KCNA Kubernetes Fundamentals Practice Question
A cluster administrator wants to ensure that a specific Pod always runs on a node with an SSD. The node has the label disktype=ssd. Which Kubernetes feature should the administrator use?
⚠ Common exam trap
Candidates often confuse node selection mechanisms, such as using taints and tolerations or affinity when a simple nodeSelector is sufficient.
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
✓
nodeSelector
nodeSelector is the simplest way to constrain a Pod to nodes with specific labels. By specifying a label like disktype=ssd, the scheduler only considers nodes that have that label. This directly satisfies the requirement of running on an SSD node.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Pod affinity
Why it's wrong here
Pod affinity allows you to constrain a Pod to nodes based on labels of other Pods already running on those nodes, not based on node labels themselves. It is used for co-locating Pods, not for selecting nodes by hardware attributes like disktype.
- ✗
Taints and tolerations
Why it's wrong here
Taints are applied to nodes to repel Pods, and tolerations allow Pods to be scheduled on tainted nodes. They are used for exclusion, not for selecting nodes based on hardware. While they can influence scheduling, they do not directly match Pods to labeled nodes.
- ✗
Resource requests and limits
Why it's wrong here
Resource requests and limits define CPU and memory requirements for a Pod, which the scheduler uses to find nodes with sufficient capacity. They do not consider node labels such as disktype. Thus, they cannot ensure placement on an SSD node.
- ✓
nodeSelector
Why this is correct
nodeSelector is a simple field in the Pod spec that specifies a map of key-value pairs. The Pod will only be scheduled on nodes that have all the specified labels. Here, setting nodeSelector: disktype: ssd ensures the Pod lands on an SSD node.
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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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