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. Answers are hidden just after each question.

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Question 1

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

1. etcd

2. API Server

3. Controller Manager

4. Scheduler

See explanation

Correct answer: API Server

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

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Question 2

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

1. etcd

2. API Server

3. Controller Manager

4. kubelet

See explanation

Correct answer: etcd

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

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Question 3

Which Control Plane component maintains the desired state of resources?

1. API Server

2. Scheduler

3. Controller Manager

4. etcd

See explanation

Correct answer: Controller Manager

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

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Question 4

Which component assigns Pods to Worker Nodes?

1. Controller Manager

2. Scheduler

3. kubelet

4. kube-proxy

See explanation

Correct answer: Scheduler

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

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Question 5

Which component runs on every Worker Node and manages Pods?

1. kube-proxy

2. kubelet

3. Container Runtime

4. Scheduler

See explanation

Correct answer: kubelet

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

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Question 6

Which component manages networking and load balancing for Services?

1. kubelet

2. kube-proxy

3. CNI Plugin

4. API Server

See explanation

Correct answer: kube-proxy

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

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Question 7

Which consensus algorithm does etcd use for high availability?

1. Paxos

2. Raft

3. Byzantine Fault Tolerance

4. Two-Phase Commit

See explanation

Correct answer: Raft

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

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Question 8

What is the Scheduler's scheduling process?

1. Selection -> Filtering -> Scoring

2. Filtering -> Scoring -> Selection -> Bind

3. Scoring -> Filtering -> Selection

4. Bind -> Filtering -> Scoring

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.

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Question 9

Which interface allows kubelet to communicate with Container Runtimes?

1. OCI

2. CRI (Container Runtime Interface)

3. CNI

4. CSI

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.) in a uniform way.

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Question 10

Which add-on provides the internal cluster DNS service?

1. Metrics Server

2. CoreDNS

3. kube-proxy

4. CNI Plugin

See explanation

Correct answer: CoreDNS

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

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Question 11

Which Container Runtime is most commonly used in Kubernetes today?

1. Docker

2. containerd

3. rkt

4. CRI-O

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 behind the scenes.

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Question 12

What is the main role of the Controller Manager?

1. Schedule Pods on nodes

2. Maintain the desired state of resources by monitoring and correcting deviations

3. Store the cluster state

4. Manage networking

See explanation

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

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

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Question 13

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

1. Controller Manager

2. Scheduler

3. kubelet

4. API Server

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.

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Question 14

What is the primary function of kube-proxy?

1. Manage Pods on a node

2. Maintain network rules for Services and perform load balancing

3. Schedule Pods

4. Store data

See explanation

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

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

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Question 15

How many etcd instances are generally needed for high availability?

1. 1

2. 2

3. 3 or more (odd number)

4. 4

See explanation

Correct answer: 3 or more (odd number)

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

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Question 16

Which operating modes can kube-proxy use?

1. iptables only

2. iptables, IPVS, or userspace

3. IPVS only

4. userspace only

See explanation

Correct answer: iptables, IPVS, or userspace

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

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Question 17

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

1. Metrics Server

2. CoreDNS

3. Dashboard

4. Ingress Controller

See explanation

Correct answer: Metrics Server

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

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Question 18

Which protocol does etcd use for replication?

1. HTTP

2. gRPC

3. TCP

4. WebSocket

See explanation

Correct answer: gRPC

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

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Question 19

Which Control Plane component can be replicated for high availability?

1. etcd only

2. All components (API Server, etcd, Controller Manager, Scheduler)

3. API Server only

4. None, the Control Plane cannot be replicated

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.

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Question 20

Which interface allows network plugins to integrate with Kubernetes?

1. CRI

2. CNI (Container Network Interface)

3. CSI

4. OCI

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.

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Question 21

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

1. Authenticate users

2. Validate and modify requests before they are persisted to etcd

3. Schedule Pods

4. Manage secrets

See explanation

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

Explanation: Admission Controllers intercept requests after authentication and authorization to validate, modify, or reject objects before they are persisted.

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Question 22

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

1. kube-proxy only

2. kubelet

3. Container Runtime only

4. Scheduler

See explanation

Correct answer: kubelet

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

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Question 23

What is the data storage format in etcd?

1. JSON

2. Key-value store with versioning

3. Relational database

4. Document store

See explanation

Correct answer: Key-value store with versioning

Explanation: etcd is a distributed key-value store that maintains a version history, enabling watch and recovery of previous states.

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Question 24

Which Control Plane component is responsible for resource reconciliation?

1. API Server

2. Controller Manager

3. Scheduler

4. etcd

See explanation

Correct answer: Controller Manager

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

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Question 25

What is the default reconciliation frequency in controllers?

1. Every second

2. Every few seconds (typically 5-10 seconds)

3. Every minute

4. Real-time

See explanation

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

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

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Question 26

What is the role of the watch mechanism in Kubernetes?

1. Monitor performance

2. Allow components to receive real-time notifications of state changes

3. Schedule Pods

4. Manage secrets

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.

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Question 27

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

1. Metrics Server

2. Kubernetes Dashboard

3. CoreDNS

4. Ingress Controller

See explanation

Correct answer: Kubernetes Dashboard

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

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Question 28

What is the default port of the Kubernetes API Server?

1. 8080

2. 6443 (HTTPS)

3. 443

4. 8443

See explanation

Correct answer: 6443 (HTTPS)

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

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Question 29

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

1. kube-proxy

2. kubelet in collaboration with the Container Runtime

3. Scheduler

4. Controller Manager

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.

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Question 30

What is the main difference between a highly available Control Plane and a simple one?

1. The number of Worker Nodes

2. The replication of Control Plane components with a load balancer

3. The Container Runtime type

4. The Kubernetes version

See explanation

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

Explanation: An 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.

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Quiz Results

Congratulations on completing the Module 2 quiz!

Score:

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

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Next Steps

Now that you have validated your knowledge:

Module 3: Pods and Deployments
Hands-on Labs: Put the architecture into practice

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Quiz created: December 2024