EX280 Cluster Installation And Management — Timed 10 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?

10 minute time limit — choose an answer to begin.

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.