EX280 Practice Test 23 — 15 Questions

Question 1

Which THREE actions are required when manually setting up a pre-provisioned PersistentVolume backed by an existing storage asset?

Accepted Answer

Specify spec.accessModes to match expected claim requirements.. When manually creating a pre-provisioned PersistentVolume, you must define the storage capacity in spec.capacity.storage (option D) so the PV advertises the correct size that a PVC can request and bind to. You must also set spec.accessModes (option B) such as ReadWriteOnce, ReadOnlyMany, or ReadWriteMany so the PV's supported modes match the PVC's requested access mode for binding. Finally, you must provide the volume source configuration (option C), e.g., csi with driver/volumeHandle or nfs with server/path, because this tells Kubernetes which existing storage asset to attach and how to mount it. Option A is wrong because allowVolumeExpansion is a StorageClass field, not a per-namespace setting, and it is irrelevant to a manually created PV. Option E is wrong because VolumeSnapshotClass is only needed for snapshot operations, not for defining a pre-provisioned PV.

Answer

Set allowVolumeExpansion to false on all namespaces.

Answer

Create a matching VolumeSnapshotClass before defining the PV.

Question 2

An administrator needs to collect cluster-wide diagnostic information from an OpenShift 4.14 cluster for a Red Hat support case. Which command should be executed?

Accepted Answer

oc adm must-gather. `oc adm must-gather` is the official OpenShift command that collects cluster-wide diagnostic data — including clusteroperator status, pod logs, events, and resource definitions — into a tarball suitable for Red Hat support. It is the standard first step for any support case and is documented as such in the OpenShift support workflow.

Answer

oc adm diagnose

Answer

oc cluster-info dump

Answer

oc get clusteroperators -o yaml

Question 3

A developer deploys a pod with an emptyDir volume. The application running inside writes temporary files. What happens to these files when the container crashes and restarts within the same pod?

Accepted Answer

The files are preserved because emptyDir lifetime is tied to the pod, not individual containers.. An emptyDir volume in Kubernetes is created when a pod is assigned to a node and exists for the lifetime of that pod. If a container within the pod crashes and restarts, the emptyDir volume and its data persist because the pod itself has not been deleted. The files are preserved as long as the pod remains on the node.

Answer

The files are backed up to the cluster control plane automatically.

Answer

The files are deleted immediately because the container filesystem is ephemeral.

Answer

The volume is unmounted and reattached via the CSI driver.

Question 4

An OpenShift cluster's SDN (OVN-Kubernetes) experiences packet loss between nodes. The administrator needs to inspect the Open vSwitch (OVS) flow tables on a specific worker node. How should they access the node to run 'ovs-ofctl dump-flows'?

Accepted Answer

oc debug node/ -- chroot /host ovs-ofctl dump-flows br-int. To inspect OVS flow tables on a specific node, the administrator must run 'ovs-ofctl' inside the node's host network namespace. 'oc debug node/ -- chroot /host ' starts a debug pod on the node, chroots into the host filesystem, and runs the command with access to the host's OVS binaries and sockets — which is exactly what 'ovs-ofctl dump-flows br-int' requires.

Answer

oc adm diagnostics ovs

Answer

oc exec daemonset/ovn-controller -- ovs-ofctl dump-flows

Answer

oc rsh daemonset/ovnkube-node

Question 5

Which component in OpenShift 4.14 is responsible for orchestrating the upgrade of the entire cluster from one minor version to another?

Accepted Answer

Cluster Version Operator (CVO). The Cluster Version Operator (CVO) is the OpenShift component responsible for orchestrating cluster upgrades. It watches the ClusterVersion custom resource, fetches the desired release payload from the release image, and coordinates the upgrade of all cluster operators in the correct order. The CVO ensures that each operator reaches its target version before proceeding, providing a controlled, verifiable upgrade path.

Answer

Machine Config Operator (MCO)

Answer

Cluster Infrastructure Operator (CIO)

Answer

Operator Lifecycle Manager (OLM)

Question 6

What is the primary difference between a Deployment and a DeploymentConfig in OpenShift?

Accepted Answer

DeploymentConfigs are OpenShift-specific. DeploymentConfigs are a legacy OpenShift-specific resource that predates native Kubernetes Deployments. They are not part of upstream Kubernetes and are only available in OpenShift, whereas Deployments are a standard Kubernetes API resource. This is the primary architectural difference: DeploymentConfigs rely on OpenShift's ImageStreams and custom rollout logic, while Deployments use ReplicaSets and the standard Kubernetes deployment controller.

Answer

Deployments support triggers, DeploymentConfigs do not

Answer

Deployments can be scaled, DeploymentConfigs cannot

Answer

DeploymentConfigs do not support rollbacks

Question 7

You need to update an application without downtime. Which deployment strategy is most appropriate?

Accepted Answer

Rolling. Rolling deployment is the most appropriate strategy for updating an application without downtime because it incrementally replaces old pods with new ones, ensuring that a portion of the application remains available throughout the update. This is the default deployment strategy in OpenShift (and Kubernetes), and it maintains service continuity by scaling down the old ReplicaSet while scaling up the new one, with configurable parameters like maxUnavailable and maxSurge to control the pace. Unlike other strategies, rolling updates do not require additional infrastructure or complex traffic routing, making it the standard choice for zero-downtime updates in OpenShift.

Answer

Canary

Answer

Blue-Green

Answer

Recreate

Question 8

A developer deploys an application that mounts a PVC in read-only mode inside the pod specification. How is this configured in the Pod's volumeMounts?

Accepted Answer

Set readOnly: true in the container's volumeMounts entry.. Read-only mounting of a PVC inside a pod is set per-container via `readOnly: true` in the volumeMounts entry. This tells the kubelet to mount the volume read-only for that container, regardless of the PVC's access modes.

Answer

Set accessModes to ReadOnlyMany on the PVC object.

Answer

Set volumeMode: ReadOnly in the PVC spec.

Answer

Annotate the PVC with 'volume.beta.kubernetes.io/readonly'.

Question 9

An administrator wants to view the logs of a specific container named 'backend' inside a pod with multiple containers. Which command should be used?

Accepted Answer

oc logs pod/my-pod -c backend. `oc logs pod/my-pod -c backend` uses the `-c` flag to specify the container name 'backend' within a multi-container pod, which is the correct syntax to retrieve that container's logs. Without `-c`, oc logs would default to the first container or error out, so the flag is required.

Answer

oc logs pod/my-pod backend

Answer

oc rsh pod/my-pod backend

Answer

oc describe pod/my-pod -c backend

Question 10

An administrator needs to roll back a Deployment in OpenShift to a specific previous revision because the latest update introduced a critical database connection bug. Which command identifies the available revisions and their associated change causes before executing the rollback?

Accepted Answer

oc rollout history deployment/. The `oc rollout history deployment/` command is specifically designed to display the revision history of a Deployment, including the revision number and the change cause (the reason for each rollout). This allows the administrator to identify which revision to roll back to before executing `oc rollout undo deployment/ --to-revision=`. It directly addresses the need to see available revisions and their associated change causes.

Answer

oc get replicasets --selector=app=my-app

Answer

oc get deployment/<deployment-name> -o yaml

Answer

oc describe deploymentconfig <deployment-config-name>

Question 11

An administrator is investigating why cluster operator upgrades are failing. Which TWO locations or commands provide detailed diagnostic information about cluster operators? (Choose TWO)

Accepted Answer

Run 'oc describe clusteroperator ' to inspect status conditions and messages.. Option A is correct because 'oc describe clusteroperator ' surfaces the ClusterOperator object's status.conditions, including Available, Progressing, Degraded, and their human-readable messages, which directly reveal why an upgrade is stuck or failing. Option C is correct because the actual controller pods (for example, the cluster-version-operator pod in openshift-cluster-version or an operator's own controller pods in its namespace) emit detailed logs that explain reconciliation errors, failed image pulls, or API conflicts behind the conditions. Option B is wrong because the DNS configuration map in the default namespace only holds cluster DNS settings and has nothing to do with operator upgrade diagnostics. Option D is wrong because 'oc adm cluster-operator-reset --all' is not a valid diagnostic command and would not report operator status. Option E is wrong because MachineConfigPool status conditions report node configuration rollout state, not OLM or cluster operator errors.

Answer

Check the global DNS configuration map in the default namespace.

Answer

Run 'oc adm cluster-operator-reset --all'.

Answer

Inspect the MachineConfigPool status conditions for OLM errors.

Question 12

An administrator needs to completely remove a Helm release named my-redis from the cluster, including its history. Which Helm command should be executed?

Accepted Answer

helm uninstall my-redis. The correct command to completely remove a Helm release and its history is helm uninstall my-redis. In Helm 3, uninstall replaces the delete command and removes the release and its history by default.

Answer

helm remove my-redis

Answer

helm delete my-redis --purge

Answer

helm drop my-redis

Question 13

A cluster administrator wants to grant a group of users read access to all Pod logs across every namespace in the cluster. Which ClusterRole and binding approach should be used?

Accepted Answer

ClusterRole with apiGroups: [''], resources: ['pods/log'], verbs: ['get'] bound via ClusterRoleBinding. To grant read access to pod logs across all namespaces, you need a ClusterRole that grants 'get' on the 'pods/log' subresource in the core API group, bound with a ClusterRoleBinding to the target group. The ClusterRoleBinding ensures the permission applies cluster-wide rather than in a single namespace. This is the canonical RBAC pattern for cross-namespace log access.

Answer

RoleBinding in each individual namespace pointing to the 'view' ClusterRole

Answer

SecurityContextConstraints modification

Answer

ClusterRole with apiGroups: ['apps'], resources: ['deployments/scale'], verbs: ['get']

Question 14

A developer has deployed a Helm chart in OpenShift and needs to list all currently installed Helm releases in the current namespace. Which command should be used?

Accepted Answer

helm list. The helm list command lists all Helm releases in the current namespace (or all namespaces with -A). It shows release name, namespace, revision, status, chart, and app version. This is the standard command to view installed releases.

Answer

helm get releases

Answer

helm status

Answer

helm search installed

Question 15

What is the effect of setting 'allowVolumeExpansion: true' in a StorageClass?

Accepted Answer

It permits users to increase the storage size of PVCs created from this StorageClass.. Setting allowVolumeExpansion: true in a StorageClass allows users to increase the size of PVCs created from that StorageClass. This enables online expansion of volumes, provided the underlying storage provider supports it.

Answer

It automatically shrinks PVCs when storage usage drops below 50%.

Answer

It allows multiple pods to write to an RWO volume simultaneously.

Answer

It allows the cluster to automatically scale the number of worker nodes based on storage demand.