KCNA Practice Test 9 — 10 Questions

Question 1

Which Kubernetes controller ensures that a specified number of pod replicas are running at all times?

Accepted Answer

ReplicaSet. A ReplicaSet is the Kubernetes controller that ensures a specified number of pod replicas are running at all times. It uses a label selector to match pods and maintains the desired replica count by creating or deleting pods as needed. ReplicaSet is the successor to ReplicationController and is primarily used by Deployments to manage pod scaling and self-healing.

Answer

Job

Answer

ReplicationController

Answer

DaemonSet

Question 2

Which TWO of the following are required fields when defining a container in a Kubernetes Pod spec? (Choose 2)

Accepted Answer

image. In a Kubernetes Pod spec, the `name` and `image` fields are mandatory for each container definition. The `name` field uniquely identifies the container within the Pod, and the `image` field specifies the container image to run (e.g., `nginx:1.25`). Without these two fields, the Pod creation will fail with a validation error from the Kubernetes API server.

Answer

env

Answer

resources

Answer

ports

Question 3

A DevOps engineer has created a ConfigMap named 'app-config' with some configuration data. They want to make that data available as environment variables in a pod. Which field in the pod spec should they use to achieve this?

Accepted Answer

spec.containers[].envFrom. The `envFrom` field in the container spec allows you to inject all key-value pairs from a ConfigMap (or Secret) as environment variables into the container. This is the most direct and efficient way to expose ConfigMap data as environment variables without needing to specify each key individually.

Answer

spec.volumes

Answer

spec.containers[].volumeMounts

Answer

spec.containers[].env

Question 4

Which TWO components are part of a Kubernetes worker node?

Accepted Answer

kubelet. The kubelet is the primary node agent that runs on every worker node. It registers the node with the cluster, receives Pod specifications from the API server, and ensures that the containers described in those Pods are running and healthy. Without the kubelet, a node cannot participate in the cluster as a worker.

Answer

kube-scheduler

Answer

container runtime

Answer

etcd

Question 5

Which of the following is NOT a responsibility of the kubelet on a worker node?

Accepted Answer

Implementing network rules for Services. The kubelet is the primary node agent that runs on each worker node, responsible for ensuring containers are running in a Pod as specified by the PodSpec. It performs liveness and readiness probes, starts and stops containers, and reports node and pod status to the control plane. Implementing network rules for Services, such as iptables or IPVS rules, is the responsibility of the kube-proxy, not the kubelet.

Answer

Performing liveness and readiness probes

Answer

Starting and stopping containers based on PodSpecs

Answer

Reporting node and pod status to the control plane

Question 6

A development team wants to deploy a serverless function that triggers when a file is uploaded to an S3 bucket. Which cloud native technology is most appropriate for this scenario?

Accepted Answer

Knative. Knative is a Kubernetes-based platform to build, deploy, and manage serverless workloads, including event-driven functions. AWS Lambda is a proprietary service, not a cloud native project.

Answer

AWS Lambda

Answer

Helm

Answer

Istio

Question 7

When using a Service of type ClusterIP, how do pods reach the service?

Accepted Answer

Via the service's cluster IP and port. A Service of type ClusterIP exposes a stable virtual IP (the cluster IP) and port within the cluster. Pods reach the Service by sending traffic to this cluster IP and port, which is then load-balanced by kube-proxy (using iptables, IPVS, or eBPF rules) to one of the backing pod endpoints. This is the default and most fundamental Service type in Kubernetes.

Answer

Via the node's IP address and a high port

Answer

Via an external load balancer

Answer

Directly via the pod's IP address

Question 8

Your organization runs a cloud-native e-commerce platform on Kubernetes. The platform consists of several microservices: a frontend service, an order service, a payment service, and a shipping service. All services communicate via HTTP REST APIs. Recently, during a flash sale event, the platform experienced a cascading failure. The order service became overwhelmed with requests and started responding slowly. This caused the frontend service to time out waiting for order responses, and eventually the frontend service crashed due to exhausted thread pools. The payment and shipping services were unaffected because they are called asynchronously via a message queue. You need to redesign the system to prevent such cascading failures in the future. Which approach is the most effective?

Accepted Answer

Implement circuit breakers in the frontend service for calls to the order service. Implementing circuit breakers in the frontend service for calls to the order service prevents cascading failures by monitoring failure rates and automatically tripping the circuit when the order service becomes slow or unresponsive. This stops the frontend from exhausting its thread pools waiting for timeouts, allowing it to fail fast and return a fallback response. Circuit breakers are a proven resilience pattern in cloud-native architectures, especially for synchronous HTTP REST calls where latency spikes can propagate.

Answer

Scale up the frontend service to handle more concurrent requests

Answer

Convert all inter-service communication to synchronous calls with retries

Answer

Increase the timeout values in the frontend service configuration

Question 9

Which TWO of the following are deployment patterns that can be used to update applications with minimal downtime? (Choose two.)

Accepted Answer

Blue-green deployment. Blue-green and canary are deployment patterns that reduce downtime by gradually shifting traffic. Rolling update is also a pattern but the question asks for minimal downtime; blue-green and canary are specifically designed for that.

Answer

DaemonSet deployment

Answer

Sidecar deployment

Answer

Recreate deployment

Question 10

Which TWO of the following are core principles of cloud native architecture? (Choose two.)

Accepted Answer

Containerization. Containerization (Option D) is a core principle of cloud native architecture because it packages applications and their dependencies into isolated, lightweight containers, enabling consistent deployment across environments and efficient resource utilization. This aligns with the cloud native goal of portability and scalability, as containers can be orchestrated by platforms like Kubernetes to manage dynamic workloads.

Answer

Manual infrastructure provisioning

Answer

Monolithic application design

Answer

Tight coupling between services