Kubernetes Fundamentals

A developer notices that when the control plane component responsible for exposing the cluster's REST interface is temporarily unavailable, kubectl commands fail and no new Pods can be created, but existing Pods keep running normally. Which control plane component are they describing?

A backend team runs three Pods created by a Deployment. Frontend Pods in the same cluster need to reach the backend reliably, but the backend Pods are frequently rescheduled, so their IP addresses keep changing. The team does not want to expose the backend outside the cluster. Which approach provides a stable internal address for the frontend to use?

A team packages a web server whose configuration must be provided as a file at /etc/app/config.yaml inside the container. The configuration content is stored in a ConfigMap named app-config under the key config.yaml. Which approach correctly delivers this file into the Pod?

A developer wants to store the entire contents of a 3 MB application configuration file inside a single ConfigMap and mount it into their Pods. When they try to create the ConfigMap, the API server rejects it. What is the most likely reason for the rejection?

A developer stores an application's configuration in a ConfigMap and mounts it into a Pod as environment variables using the envFrom field. After updating a value in the ConfigMap with kubectl edit, they notice the running Pod still uses the old configuration value. What is the most likely reason?

A platform engineer is building a new Kubernetes cluster and wants to run containers using containerd instead of a different runtime. They need to understand how the kubelet on each node actually launches and manages containers. Through which standardized interface does the kubelet communicate with the container runtime?

A platform engineer deletes one Pod that was created by a Deployment. Almost immediately, a new Pod appears to replace it. Which control plane component is responsible for continuously comparing the actual cluster state to the desired state and driving the creation of that replacement Pod?

Your operations team needs to deploy a log-collection agent that must run exactly one instance on every worker node in the cluster, including any nodes added later through autoscaling. Which Kubernetes workload resource is designed to satisfy this requirement automatically?

A developer runs `kubectl get pods` and sees only 3 Pods, but a colleague insists the cluster is running dozens of Pods across several teams' applications. What is the most likely reason the developer sees only 3 Pods?

You run a web application as a Deployment with 3 replicas spread across a 3-node cluster. One worker node suddenly goes offline due to a hardware failure. After a few minutes, you notice the application is still serving traffic normally at full capacity. Which Kubernetes behavior best explains why the desired number of Pods was restored?

A developer needs to inject non-sensitive configuration values (such as LOG_LEVEL and CACHE_SIZE) into a container as environment variables. The values are already stored in a ConfigMap named 'app-config'. Which field in the Pod's container spec should be used to pull a specific key from that ConfigMap into a single environment variable?

You maintain a Deployment running 6 replicas of a stateless web API. During your next release, the business requires that the application never drops below full capacity and that new Pods must be verified healthy before old Pods are removed. Which change to the Deployment's update strategy best satisfies this requirement?

You created a Deployment named 'web' with 3 replicas. A teammate runs 'kubectl delete pod web-6f8d9c-abc12' to troubleshoot a hung Pod. Moments later, a new Pod with a similar name appears and the total count returns to 3. Which Kubernetes component is directly responsible for recreating the deleted Pod to maintain the desired count?

A developer is writing a Deployment manifest. They set spec.selector.matchLabels to {app: web, tier: frontend}, but under spec.template.metadata.labels they only put {app: web}. When they run kubectl apply, the command is rejected. What is the reason for this error?

A developer writes a manifest file to create a Deployment and runs 'kubectl apply -f deploy.yaml'. The command returns the error: 'error: resource mapping not found ... no matches for kind "Deployment" in version "v1"'. The file begins with 'apiVersion: v1' and 'kind: Deployment'. What change should the developer make to fix this manifest?

Your team is designing a disaster recovery plan for a self-managed Kubernetes cluster. During a review, a colleague asks which control plane component stores all cluster state and configuration data (such as the desired number of replicas, Secrets, and object definitions) that must be backed up to fully restore the cluster. Which component should you identify?

A developer is deploying a database that needs each Pod to be individually addressable by a stable DNS name, rather than being load-balanced behind a single virtual IP. They ask how to configure the Service so that DNS returns the individual Pod IPs directly instead of a single ClusterIP. What should they do?

A data team needs to run a one-time database migration script inside the cluster. The script should run in a container, execute until it finishes successfully, and then stop without being restarted or kept running. Which Kubernetes resource is designed for this workload?

A platform engineer is explaining Kubernetes control plane data flow to a new teammate. The teammate asks how the controller-manager and scheduler obtain the cluster state they need to make decisions. Which statement correctly describes how these components access cluster state?

A developer notices that Pods on one worker node cannot reach a ClusterIP Service, while Pods on all other nodes connect to it fine. All Pod endpoints are healthy and the Service selector is correct. Investigating the node, you find that the component responsible for programming the node's iptables/IPVS rules that implement Service virtual IPs is not running. Which node component has failed?