CKA Workloads & Scheduling — All Questions With Answers

Question 1

A DevOps team wants to ensure that a critical web application pod runs on a dedicated set of nodes with SSDs. Which Kubernetes feature should they use to achieve this?

Accepted Answer

Node affinity. Node affinity is a Kubernetes feature that allows you to constrain which nodes a pod can be scheduled on based on node labels. By labeling nodes with SSDs (e.g., `disk-type=ssd`) and defining a `requiredDuringSchedulingIgnoredDuringExecution` node affinity rule in the pod spec, the scheduler will only place the pod on nodes matching that label, ensuring it runs on the dedicated set of nodes.

Answer

Pod priority and preemption

Answer

Taints and tolerations

Answer

Resource quotas

Question 2

A Kubernetes cluster has a deployment with 3 replicas. After a node failure, you notice that only 2 pods are running, and the deployment has not rescheduled the missing pod. What is the most likely cause?

Accepted Answer

The node controller has not yet evicted the pod. When a node fails, the node controller marks the node as `NodeReady=False` and waits for a configurable timeout (`pod-eviction-timeout`, default 5 minutes) before evicting pods. Until eviction, the deployment's ReplicaSet sees the pod as still existing (though on an unreachable node) and does not create a replacement. Option C correctly identifies that the node controller has not yet evicted the pod, which is the default behavior.

Answer

The deployment has a resource quota that prevents new pods

Answer

The pod's terminationGracePeriodSeconds is set to 0

Answer

The deployment's replicas field is set to 2

Question 3

You have a StatefulSet with 5 pods, each requiring a unique stable network identity. The StatefulSet is scaled down from 5 to 3. Which pods will be terminated?

Accepted Answer

Pods with the highest ordinals (4 and 3). When a StatefulSet is scaled down, Kubernetes terminates pods in reverse order of their ordinal indices, starting from the highest. For a StatefulSet with 5 pods (ordinals 0-4) scaled to 3, pods with ordinals 4 and 3 are terminated first, ensuring that the remaining pods (0, 1, 2) maintain their stable network identities and storage.

Answer

Random pods

Answer

Pods with the lowest ordinals (0 and 1)

Answer

Pods with the highest resource usage

Question 4

An application requires that a pod runs on a node that has a GPU. The cluster has nodes with and without GPUs labeled as 'gpu=true' and 'gpu=false'. Which scheduling method should be used?

Accepted Answer

nodeSelector with gpu=true. Option D is correct because `nodeSelector` is the simplest and most direct way to force a pod to run only on nodes that have a specific label, such as `gpu=true`. This ensures the pod is scheduled exclusively on GPU-equipped nodes without requiring taints, tolerations, or complex affinity rules. The `nodeSelector` field in the pod spec matches against node labels at scheduling time, making it ideal for this straightforward requirement.

Answer

Taint on non-GPU nodes and toleration on the pod

Answer

Pod affinity to prefer GPU nodes

Answer

Node affinity with a requiredDuringSchedulingIgnoredDuringExecution rule for gpu=true

Question 5

A cluster administrator wants to ensure that no pods are scheduled on the master node(s). Which approach is the best practice?

Accepted Answer

Add a taint to the master node. Adding a taint to the master node(s) with the `node-role.kubernetes.io/master:NoSchedule` effect is the best practice because it prevents the Kubernetes scheduler from placing any pods on that node unless a pod explicitly tolerates the taint. This ensures that only critical system pods (which include the toleration) can run on the master, keeping it dedicated to cluster control plane operations.

Answer

Delete the master node from the cluster

Answer

Use a resource quota on the master namespace

Answer

Set nodeSelector on the master node

Question 6

A pod is stuck in 'Pending' state. The 'kubectl describe pod' output shows the event: '0/4 nodes are available: 3 node(s) had taint {node.kubernetes.io/unreachable: }, and 1 node(s) had taint {node.kubernetes.io/not-ready: }.' What is the most likely reason?

Accepted Answer

The pod does not have tolerations for the node taints. The pod is stuck in 'Pending' because none of the available nodes can schedule it. The events explicitly show taints: 'node.kubernetes.io/unreachable' on 3 nodes and 'node.kubernetes.io/not-ready' on 1 node. By default, pods do not tolerate these taints, so the scheduler cannot place the pod unless it has matching tolerations. Option B correctly identifies that the pod lacks the required tolerations.

Answer

The pod has resource requests that exceed available capacity

Answer

The nodes are cordoned

Answer

The kube-scheduler is not running

Question 7

You have a Deployment that runs a batch job. The job should run on a node that has a specific custom resource (e.g., a license dongle). Which approach should you use?

Accepted Answer

Use node affinity with a requiredDuringSchedulingIgnoredDuringExecution rule. Node affinity with a `requiredDuringSchedulingIgnoredDuringExecution` rule is the correct approach because it allows you to schedule the pod exclusively on nodes that have a specific custom resource (e.g., a license dongle) by matching node labels. This rule is a hard constraint that must be satisfied during scheduling, ensuring the pod only runs on nodes with the required resource. Unlike `nodeSelector`, node affinity supports more expressive matching (e.g., `In`, `NotIn`, `Exists`) and can be combined with other scheduling constraints.

Answer

Define a nodeSelector in the pod spec

Answer

Assign the pod a high priority so it gets scheduled on any node

Answer

Use pod anti-affinity to avoid nodes without the resource

Question 8

A developer wants to deploy a pod that will run only once to initialize a database schema. Which Kubernetes resource should they use?

Accepted Answer

Job. A Job is the correct Kubernetes resource for a one-time task that runs to completion, such as initializing a database schema. Unlike controllers that maintain a desired number of replicas, a Job creates one or more Pods and ensures they successfully terminate, making it ideal for batch or initialization workloads.

Answer

DaemonSet

Answer

Deployment

Answer

CronJob

Question 9

Which TWO of the following are valid methods to ensure a pod is scheduled on a node that is part of a specific availability zone? (Assume nodes are labeled with 'failure-domain.beta.kubernetes.io/zone').

Accepted Answer

Use nodeSelector with the zone label. Option A is correct because `nodeSelector` is a simple, declarative way to constrain a pod to nodes with specific labels. By setting `nodeSelector` with `failure-domain.beta.kubernetes.io/zone: <zone>`, the scheduler will only consider nodes that have that exact label key-value pair, ensuring the pod lands in the desired availability zone.

Answer

Use a toleration for a taint that exists only on nodes in the zone

Answer

Use pod affinity to attract pods to nodes in that zone

Answer

Set spec.nodeName to the name of a node in the zone

Question 10

Which THREE of the following are characteristics of DaemonSets?

Accepted Answer

A DaemonSet runs exactly one pod per node. A DaemonSet ensures that exactly one pod runs on each node in the cluster (or a subset of nodes if node selectors are used). When a new node is added, the DaemonSet automatically schedules a pod on it; when a node is removed, the pod is garbage collected. This is enforced by the DaemonSet controller, which does not use a replica count like a Deployment or StatefulSet.

Answer

DaemonSets can be scaled down by reducing the number of replicas

Answer

A DaemonSet can be used to run a batch job that completes

Question 11

Which TWO of the following are valid reasons to use a StatefulSet instead of a Deployment?

Accepted Answer

The application requires unique network identities (e.g., hostnames). Option B is correct because StatefulSets assign each pod a unique, stable network identity (e.g., a hostname like 'web-0', 'web-1') derived from the StatefulSet's name and an ordinal index. This is essential for applications like databases (e.g., Cassandra, ZooKeeper) that rely on consistent hostnames for cluster membership and discovery. Deployments, in contrast, generate random pod names and do not guarantee stable network identities.

Answer

The application is a batch job that should run to completion

Answer

The application needs to run on all nodes in the cluster

Answer

The application is stateless and can be scaled arbitrarily

Question 12

You are managing a Kubernetes cluster that hosts a microservices application. One of the services, 'payment-processor', is critical and must always be available. It has a Deployment with 3 replicas, each requesting 1 CPU and 2Gi memory. Recently, the team added a new service 'data-analyzer' that runs as a DaemonSet on all nodes, consuming significant CPU and memory. After the addition, you notice that 'payment-processor' pods are occasionally being evicted, and new pods are slow to be scheduled. You check node resource usage and find that some nodes are overcommitted. You want to ensure that 'payment-processor' pods are never evicted and are scheduled before less critical workloads. Which action should you take?

Accepted Answer

Create a PriorityClass with a high value and assign it to the 'payment-processor' Deployment. PriorityClass with a high value ensures that 'payment-processor' pods are considered higher priority than other pods during scheduling and eviction. When nodes are overcommitted, the Kubernetes scheduler will preempt lower-priority pods to make room for higher-priority pods, and the kubelet will evict lower-priority pods first when resources are scarce. This directly addresses the requirement that 'payment-processor' pods are never evicted and are scheduled before less critical workloads.

Answer

Add a taint to nodes that have low resources and add tolerations only to 'payment-processor' pods

Answer

Increase the resource requests for 'payment-processor' pods to guarantee resources

Answer

Use node affinity to ensure 'payment-processor' pods run on dedicated nodes

Question 13

Your team is deploying a new application that consists of a web frontend and a backend API. The frontend must be accessible from outside the cluster, and the backend should only be accessible from within the cluster. The cluster has multiple namespaces: 'frontend' and 'backend'. You have been asked to design the deployment. The frontend Deployment should have 5 replicas, and the backend Deployment should have 3 replicas. Additionally, you need to ensure that the frontend pods can communicate with the backend pods using a stable DNS name. You also want to isolate the backend from other namespaces. Which set of resources should you create?

Accepted Answer

Frontend: Deployment, Service (LoadBalancer); Backend: Deployment, Service (ClusterIP); NetworkPolicy to allow ingress from frontend namespace and deny others. Option D is correct because it uses a LoadBalancer Service for the frontend to provide external access, a ClusterIP Service for the backend to restrict access to within the cluster, and a NetworkPolicy that allows ingress traffic from the frontend namespace to the backend while denying all other ingress, thus isolating the backend. This ensures the frontend pods can reach the backend via a stable DNS name (the ClusterIP Service's DNS name) and meets the requirement of backend isolation from other namespaces.

Answer

Frontend: Deployment, Service (NodePort); Backend: Deployment, Service (ClusterIP); no NetworkPolicy

Answer

Frontend: Deployment, Service (ClusterIP); Backend: Deployment, Service (ClusterIP); NetworkPolicy to allow ingress from frontend namespace

Answer

Frontend: Deployment, Service (LoadBalancer); Backend: Deployment, Service (LoadBalancer); NetworkPolicy to allow only frontend to backend

Question 14

A developer deployed a Pod that is stuck in Pending state. The cluster has one worker node with taint 'node.kubernetes.io/disk-pressure:NoSchedule'. The Pod does not specify any tolerations. What is the most likely cause?

Accepted Answer

The node has a taint that the Pod does not tolerate.. A Pod stuck in Pending state indicates the scheduler cannot find a suitable node. The cluster has a worker node with the taint 'node.kubernetes.io/disk-pressure:NoSchedule', and the Pod has no tolerations. Since taints with effect NoSchedule prevent scheduling of Pods that do not tolerate them, the Pod cannot be placed on that node, leaving it in Pending.

Answer

The Pod was evicted due to resource pressure.

Answer

The Pod requests more CPU than available on the node.

Answer

The scheduler failed to communicate with the API server.

Question 15

An administrator wants to ensure that a critical Pod always runs on a node that has an SSD. Which approach should be used?

Accepted Answer

Label SSD nodes with 'disk=ssd' and use nodeSelector in the Pod spec.. Option D is correct because using a nodeSelector with a label like 'disk=ssd' ensures that the Pod is scheduled only on nodes that have that specific label, which directly matches the requirement to run the Pod on a node with an SSD. This is the simplest and most reliable method for node-level selection in Kubernetes, as it leverages the scheduler's built-in filtering mechanism.

Answer

Use podAffinity to prefer nodes running other Pods.

Answer

Set spec.nodeName to an SSD node's name.

Answer

Add a taint to nodes without SSD and add a toleration to the Pod.

Question 16

A team observes that a Deployment's Pods are being scheduled on nodes with different architectures (amd64 and arm64). The Deployment does not specify nodeSelector or affinity. The cluster has a mix of node pools. What is the best practice to ensure Pods only run on amd64 nodes?

Accepted Answer

Add a label 'kubernetes.io/arch: amd64' to all amd64 nodes and use nodeSelector.. Option B is correct because the recommended way to constrain Pods to nodes with a specific architecture is to label those nodes (e.g., with `kubernetes.io/arch: amd64`) and then use `nodeSelector` in the Pod spec. This ensures the scheduler only places Pods on nodes matching the label, which is a simple, declarative, and Kubernetes-native approach. The Deployment does not specify any scheduling constraints, so adding `nodeSelector` is the best practice to enforce architecture-specific placement.

Answer

Add a toleration for 'arch=amd64:NoSchedule' to the Pod.

Answer

Use podAntiAffinity to avoid scheduling on arm64 nodes.

Answer

Set a runtimeClassName for amd64 in the Pod spec.

Question 17

A Pod with a restartPolicy of 'OnFailure' exits with code 0. What will happen?

Accepted Answer

The container will not restart, and the Pod will be in Succeeded phase.. When a Pod has a restartPolicy of 'OnFailure' and its container exits with code 0 (indicating successful completion), the container will not be restarted. Instead, the Pod transitions to the Succeeded phase, as defined by Kubernetes Pod lifecycle semantics. This is because 'OnFailure' only triggers a restart on a non-zero exit code, which signifies a failure.

Answer

The container will restart immediately.

Answer

The Pod will be terminated.

Answer

The Pod will remain in Running state.

Question 18

A company runs a batch job that processes a queue. The job should run to completion exactly once. Which resource should be used?

Accepted Answer

Job. A Kubernetes Job is designed to run a specified number of pods to successful completion. When the pod exits with a zero exit code, the Job is marked as complete and will not be restarted, making it the correct choice for a batch job that must run exactly once.

Answer

DaemonSet

Answer

CronJob

Answer

Deployment

Question 19

A Kubernetes cluster has a node pool with GPU nodes labeled 'accelerator=nvidia-tesla'. A Pod requires a GPU. Which configuration is necessary?

Accepted Answer

Set nodeSelector to 'accelerator=nvidia-tesla' and request 'nvidia.com/gpu' in resources.. Option C is correct because a Pod that requires a GPU must both be scheduled onto a node with the appropriate GPU label and explicitly request the GPU resource. The `nodeSelector` ensures the Pod lands on a node labeled `accelerator=nvidia-tesla`, and requesting `nvidia.com/gpu` in `resources.requests` or `resources.limits` (typically limits) tells the kubelet to allocate a GPU device to the container. Without the resource request, the scheduler has no way to account for GPU capacity, and without the nodeSelector, the Pod might be scheduled on a non-GPU node.

Answer

Use nodeAffinity with requiredDuringSchedulingIgnoredDuringExecution for the GPU label.

Answer

Set resources.limits for 'nvidia.com/gpu' only.

Answer

Add a toleration for GPU node taints.

Question 20

A Deployment has replicas=3 and uses RollingUpdate with maxSurge=1 and maxUnavailable=1. During an update, one new Pod is created, and one old Pod is terminated. What is the total number of Pods during the update?

Accepted Answer

Between 2 and 4. During a RollingUpdate, the total number of Pods can vary between the desired replicas (3) and the desired replicas plus maxSurge (1), i.e., up to 4. With maxUnavailable=1, at least 2 Pods must be available. The update creates one new Pod before terminating one old Pod, so the total Pod count can be 3 (if the old Pod is terminated before the new one is ready) or 4 (if the new Pod is created before the old one is terminated). Thus, the range is between 2 and 4.

Answer

Between 2 and 3

Answer

Exactly 4

Answer

Always 3

CKA Workloads & Scheduling — All Questions With Answers

A DevOps team wants to ensure that a critical web application pod runs on a dedicated set of nodes with SSDs. Which Kubernetes feature should they use to achieve this?

A Kubernetes cluster has a deployment with 3 replicas. After a node failure, you notice that only 2 pods are running, and the deployment has not rescheduled the missing pod. What is the most likely cause?

You have a StatefulSet with 5 pods, each requiring a unique stable network identity. The StatefulSet is scaled down from 5 to 3. Which pods will be terminated?

An application requires that a pod runs on a node that has a GPU. The cluster has nodes with and without GPUs labeled as 'gpu=true' and 'gpu=false'. Which scheduling method should be used?

A cluster administrator wants to ensure that no pods are scheduled on the master node(s). Which approach is the best practice?

A pod is stuck in 'Pending' state. The 'kubectl describe pod' output shows the event: '0/4 nodes are available: 3 node(s) had taint {node.kubernetes.io/unreachable: }, and 1 node(s) had taint {node.kubernetes.io/not-ready: }.' What is the most likely reason?

You have a Deployment that runs a batch job. The job should run on a node that has a specific custom resource (e.g., a license dongle). Which approach should you use?

A developer wants to deploy a pod that will run only once to initialize a database schema. Which Kubernetes resource should they use?

Which TWO of the following are valid methods to ensure a pod is scheduled on a node that is part of a specific availability zone? (Assume nodes are labeled with 'failure-domain.beta.kubernetes.io/zone').

Which THREE of the following are characteristics of DaemonSets?

Which TWO of the following are valid reasons to use a StatefulSet instead of a Deployment?

A developer deployed a Pod that is stuck in Pending state. The cluster has one worker node with taint 'node.kubernetes.io/disk-pressure:NoSchedule'. The Pod does not specify any tolerations. What is the most likely cause?

An administrator wants to ensure that a critical Pod always runs on a node that has an SSD. Which approach should be used?

A team observes that a Deployment's Pods are being scheduled on nodes with different architectures (amd64 and arm64). The Deployment does not specify nodeSelector or affinity. The cluster has a mix of node pools. What is the best practice to ensure Pods only run on amd64 nodes?

A Pod with a restartPolicy of 'OnFailure' exits with code 0. What will happen?

A company runs a batch job that processes a queue. The job should run to completion exactly once. Which resource should be used?

A Kubernetes cluster has a node pool with GPU nodes labeled 'accelerator=nvidia-tesla'. A Pod requires a GPU. Which configuration is necessary?

A Deployment has replicas=3 and uses RollingUpdate with maxSurge=1 and maxUnavailable=1. During an update, one new Pod is created, and one old Pod is terminated. What is the total number of Pods during the update?

Which TWO of the following are valid ways to restrict a Pod to run only on nodes with a specific label? (Select 2)

Which THREE of the following are valid considerations when using resource requests and limits? (Select 3)

A DevOps team wants to ensure that a critical application Pod is always scheduled on a node that has SSD storage. They have labeled one node with 'disk=ssd'. Which scheduling approach should they use to guarantee this placement?

A Pod is in Pending state for a long time. 'kubectl describe pod' shows the event: '0/3 nodes are available: 3 node(s) had taints that the pod didn't tolerate'. What is the most likely issue?

A cluster administrator wants to ensure that a set of batch processing Pods are preemptible and should not cause disruption to other critical workloads. Which combination of scheduling features should be used?

A Pod in a Deployment is CrashLoopBackOff. 'kubectl logs' shows the application exits with code 1 after printing one line. The Pod has a liveness probe that checks an HTTP endpoint. What should be checked first?

Which TWO of the following are valid ways to ensure that a Pod runs on a node that has a GPU? (Choose TWO.)

Which THREE of the following are valid reasons for a Pod to be in Pending state? (Choose THREE.)

Which TWO of the following statements about Kubernetes DaemonSets are correct?

Which TWO statements about Kubernetes pod lifecycle and scheduling are correct? (Select two.)

Drag and drop the steps to troubleshoot a CrashLoopBackOff pod into the correct order.

Drag and drop the steps to troubleshoot a Node that is in NotReady state into the correct order.

Match each kubectl command to its purpose.

Match each troubleshooting scenario to its likely cause.

CKA Workloads & Scheduling — All Questions With Answers

A DevOps team wants to ensure that a critical web application pod runs on a dedicated set of nodes with SSDs. Which Kubernetes feature should they use to achieve this?

A Kubernetes cluster has a deployment with 3 replicas. After a node failure, you notice that only 2 pods are running, and the deployment has not rescheduled the missing pod. What is the most likely cause?

You have a StatefulSet with 5 pods, each requiring a unique stable network identity. The StatefulSet is scaled down from 5 to 3. Which pods will be terminated?

An application requires that a pod runs on a node that has a GPU. The cluster has nodes with and without GPUs labeled as 'gpu=true' and 'gpu=false'. Which scheduling method should be used?

A cluster administrator wants to ensure that no pods are scheduled on the master node(s). Which approach is the best practice?

A pod is stuck in 'Pending' state. The 'kubectl describe pod' output shows the event: '0/4 nodes are available: 3 node(s) had taint {node.kubernetes.io/unreachable: }, and 1 node(s) had taint {node.kubernetes.io/not-ready: }.' What is the most likely reason?

You have a Deployment that runs a batch job. The job should run on a node that has a specific custom resource (e.g., a license dongle). Which approach should you use?

A developer wants to deploy a pod that will run only once to initialize a database schema. Which Kubernetes resource should they use?

Which TWO of the following are valid methods to ensure a pod is scheduled on a node that is part of a specific availability zone? (Assume nodes are labeled with 'failure-domain.beta.kubernetes.io/zone').

Which THREE of the following are characteristics of DaemonSets?

Which TWO of the following are valid reasons to use a StatefulSet instead of a Deployment?

A developer deployed a Pod that is stuck in Pending state. The cluster has one worker node with taint 'node.kubernetes.io/disk-pressure:NoSchedule'. The Pod does not specify any tolerations. What is the most likely cause?

An administrator wants to ensure that a critical Pod always runs on a node that has an SSD. Which approach should be used?

A team observes that a Deployment's Pods are being scheduled on nodes with different architectures (amd64 and arm64). The Deployment does not specify nodeSelector or affinity. The cluster has a mix of node pools. What is the best practice to ensure Pods only run on amd64 nodes?

A Pod with a restartPolicy of 'OnFailure' exits with code 0. What will happen?

A company runs a batch job that processes a queue. The job should run to completion exactly once. Which resource should be used?

A Kubernetes cluster has a node pool with GPU nodes labeled 'accelerator=nvidia-tesla'. A Pod requires a GPU. Which configuration is necessary?

A Deployment has replicas=3 and uses RollingUpdate with maxSurge=1 and maxUnavailable=1. During an update, one new Pod is created, and one old Pod is terminated. What is the total number of Pods during the update?

Which TWO of the following are valid ways to restrict a Pod to run only on nodes with a specific label? (Select 2)

Which THREE of the following are valid considerations when using resource requests and limits? (Select 3)

A DevOps team wants to ensure that a critical application Pod is always scheduled on a node that has SSD storage. They have labeled one node with 'disk=ssd'. Which scheduling approach should they use to guarantee this placement?

A Pod is in Pending state for a long time. 'kubectl describe pod' shows the event: '0/3 nodes are available: 3 node(s) had taints that the pod didn't tolerate'. What is the most likely issue?

A cluster administrator wants to ensure that a set of batch processing Pods are preemptible and should not cause disruption to other critical workloads. Which combination of scheduling features should be used?

A Pod in a Deployment is CrashLoopBackOff. 'kubectl logs' shows the application exits with code 1 after printing one line. The Pod has a liveness probe that checks an HTTP endpoint. What should be checked first?

Which TWO of the following are valid ways to ensure that a Pod runs on a node that has a GPU? (Choose TWO.)

Which THREE of the following are valid reasons for a Pod to be in Pending state? (Choose THREE.)

Which TWO of the following statements about Kubernetes DaemonSets are correct?

Which TWO statements about Kubernetes pod lifecycle and scheduling are correct? (Select two.)

Drag and drop the steps to troubleshoot a CrashLoopBackOff pod into the correct order.

Drag and drop the steps to troubleshoot a Node that is in NotReady state into the correct order.

Match each kubectl command to its purpose.

Match each troubleshooting scenario to its likely cause.