Skip to main content

Quiz Module 2 - Kubernetes Architecture and Components

Instructions​

This quiz contains 30 multiple-choice questions to validate your understanding of Module 2.

Tip: Answer each question before revealing the answer. The answers are hidden just after each question.

Question 1​

What is the single entry point for all interactions with a Kubernetes cluster?

See explanation

Correct answer: API Server

Explanation: The API Server is the only component with which users and other cluster components interact directly. All requests go through the API Server.

Question 2​

Which component stores all the configuration and state of the Kubernetes cluster?

See explanation

Correct answer: etcd

Explanation: etcd is the distributed database that stores all the configuration and state of the cluster. It is the single source of truth for Kubernetes.

Question 3​

Which Control Plane component maintains the desired state of resources?

See explanation

Correct answer: Controller Manager

Explanation: The Controller Manager runs controllers that monitor the cluster's state and take actions to match the actual state to the desired state (control loop pattern).

Question 4​

Which component assigns Pods to Worker Nodes?

See explanation

Correct answer: Scheduler

Explanation: The Scheduler is responsible for assigning unscheduled Pods to appropriate nodes based on available resources, affinities, and constraints.

Question 5​

Which component runs on each Worker Node and manages the Pods?

See explanation

Correct answer: kubelet

Explanation: kubelet is the agent that runs on each Worker Node. It manages the Pods, communicates with the API Server, and performs health checks.

Question 6​

Which component manages the networking and load balancing of Services?

See explanation

Correct answer: kube-proxy

Explanation: kube-proxy maintains network rules that allow communication with Services and performs load balancing between backend Pods.

Question 7​

Which consensus algorithm does etcd use for high availability?

See explanation

Correct answer: Raft

Explanation: etcd uses the Raft consensus algorithm to ensure consistency and high availability in a distributed cluster.

Question 8​

What is the scheduling process of the Scheduler?

See explanation

Correct answer: Filtering → Scoring → Selection → Bind

Explanation: The Scheduler first filters eligible nodes, then scores them, selects the best one, and finally binds the Pod to the selected node.

Question 9​

Which interface allows kubelet to communicate with Container Runtimes?

See explanation

Correct answer: CRI (Container Runtime Interface)

Explanation: CRI is the standard interface that allows kubelet to communicate with different Container Runtimes (containerd, CRI-O, etc.) uniformly.

Question 10​

Which add-on provides the internal DNS service of the cluster?

See explanation

Correct answer: CoreDNS

Explanation: CoreDNS is the DNS service that resolves internal Service names (e.g., my-service.default.svc.cluster.local).

Question 11​

Which Container Runtime is most commonly used in Kubernetes today?

See explanation

Correct answer: containerd

Explanation: containerd has become the standard Container Runtime in Kubernetes. Docker has been deprecated as a direct runtime, although Docker Desktop uses containerd in the background.

Question 12​

What is the primary role of the Controller Manager?

See explanation

Correct answer: Maintain the desired state of resources by monitoring and correcting discrepancies

Explanation: The Controller Manager runs controllers that monitor the current state of the cluster and take actions to match the actual state to the desired state (control loop pattern).

Question 13​

Which component uses filters and scores to choose the best node for a Pod?

See explanation

Correct answer: Scheduler

Explanation: The Scheduler first filters eligible nodes, then scores them based on criteria like available resources, affinities, and constraints, before selecting the best node.

Question 14​

What is the main function of kube-proxy?

See explanation

Correct answer: Maintain network rules for Services and perform load balancing

Explanation: kube-proxy maintains network rules (iptables, IPVS, or userspace) that allow communication with Services and distributes traffic between backend Pods.

Question 15​

How many etcd instances are generally needed for high availability?

See explanation

Correct answer: 3 or more (odd number)

Explanation: etcd uses the Raft consensus which requires an odd number of instances (3, 5, 7, etc.) to ensure high availability and avoid split-brain scenarios.

Question 16​

What operating modes can kube-proxy use?

See explanation

Correct answer: iptables, IPVS, or userspace

Explanation: kube-proxy can operate in iptables mode (default), IPVS mode (more performant for many Services), or userspace mode (deprecated).

Question 17​

Which Kubernetes add-on provides resource metrics for Pods and nodes?

See explanation

Correct answer: Metrics Server

Explanation: Metrics Server collects resource metrics (CPU, memory) from nodes and Pods, enabling the use of HPA (Horizontal Pod Autoscaler) and kubectl top.

Question 18​

Which protocol does etcd use for replication?

See explanation

Correct answer: gRPC

Explanation: etcd uses gRPC for communication between cluster members, which is more efficient than HTTP for replication operations.

Question 19​

Which Control Plane component can be replicated for high availability?

See explanation

Correct answer: All components (API Server, etcd, Controller Manager, Scheduler)

Explanation: All Control Plane components can be replicated for high availability, with a load balancer in front of the API Servers.

Question 20​

Which interface allows network plugins to integrate with Kubernetes?

See explanation

Correct answer: CNI (Container Network Interface)

Explanation: CNI is the standard interface that allows network plugins (Calico, Flannel, Weave, etc.) to integrate with Kubernetes to manage Pod networking.

Question 21​

What is the role of the Admission Controller in the API Server?

See explanation

Correct answer: Validate and modify requests before they are persisted in etcd

Explanation: Admission Controllers intercept requests after authentication and authorization to validate, modify, or reject objects before their persistence.

Question 22​

Which component runs on each Worker Node and communicates with the API Server?

See explanation

Correct answer: kubelet

Explanation: kubelet is the agent that runs on each Worker Node. It communicates with the API Server to receive Pod specifications and report Pod status.

Question 23​

What is the data storage format in etcd?

See explanation

Correct answer: Key-value store with versioning

Explanation: etcd is a distributed key-value store that maintains a history of versions, allowing watch and retrieval of previous states.

Question 24​

Which Control Plane component is responsible for resource reconciliation?

See explanation

Correct answer: Controller Manager

Explanation: The Controller Manager runs controllers that monitor the current and desired states, then take actions to reconcile them (control loop pattern).

Question 25​

What is the default reconciliation frequency in controllers?

See explanation

Correct answer: Every few seconds (typically 5-10 seconds)

Explanation: Controllers reconcile periodically, usually every 5-10 seconds, to avoid system overload while maintaining responsiveness.

Question 26​

What is the role of the watch mechanism in Kubernetes?

See explanation

Correct answer: Allow components to receive real-time notifications of state changes

Explanation: The watch mechanism allows components (kubelet, controllers, etc.) to subscribe to state changes via the API Server, avoiding constant polling.

Question 27​

Which Kubernetes add-on provides a web interface to manage the cluster?

See explanation

Correct answer: Kubernetes Dashboard

Explanation: Kubernetes Dashboard is a web interface that allows you to visualize and manage cluster resources graphically.

Question 28​

What is the default port of the Kubernetes API Server?

See explanation

Correct answer: 6443 (HTTPS)

Explanation: The API Server listens on port 6443 in HTTPS by default. Port 8080 was used in insecure mode (deprecated).

Question 29​

Which component is responsible for managing the lifecycle of containers on a node?

See explanation

Correct answer: kubelet in collaboration with the Container Runtime

Explanation: kubelet receives Pod specifications from the API Server and uses the Container Runtime (via CRI) to create, start, stop, and delete containers.

Question 30​

What is the main difference between a high availability Control Plane and a single Control Plane?

See explanation

Correct answer: The replication of Control Plane components with a load balancer

Explanation: A HA Control Plane replicates all components (API Server, etcd, Controller Manager, Scheduler) across multiple machines with a load balancer in front of the API Servers to avoid single points of failure.

Quiz Result​

Congratulations on completing the Module 2 quiz!

Score:

  • 25-30 correct answers: Excellent! You master Kubernetes architecture.
  • 20-24 correct answers: Very good! Review the components where you had difficulties.
  • 15-19 correct answers: Good! Review the chapters on architecture.
  • Less than 15: Recommended to review the module before continuing.

Next Steps​

Now that you have validated your knowledge:

Module 3: Pods and Deployments
Practical Labs: Put the architecture into practice

Quiz created on: December 2024