Control plane components (API server, scheduler, controller manager, etcd) in Kubernetes - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the role of the Kubernetes API server in the control plane?

The API server acts like the front desk of Kubernetes. It receives all requests from users or components, validates them, and updates the cluster state accordingly. It is the central point for communication.

beginner

What does the Kubernetes scheduler do?

The scheduler decides which worker node will run a new pod. It looks at resource availability and constraints to place pods efficiently.

beginner

Explain the purpose of the controller manager in Kubernetes.

The controller manager runs background tasks that keep the cluster healthy. It watches the cluster state and makes changes to reach the desired state, like starting or stopping pods.

beginner

What is etcd and why is it important in Kubernetes?

etcd is a key-value store that saves all the cluster data. It acts like a reliable notebook where Kubernetes stores the current state and configuration of the cluster.

intermediate

How do the control plane components work together?

The API server receives requests and updates etcd. The scheduler assigns pods to nodes. The controller manager ensures the cluster matches the desired state. etcd stores all data. Together, they keep the cluster running smoothly.

Which component acts as the main communication hub in Kubernetes control plane?

A etcd

B Scheduler

C Controller manager

D API server

The API server is the central point that handles all communication and requests in the Kubernetes control plane.

What does the Kubernetes scheduler primarily do?

A Stores cluster data

B Assigns pods to nodes

C Runs background controllers

D Validates API requests

The scheduler decides which node will run a pod based on resource availability.

Which component ensures the cluster state matches the desired configuration by running controllers?

A Controller manager

B API server

C Scheduler

D etcd

The controller manager runs controllers that watch and adjust the cluster state.

Where does Kubernetes store all its cluster state data persistently?

A Controller manager

B Scheduler

C etcd

D API server

etcd is the persistent key-value store for all cluster data.

Which component validates and processes REST requests in Kubernetes?

A API server

B Controller manager

C Scheduler

D etcd

The API server validates and processes REST API requests from users and components.

Describe the main functions of each Kubernetes control plane component: API server, scheduler, controller manager, and etcd.

Think of the control plane as a team where each member has a specific job to keep the cluster healthy.

Explain how the Kubernetes control plane components work together to manage the cluster.

Imagine a workflow where requests come in, data is saved, pods are assigned, and the system self-corrects.