EX280 Cluster Installation And Management — 20 Questions

Question 1

An administrator needs to modify the SSH key used for debugging worker nodes across an OpenShift 4.14 cluster. Which resource type should the administrator edit or create to apply this change cluster-wide to all worker nodes?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Create or modify a MachineConfig object that targets the worker role and specifies the sshKey field.. MachineConfig objects allow administrators to manage node-level configuration changes, including injecting authorized SSH keys for the core user.

Answer

Modify the ClusterVersion custom resource spec field.

Answer

Edit the kubelet configuration map in the kube-system namespace.

Answer

Update the authentication.config.openshift.io cluster operator resource.

Question 2

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) manages the core components of OpenShift and orchestrates cluster upgrades based on the requested channel and version.

Answer

Machine Config Operator (MCO)

Answer

Cluster Infrastructure Operator (CIO)

Answer

Operator Lifecycle Manager (OLM)

Question 3

An administrator wants to apply kernel arguments to all worker nodes in an OpenShift 4.14 cluster using the Machine Config Operator. After creating a new MachineConfig object, the administrator notices that the worker nodes are not updating and the MachineConfigPool status shows 'Updating=False'. What is the most likely cause?

Accepted Answer

The MachineConfig object lacks the correct labels required to associate it with the target MachineConfigPool.. The MachineConfig object must include valid labels matching the MachineConfigPool node selector (e.g., pools.operator.machineconfiguration.openshift.io/worker: '') so the Machine Config Operator knows which pool to target.

Answer

The administrator forgot to run 'oc adm upgrade --force' to trigger node reboots.

Answer

The Cluster Version Operator must be manually restarted to detect new MachineConfig definitions.

Answer

The cluster storage provider must be re-initialized to support kernel argument persistence.

Question 4

During an upgrade of an OpenShift 4.14 cluster using the Cluster Version Operator (CVO), the upgrade status stalls at a specific component. The administrator wants to check the detailed error messages and reconciling loops of the CVO itself. Where should the administrator look?

Accepted Answer

Review the logs of the cluster-version-operator deployment in the openshift-cluster-version namespace.. The Cluster Version Operator runs in the openshift-cluster-version namespace. Its logs provide detailed reconciliation status and errors during cluster upgrades.

Answer

Inspect the clusteroperators object using 'oc describe clusteroperator base-os'.

Answer

Check the cluster-wide events in the default namespace using 'oc get events'.

Answer

Inspect the MachineConfigPool status in the openshift-machine-api namespace.

Question 5

An administrator needs to temporarily prevent the Machine Config Operator from applying pending MachineConfig changes to the worker nodes while performing troubleshooting. How should the administrator accomplish this?

Accepted Answer

Patch the worker MachineConfigPool to set 'spec.paused: true'.. To pause updates on a set of nodes, the administrator can set the 'paused: true' field on the corresponding MachineConfigPool resource.

Answer

Delete all pending MachineConfig objects from the cluster.

Answer

Scale down the machine-config-operator deployment in openshift-machine-config-operator to zero replicas.

Answer

Annotate all worker nodes with 'machineconfiguration.openshift.io/paused=true'.

Question 6

An administrator running OpenShift 4.14 wants to configure automatic approval for an Operator subscription updates using the Operator Lifecycle Manager. Which field and value in the Subscription resource must be set?

Accepted Answer

Set 'spec.installPlanApproval: Automatic'. Subscriptions have an installPlanApproval field which can be set to 'Automatic' or 'Manual'. Setting it to 'Automatic' allows OLM to automatically install updates.

Answer

Set 'spec.channel.autoApprove: yes'

Answer

Set 'spec.autoUpgrade: true'

Answer

Set 'spec.approvalStrategy: Immediate'

Question 7

An administrator needs to perform a graceful maintenance reboot on a worker node named worker-01 in an OpenShift 4.14 cluster without causing application downtime for stateless deployments. Which combination of actions should the administrator perform first?

Accepted Answer

Run 'oc adm cordon worker-01' followed by 'oc adm drain worker-01 --delete-emptydir-data --ignore-daemonsets'.. To safely maintain a worker node, the administrator must first cordon the node to prevent new pod scheduling and then drain it to gracefully evict existing workloads with proper pod disruption budgets.

Answer

Apply a MachineConfig to the worker MachineConfigPool pausing the updates, then reboot the node.

Answer

Stop the kubelet service on worker-01 via systemctl and reboot the underlying operating system.

Answer

Run 'oc delete node worker-01' directly to force the cluster control plane to automatically reschedule workloads.

Question 8

An OpenShift 4.14 cluster administrator has installed an Operator from OperatorHub into a custom namespace using a Subscription. The administrator notices that the Operator pod is not being created. Upon checking the Subscription, the installation mode is set to AllNamespaces, but the Operator target namespace is restricted. Which Operator Lifecycle Manager (OLM) object should the administrator inspect to troubleshoot why the CSV (ClusterServiceVersion) is not installing?

Accepted Answer

Inspect the OperatorGroup in the target namespace to ensure its targetNamespaces match or support the Subscription scope.. When using OLM, the OperatorGroup defines the namespace scope where Operators can be installed. If the OperatorGroup does not match the Subscription's install mode, the CSV will not install.

Answer

Check the MachineConfigPool for paused reconciliation flags.

Answer

Review the ClusterVersion resource status for pending updates.

Answer

Inspect the KubeletConfig custom resource for validation errors.

Question 9

An administrator notices that a worker node is in a 'NotReady' state due to a storage failure. The administrator successfully replaces the underlying physical machine and wants to clear the old node object from the OpenShift 4.14 cluster. Which command should be used?

Accepted Answer

oc delete node worker-old. Once a node is drained or permanently offline, the administrator can delete the node resource using 'oc delete node <node-name>'.

Answer

oc adm cordon worker-old --purge

Answer

oc patch machine worker-old --type=merge -p '{"spec":{"deleted":true}}'

Answer

oc remove node-status worker-old

Question 10

What is the primary function of the Machine Config Operator (MCO) in OpenShift 4.14?

Accepted Answer

Managing operating system configurations, file system changes, and software updates for cluster nodes.. The MCO manages and applies configuration changes to the operating system on control plane and worker nodes, such as updates to system files, certs, and kernel parameters.

Answer

Handling external DNS records and cluster ingress routing.

Answer

Provisioning cloud provider virtual machines for cluster scaling.

Answer

Managing container image registries and secure image signing.

Question 11

An administrator needs to configure custom container runtime parameters (such as the maximum pod log size or maximum number of processes per container) across all worker nodes in an OpenShift 4.14 cluster. Which custom resource should the administrator create?

Accepted Answer

ContainerRuntimeConfig. Container runtime settings such as max log size and storage options are managed using the ContainerRuntimeConfig custom resource in OpenShift.

Answer

MachineHealthCheck

Answer

KubeletConfig

Answer

NodeNetworkConfigurationPolicy

Question 12

An administrator needs to ensure that if a worker node freezes or becomes unresponsive for more than 5 minutes, the cluster automatically remediates it by deleting and recreating the underlying virtual machine instance. Which OpenShift 4.14 feature should the administrator configure?

Accepted Answer

MachineHealthCheck. MachineHealthCheck allows administrators to define criteria (such as node not ready conditions) and automatically remediate unhealthy nodes by deleting their corresponding Machine objects.

Answer

NodeAutoscaler

Answer

MachineConfigPool

Answer

ClusterAutoscaler

Question 13

Which OpenShift 4.14 operator provides a catalog of certified third-party and Red Hat operators available for cluster installation?

Accepted Answer

OperatorHub / Cluster Catalog Operator. OperatorHub is the mechanism and user interface catalog powered by the Cluster Catalog Operators where administrators discover and install operators.

Answer

Console Operator

Answer

Machine API Operator

Answer

Cluster Version Operator

Question 14

An administrator is troubleshooting a failed cluster upgrade in OpenShift 4.14. The upgrade channel is set to 'stable-4.14', but the cluster refuses to update to the latest target version. The administrator runs 'oc get clusterversion' and notes that a specific ClusterOperator reports 'Degraded=True'. What is the recommended next step?

Accepted Answer

Describe or inspect the degraded ClusterOperator to identify the root cause and resolve its configuration or resource issues.. Before proceeding with an upgrade, any degraded or failing ClusterOperator must be investigated and resolved because the CVO will block upgrades if core components are not healthy.

Answer

Switch the upgrade channel to 'fast-4.14' to bypass the degraded check.

Answer

Delete the Cluster Version Operator deployment to force a reset of the upgrade state machine.

Answer

Force the upgrade by running 'oc adm upgrade --to=<version> --force-ignore-degraded'.

Question 15

When draining a worker node in OpenShift 4.14, which type of pod running on the node will typically be blocked from eviction unless explicitly ignored or handled?

Accepted Answer

Pods not backed by a controller (naked pods). Pods that are not managed by a ReplicationController, ReplicaSet, Job, DaemonSet, or StatefulSet (often called naked pods) are not safely replicated and require '--force' or special handling during drainage.

Answer

Static pods

Answer

StatefulSet pods

Answer

DaemonSet pods

Question 16

An administrator wants to view the available recommended upgrade paths for an OpenShift 4.14 cluster from the command line. Which command should the administrator run?

Accepted Answer

oc adm upgrade. The 'oc adm upgrade' command displays available updates and recommended upgrade paths for the cluster.

Answer

oc describe upgrade-channel

Answer

oc get clusterversion --recommendations

Answer

oc cluster-version check

Question 17

Which namespace houses the core Cluster Version Operator (CVO) in an OpenShift 4.14 cluster?

Accepted Answer

openshift-cluster-version. The Cluster Version Operator runs in the openshift-cluster-version namespace.

Answer

openshift-machine-api

Answer

openshift-operator-lifecycle-manager

Answer

openshift-config

Question 18

An administrator wants to check whether any worker nodes in an OpenShift 4.14 cluster are currently unschedulable (cordoned). Which command provides this information quickly?

Accepted Answer

oc get nodes. The 'oc get nodes' command displays node status, including whether scheduling is disabled (SchedulingDisabled).

Answer

oc get machineconfigpool --cordoned

Answer

oc describe clusteroperator scheduling

Answer

oc adm show-cordoned

Question 19

An administrator has modified a KubeletConfig resource to adjust the pod eviction thresholds on worker nodes. After applying the change, the administrator observes that some worker nodes are updating while others belonging to a custom worker pool are not. What is the most likely reason?

Accepted Answer

The KubeletConfig's machineConfigPoolSelector does not match the labels on the custom MachineConfigPool.. KubeletConfig resources target specific MachineConfigPools using machineConfigPoolSelector labels. If the custom worker pool does not match the selector, it will not receive the configuration.

Answer

KubeletConfig objects are only supported on control plane nodes in OpenShift 4.14.

Answer

The cluster storage size is insufficient to hold the new kubelet configuration.

Answer

The kubelet service must be manually restarted on every node using SSH.

Question 20

An administrator has successfully installed an Operator via OperatorHub, but the Operator's CSV (ClusterServiceVersion) status is stuck at 'Pending'. Upon investigating, the administrator discovers that the required CustomResourceDefinitions (CRDs) have conflicting versions with a previously deleted Operator. How can the administrator forcefully clean up orphaned CRDs if OLM fails to remove them?

Accepted Answer

Edit the CRD definition and remove any lingering finalizers in 'metadata.finalizers' to allow deletion.. Orphaned or stuck CRDs can be edited to remove finalizers (metadata.finalizers) so Kubernetes can successfully delete them.

Answer

Run 'oc adm prune crds --force' to automatically purge all stuck custom resources.

Answer

Restart the kube-apiserver pods to bypass CRD validation checks.

Answer

Delete the openshift-operator-lifecycle-manager namespace to reset all CRDs.