KCNA Container Orchestration Practice Question
A cluster administrator notices that a Pod scheduled on a node is stuck in the Pending state. The Pod requests 8 CPU cores, but the node has only 4 allocatable CPU cores. The scheduler logs show a FailedScheduling event with the message 'Insufficient cpu'. Which action will allow the Pod to be scheduled without reducing its CPU request?
⚠ Common exam trap
The trap here is assuming that preemption or tolerations can overcome a node's total CPU capacity limit.
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
✓
Add a new node to the cluster that has at least 8 allocatable CPU cores and ensure the Pod's scheduling constraints match that node.
The scheduler filters nodes based on available allocatable resources. A Pod requesting 8 CPU cores cannot fit on a node with only 4 allocatable cores, regardless of taints or priority. Adding a node with sufficient CPU capacity and matching scheduling constraints resolves the issue without altering the Pod's request. Reducing the request would work but violates the scenario constraint.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Create a PriorityClass with a high value and assign it to the Pod to preempt other workloads.
Why it's wrong here
Preemption can evict lower-priority Pods to free resources, but the node has only 4 allocatable CPU cores total. Even after evicting all other Pods, the node cannot provide 8 cores. Preemption cannot overcome a hard capacity limit. A new node or a larger node is required.
- ✗
Reduce the Pod's CPU request to 4 cores so it fits on the existing node.
Why it's wrong here
Changing the CPU request would allow scheduling, but the scenario explicitly asks for an action that does not reduce the Pod's CPU request. The application may need 8 cores to function correctly. This option violates the stated constraint and does not preserve the original resource requirement.
- ✓
Add a new node to the cluster that has at least 8 allocatable CPU cores and ensure the Pod's scheduling constraints match that node.
Why this is correct
The scheduler cannot place the Pod because no node has enough allocatable CPU. Adding a node with sufficient capacity and compatible labels or taints allows the scheduler to bind the Pod there. This addresses the root cause without changing the Pod's resource request. Other options either ignore the capacity shortage or alter the request.
- ✗
Add a toleration to the Pod so it can be scheduled on a tainted node.
Why it's wrong here
Tolerations only affect taint-based filtering. The FailedScheduling message indicates insufficient CPU, not a taint mismatch. Adding a toleration does not create CPU capacity on any node. The Pod would still be unschedulable because no node has 8 allocatable cores. This option misdiagnoses the cause.
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Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official CNCF exam blueprint
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