VCP-VMC 2024 Question 104
Select 2An organization is deploying a Kubernetes cluster on VMware Cloud and wants to understand the role of key Kubernetes components during application deployment. Which Kubernetes components are primarily responsible for ensuring that the desired state of a deployed application is maintained?
- A
Kube-scheduler
- B
Kube-controller-manager
- C
Kube-apiserver
- D
Kubelet
- E
Etcd
Show answer and explanation
Correct answers: B, D
Explanation
In Kubernetes, maintaining the desired state of an application is a key responsibility of the kube-controller-manager and the kubelet. The kube-controller-manager ensures that the application meets the desired specifications, such as the number of replicas, while the kubelet ensures that the application is running as intended on each node. Other components, like the kube-scheduler and etcd, play important but different roles in the Kubernetes architecture.
- A. Incorrect.
The kube-scheduler is responsible for scheduling pods to nodes based on resource availability and policies. While critical for initial pod placement, it does not actively ensure the desired state of the application once scheduled.
- B. Correct.
The kube-controller-manager runs controllers like the ReplicaSet and Deployment controllers, which monitor the cluster to ensure the desired state, such as the number of replicas, is maintained.
- C. Incorrect.
The kube-apiserver is the front end for the Kubernetes control plane, handling REST requests and communication with other components. It is not directly responsible for maintaining the desired state but facilitates interactions between components.
- D. Correct.
The kubelet runs on each node and ensures that containers are running as specified in the PodSpecs provided to it. It works closely with the control plane to maintain the desired state at the node level.
- E. Incorrect.
Etcd is the distributed key-value store used by Kubernetes to store all cluster data, including configurations and desired states. However, it does not actively enforce the desired state but stores the data used by other components for this purpose.