KCNA Timed Practice Test 5 — 10 Questions

Question 1

When creating a Deployment, you want to ensure that only a certain number of pods run at a time across all nodes. Which field in the Deployment spec controls this?

Accepted Answer

spec.replicas. The `spec.replicas` field in a Deployment spec defines the desired number of identical Pod replicas that should be running at any given time. This field directly controls the count of Pods across all nodes in the cluster, ensuring that exactly that many Pods are maintained by the ReplicaSet controller. Option A is correct because it is the only field that sets the target Pod count.

Answer

spec.selector

Answer

spec.minReadySeconds

Answer

spec.template

Question 2

Which component is responsible for running containers on a Kubernetes node?

Accepted Answer

Container runtime (e.g., containerd). The container runtime (e.g., containerd) is the component responsible for actually running containers on a Kubernetes node. It pulls container images, manages container lifecycles, and handles low-level operations such as starting and stopping containers via the CRI (Container Runtime Interface). Without a container runtime, the kubelet cannot launch or manage any containers on the node.

Answer

etcd

Answer

kube-scheduler

Answer

kubelet

Question 3

What is the role of etcd in a Kubernetes cluster?

Accepted Answer

It stores cluster state and configuration. etcd is a distributed, consistent key-value store that serves as Kubernetes' primary datastore for all cluster state and configuration data. It stores objects like pods, services, deployments, secrets, and configmaps, and is the source of truth for the entire cluster. The Kubernetes API server is the only component that communicates directly with etcd, ensuring strong consistency via the Raft consensus protocol.

Answer

It serves as the container runtime

Answer

It provides DNS-based service discovery

Answer

It schedules pods onto nodes

Question 4

A pod has resource requests of 512Mi memory and 500m CPU, and limits of 1Gi memory and 1 CPU. The node has 4Gi memory and 2 CPU cores. If the pod tries to use 700m CPU, what will happen?

Accepted Answer

The pod will be allowed to use 700m CPU. The pod's CPU request is 500m, and its CPU limit is 1 CPU (1000m). When the pod attempts to use 700m CPU, it is below the limit of 1000m, so it is allowed to burst up to that amount. Kubernetes uses the CPU request for scheduling and the limit for throttling; since 700m is within the limit, no throttling occurs. The pod is not evicted or terminated because it has not exceeded its memory limit or violated any resource constraints.

Answer

The pod will be throttled to 500m CPU

Answer

The pod will be evicted from the node

Answer

The pod will be terminated for exceeding the limit

Question 5

Which of the following is a key principle of microservices architecture?

Accepted Answer

Loose coupling and independent deployability. Microservices architecture emphasizes decomposition of an application into small, independently deployable services that communicate over well-defined APIs. Option B is correct. Option A describes a monolith; Option C is not a principle; Option D refers to containerization.

Answer

Shared database schema for all services

Answer

Tight coupling between services

Answer

Building a large, monolithic codebase

Question 6

You need to deploy a batch job that processes a queue and runs to completion. The job should run exactly once and create exactly one pod per work item, but some items may fail. Which Kubernetes resource is best suited?

Accepted Answer

Job. A Job with a specified number of completions and parallelism can run pods to completion, handling failures by restarting or marking as failed.

Answer

Deployment

Answer

CronJob

Answer

DaemonSet

Question 7

Which of the following best describes a key advantage of containers over virtual machines?

Accepted Answer

Containers share the host OS kernel, resulting in lower resource overhead compared to VMs. Option A is correct. Containers share the host OS kernel, making them more lightweight than VMs, which each include a full guest OS. Option B is false — containers share the host kernel. Option C is false — resource usage is lower for containers. Option D is false — VMs typically take longer to start.

Answer

Containers take longer to start than VMs because they need to initialize a kernel

Answer

Containers consume more disk space than VMs because they include a full operating system

Answer

Containers have stronger isolation than VMs because each container runs its own kernel

Question 8

Which TWO statements about Docker Compose and Kubernetes are correct?

Accepted Answer

Kubernetes provides built-in auto-scaling and self-healing capabilities. Options A and D are correct. Docker Compose is primarily for single-host container orchestration (A). Kubernetes provides built-in features like auto-scaling and self-healing (D). Option B is false — Kubernetes can also be used in production. Option C is false — Docker Compose does not manage a cluster; it uses a single Docker daemon. Option E is false — Docker Compose uses a compose file, not YAML manifests? Actually both use YAML, but the statement is misleading; Compose uses docker-compose.yml, Kubernetes uses YAML manifests, but they are not interchangeable.

Answer

Kubernetes is only used in production environments

Answer

Docker Compose and Kubernetes use the same YAML manifest format

Answer

Docker Compose supports multi-node clustering out-of-the-box

Question 9

A pod is stuck in 'Pending' state. You run 'kubectl describe pod mypod' and see the event '0/4 nodes are available: 4 Insufficient cpu'. What is the most likely cause?

Accepted Answer

None of the nodes have enough CPU resources to satisfy the pod's request. The scheduler cannot place the pod because no node has enough available CPU to meet the pod's request.

Answer

The pod has exceeded its memory limit

Answer

The pod's image pull is failing

Answer

The pod's liveness probe is failing

Question 10

A pod is in CrashLoopBackOff. You check the logs and see 'Error: container process not found'. What is the most likely cause?

Accepted Answer

The container's entrypoint or command is incorrect. The container's entrypoint or command may be misconfigured, causing the container to exit immediately.

Answer

The pod has insufficient memory

Answer

The liveness probe is misconfigured

Answer

The container image is missing