is typically the responsibility of a Horizontal Pod Autoscaler, which adjusts the number of pods based on resource metrics. Traffic routing to multiple pods is managed by Services in Kubernetes, which provide stable endpoints to direct client requests. Managing the storage of container images falls under container registries, which are separate from ReplicaSet functionality. Thus, the specific role of maintaining a desired state of pod replicas distinctly characterizes a ReplicaSet.