CKA Troubleshooting Practice Question
A pod is in 'Pending' state. 'kubectl describe pod' shows: '0/3 nodes are available: 1 Insufficient memory, 2 node(s) had taint {node-role.kubernetes.io/control-plane: }, that the pod didn't tolerate.' Which THREE actions would resolve the issue? (Choose three)
⚠ Common exam trap
Be careful with scheduling issues. A pod only needs one suitable node to schedule. You do not need to resolve the issues on all 3 nodes; resolving the issue on either the memory-constrained node (Option B) OR the tainted nodes (Options A or D) is sufficient to transition the pod out of the 'Pending' state.
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
✓
Remove the taint from the control-plane nodes.
The pod cannot be scheduled because one node lacks memory and two nodes have a control-plane taint. Any single action that resolves either the memory issue (decreasing memory request) or the taint issue (removing taint or adding toleration) will make a node available. Since the question asks for three actions, A, B, and D are the correct choices as each independently resolves the scheduling block. Options C and E do not address the reported problems.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Remove the taint from the control-plane nodes.
Why this is correct
Removing the taint from control-plane nodes makes those nodes schedulable for the pod, provided they have sufficient memory. This is a valid solution.
- ✓
Decrease the memory request of the pod.
Why this is correct
Decreasing the memory request reduces the pod's memory requirement, making the node with insufficient memory available. This is a valid solution.
- ✗
Increase the CPU request of the pod.
Why it's wrong here
Increasing CPU request does not address the memory insufficiency or taint, so it does not help.
- ✓
Add a toleration to the pod for the control-plane taint.
Why this is correct
Adding a toleration for the control-plane taint allows the pod to be scheduled on those nodes, assuming they have enough memory. This is a valid solution.
- ✗
Add a node selector to the pod that matches the control-plane nodes.
Why it's wrong here
Adding a node selector that matches control-plane nodes does not help because those nodes still have the taint that the pod does not tolerate.
Visual reference
Go deeper
Related to this question
Learn chapter
Kubernetes Architecture Overview
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.
Key term
Network Policies
A Kubernetes resource that controls how pods communicate with each other and with other network endpoints, acting as a firewall for pod-to-pod traffic.
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JA
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.