Troubleshooting And Diagnostics

An OpenShift administrator needs to investigate a pod that is failing with an 'OOMKilled' exit code. Which command reveals the memory limit configuration and historical usage right before the crash?

An administrator is troubleshooting a failing MachineConfig update in an OpenShift cluster. The MachineConfigPool 'worker' is degraded and reports that a node is failing to apply the rendered-worker configuration. Which log stream is critical for determining why the Machine Config Daemon failed to update system files on the target node?

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

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?

An application pod is failing its liveness probe and continuously restarting. Where can an administrator quickly check the reason for the liveness probe failure?

An administrator notices that the Cluster Version Operator (CVO) is blocked during an upgrade because a cluster operator is missing version annotations. Which command allows checking the current status and payload version of the CVO?

A pod fails to start with a 'CreateContainerConfigError' error message. What is the most common cause of this error that an administrator should investigate?

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'?

A container inside a pod is failing with 'ImagePullBackOff'. The administrator verifies the image tag exists. What is the next most logical troubleshooting step to check authentication or registry access?

During a troubleshooting session on a degraded cluster operator, an administrator finds that the operator's operand configuration is controlled by a Custom Resource (CR). Where is the most reliable place to look for error status messages reported by the operator controller loop regarding this CR?

An administrator wants to verify if all required cluster operators are available and not degraded after an installation. Which command provides this summary?

An application pod is running, but HTTP requests to the service are returning '502 Bad Gateway'. The administrator wants to check if the endpoints controller has populated the Service with active pod IP addresses. Which command verifies this?

An OpenShift cluster node has experienced kernel panics due to a faulty third-party kernel module. The administrator needs to review the kernel crash logs (vmcore or kdump logs) stored on the node. Where are these logs typically written on a CoreOS worker node?

The 'dns' ClusterOperator is reporting Degraded=True because CoreDNS pods are failing health checks. The administrator suspects DNS request loops or upstream forwarding failures. Which log source is most effective for diagnosing CoreDNS resolution errors?

An administrator is troubleshooting a certificate expiration issue that has broken communication between the kubelet and the API server. Where are the kubelet client certificates stored on a worker node that can be inspected via an oc debug session?

An administrator notices that the Ingress Operator is failing to deploy routers because of a persistent validation error in the Default IngressController resource. How can the administrator inspect the exact validation schema failure reported by the operator?

An administrator needs to check the IP address and network status assigned to a running pod. Which command displays this information quickly?

An administrator wants to view the last 50 lines of logs for a pod named 'api-server-xyz' and keep the stream open for new log entries. Which command should they use?

The cluster monitoring stack is failing because Prometheus pods in the openshift-monitoring namespace are crashing due to disk space exhaustion on the Prometheus PersistentVolume. How can the administrator inspect the current disk usage inside the Prometheus container?

An OpenShift cluster's Ingress controller is failing to route external traffic because the router pods are crashing with 'Bind: address already in use'. What is the most likely cause that an administrator should investigate?

An application team reports that their application cannot connect to an external database due to a firewall blocking port 3306. The administrator wants to test network connectivity from inside a running application pod to the external database host. Which tool can they run using 'oc exec'?

An administrator needs to list all persistent volume claims in the cluster that are currently stuck in the 'Pending' state. Which command can be combined with grep or custom formatting to identify them?

An OpenShift cluster administrator receives an alert that etcd disk fsync durations are excessively high. Which performance metric is the etcd diagnostic tool measuring when evaluating disk latency?

An administrator wants to check the logs of the Cluster Version Operator to see why an upgrade failed. In which namespace does the CVO run?

An administrator needs to drain a worker node safely for hardware maintenance, but some pods have local emptyDir storage that would be permanently deleted. Which flag must be added to the drain command to allow eviction of these pods?

An administrator wants to check the detailed configuration and current status of a specific Route named 'my-app-route'. Which command provides this?

The OpenShift SDN (or OVN-Kubernetes) network plugin reports a failure. The administrator needs to inspect the iptables rules on a worker node to verify packet mangling and NAT configurations. How can they view the host's iptables rules?

An administrator needs to verify which user account or service account they are currently logged into the OpenShift cluster with. Which command provides this information?

An OpenShift cluster administrator notices that API requests are taking an excessively long time to complete. They suspect etcd database bloat due to excessive ConfigMap creations. Which etcd maintenance command can be run inside an etcd pod to reclaim storage space after compaction?

An administrator receives an alert that the Cluster Monitoring Operator is degraded because Prometheus cannot scrape metrics from a custom application namespace. Where should the administrator check to verify the ServiceMonitor configuration targeting the application?

An administrator is troubleshooting a certificate signing request (CSR) that is stuck in the Pending state for a newly added worker node. Which command should they use to approve the pending CSR?

An administrator wants to check the cluster-wide resource consumption of nodes (CPU and Memory percentages). Which command provides this tabular overview?

An administrator is investigating pod crash loops in a namespace. Which TWO commands are most useful for gathering initial diagnostic data about the crashing pods? (Choose TWO)

An administrator notices that the 'storage' ClusterOperator is degraded. Which TWO resources or logs should be inspected to diagnose the underlying CSI driver or provisioner failure? (Choose TWO)

An OpenShift cluster node is reporting High CPU and Memory pressure. Which THREE commands or tools can an administrator use to investigate resource bottlenecks on that node? (Choose THREE)

An administrator is troubleshooting a deployment where pods fail to pull container images. Which TWO potential issues should be checked? (Choose TWO)

An administrator needs to troubleshoot DNS resolution failures inside an application namespace. Which THREE resources or commands should they check? (Choose THREE)

An administrator wants to check cluster networking and SDN communication. Which TWO commands can be used to gather network-related diagnostic information? (Choose TWO)

An administrator is diagnosing why an authentication token exchange is failing for cluster users. Which THREE sources provide relevant error logs and status information? (Choose THREE)

An OpenShift cluster upgrade has failed because a MachineConfigPool is degraded. Which THREE actions or commands can an administrator perform to diagnose the root cause of the MachineConfigPool degradation? (Choose THREE)

During etcd troubleshooting, an administrator suspects quorum loss or follower synchronization issues. Which THREE commands or etcdctl actions performed inside an etcd pod can verify etcd health and cluster state? (Choose THREE)

An administrator notices that a node has been automatically cordoned and drained by the cluster. Which THREE places should the administrator inspect to find the reason for the node eviction or failure? (Choose THREE)

An OpenShift cluster operator is stuck in a Progressing state during an update. Which THREE diagnostic steps help determine why the operator reconciliation loop is blocked? (Choose THREE)

An administrator wants to check the status of all api-server instances in the cluster. Which TWO commands are helpful? (Choose TWO)

An administrator wants to inspect cluster events filtered by warning type. Which TWO commands or techniques can help? (Choose TWO)

An administrator wants to verify node health and readiness across the cluster. Which TWO commands provide this information? (Choose TWO)

An administrator needs to troubleshoot why an OLM (Operator Lifecycle Manager) managed operator installation is failing. Which THREE resources should be inspected? (Choose THREE)

An administrator is troubleshooting a pod that is repeatedly restarting in the 'app-prod' namespace. The pod's restart count is high, and the administrator needs to determine the exit code of the last terminated container to identify whether the process exited due to an application error or was killed by the OOM killer. Which single command provides this information most directly?

An administrator notices that a Deployment named 'webapp' in the namespace 'production' is not reaching its desired replica count. Running 'oc get deployment webapp -n production' shows READY 2/3 but no events appear on the Deployment itself. The administrator wants to determine why the third ReplicaSet pod cannot be scheduled. Which command best reveals the scheduling failure reason?

An administrator notices that the `openshift-apiserver` cluster operator reports `Available=True` but `Progressing=True` with the message `APIServerDeploymentProgressing: deployment/openshift-apiserver: 1/3 pods ready`. The administrator wants to determine which specific pod is not ready and why. Which command provides the most direct diagnostic information about the individual pod's readiness?

An administrator runs 'oc debug node/worker-1' and gets a shell in the debug pod, but when they try to run 'crictl ps' to list running containers on the node, the command is not found. They confirm the node's kubelet is healthy and workloads are running. What is the correct explanation and fix?

An administrator is troubleshooting a pod that fails to schedule and remains in `Pending` state. The administrator runs `oc describe pod` and sees the event `0/9 nodes are available: 9 node(s) had taint {node-role.kubernetes.io/master: }, that the pod didn't tolerate.` What is the most likely cause?

An administrator must determine why a namespace named 'batch' is stuck in the Terminating state and has remained so for over an hour. They need to identify what is blocking finalization so it can be cleared. (Choose two.)

An administrator is diagnosing an application pod that repeatedly restarts. The pod's container shows a Completed exit with code 0 in its last termination state, yet Kubernetes restarts it anyway. The Deployment specifies 'restartPolicy: Always'. What is the correct interpretation?

An administrator suspects a pod named 'cache-0' in namespace 'data' is being evicted due to node memory pressure. They want to confirm the eviction reason and see the kubelet's decision. Which command most directly provides the eviction evidence?

An administrator is troubleshooting a node that is reporting `NotReady` in an OpenShift cluster. The administrator runs `oc get nodes` and sees the node's status as `NotReady,SchedulingDisabled`. Which command should the administrator use to view the node's conditions and determine the specific reason for the NotReady state?