ITGSS Certified DevOps Engineer Practice Test

What core component of Kubernetes is responsible for controlling the state of the cluster?

1. kube-controller-manager

2. kube-proxy

3. kube-scheduler

4. etcd

The correct answer is: kube-controller-manager

The kube-controller-manager is the core component of Kubernetes that oversees the state of the cluster. It is responsible for maintaining the desired state as defined within the cluster. This includes managing tasks such as maintaining the number of replicas in a Deployment, ensuring that nodes are in the correct state, monitoring system health, responding to events in the cluster, and making adjustments as needed to align the actual state back to the desired state. The kube-controller-manager runs controller processes that regulate the state of the cluster, making it pivotal for ensuring that the cluster operates smoothly and meets the defined configurations and policies. Its continuous monitoring and corrective actions enable Kubernetes to deliver the highly available and resilient environments for applications that it is known for. In contrast, the kube-scheduler is responsible for scheduling pods onto nodes based on resource availability and other constraints, but it does not maintain the cluster's overall state. Kube-proxy manages network routing and load balancing for services but is not involved in controlling the cluster's status. Etcd, which is a distributed key-value store, stores the state of the cluster but does not manage or control it; rather, it serves as a data source for the other components to read from or write to.