Which control plane component is responsible for running controllers that regulate cluster state?

Which control plane component is responsible for running controllers that regulate cluster state?

• A. Controller Manager
• B. Scheduler
• C. API server
• D. Kubelet

Answer: (A)

Controllers are the processes that continuously work to move the cluster toward the desired state defined by the user. The component that hosts and runs these controller loops is the Controller Manager. It manages various controllers—like those ensuring the correct number of replicas, keeping endpoints in sync, and maintaining node health—and watches the API server for changes to resources, then takes actions to align the actual state with the desired state. The scheduler, by contrast, is responsible for deciding which node will run a given pod, based on resource availability and constraints. The API server is the gateway for all API interactions and stores state in etcd. The Kubelet runs on each node to manage containers and node-level work. Thus, the Controller Manager is the part that runs controllers regulating cluster state.

Controllers are the processes that continuously work to move the cluster toward the desired state defined by the user. The component that hosts and runs these controller loops is the Controller Manager. It manages various controllers—like those ensuring the correct number of replicas, keeping endpoints in sync, and maintaining node health—and watches the API server for changes to resources, then takes actions to align the actual state with the desired state.

The scheduler, by contrast, is responsible for deciding which node will run a given pod, based on resource availability and constraints. The API server is the gateway for all API interactions and stores state in etcd. The Kubelet runs on each node to manage containers and node-level work. Thus, the Controller Manager is the part that runs controllers regulating cluster state.