CKA Practice Question: Cluster Architecture, Installation and Configuration
An administrator runs 'kubectl get pods' and sees a pod stuck in 'Pending' state. Which of the following is NOT a typical cause?
⚠ Common exam trap
Test-takers frequently confuse scheduling failures (which cause 'Pending') with runtime configuration errors (which cause 'CrashLoopBackOff' or 'Error'), leading them to incorrectly think a missing ConfigMap could prevent scheduling.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
A required ConfigMap does not exist
A missing ConfigMap does not prevent a pod from being scheduled; it only causes the pod to fail at runtime when it tries to mount or use the ConfigMap. The 'Pending' state specifically indicates that the pod has not been scheduled to a node, which is a scheduling issue, not a runtime configuration issue. Therefore, a missing ConfigMap is not a typical cause of a pod stuck in 'Pending'.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Insufficient CPU or memory resources on any node
Why it's wrong here
If node resources were insufficient, the Kubernetes scheduler would repeatedly attempt to place the Pod and emit events such as "0/3 nodes are available: insufficient cpu" or "insufficient memory". The Pod would remain in the Pending phase while waiting for resources, but a missing ConfigMap does not influence node resource availability or scheduling. Instead, a missing ConfigMap prevents the kubelet from creating the container, producing a different failure mode like CreateContainerConfigError. Therefore, this option describes a separate, plausible cause that is not the one in question.
- ✗
PersistentVolumeClaim is pending and not bound
Why it's wrong here
A PersistentVolumeClaim in Pending state would indeed block the Pod from starting, because the kubelet cannot mount a volume that has not been bound to a PersistentVolume. This would leave the Pod in Pending with events indicating that the PVC is waiting to be bound. However, a missing ConfigMap is not related to volume provisioning; it is a configuration error that surfaces at container creation time when the kubelet attempts to populate env vars or mount the ConfigMap. Thus, while a pending PVC is a possible cause of a stuck Pod, it is not the correct answer here because the Pod's issue stems from a missing ConfigMap, not a storage problem.
- ✓
A required ConfigMap does not exist
Why this is correct
A required ConfigMap that does not exist causes the kubelet to fail when it tries to start the container, because it cannot retrieve the referenced keys for environment variables or volume mounts. The typical event is: "Error: configmap \"<name>\" not found" and the Pod status may be CreateContainerConfigError or ContainerCreating. This is exactly the scenario described: the Pod appears stuck, yet the underlying cause is a configuration object that is missing, not a scheduling or resource issue. Therefore, this is the correct answer.
- ✗
Node selector labels do not match any node
Why it's wrong here
When a Pod has a node selector that matches no node, the scheduler cannot find a suitable node and leaves the Pod in Pending with events like "0/4 nodes are available: 4 node(s) didn't match node selector". This is a scheduling-level failure, completely separate from container configuration. A missing ConfigMap does not affect node selection; the scheduler will still successfully assign the Pod to a node based on labels and resource requirements. The ConfigMap error only occurs later, during container creation, so this option describes a different and incorrect cause for the Pod being stuck.
Go deeper
Related to this question
Learn chapter
Troubleshooting Cluster and Node Issues
Key term
ConfigMaps
A ConfigMap is a Kubernetes object that lets you store configuration data separately from your application code, so you can change settings without rebuilding or redeploying your container images.
Key term
kubectl Command Reference
kubectl is the command-line tool used to interact with and manage Kubernetes clusters by sending commands to the Kubernetes API.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CKA practice question is part of Courseiva's free CNCF certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the CKA exam.