KCNA Kubernetes Fundamentals Practice Question
Which THREE statements about Labels and Selectors are correct?
⚠ Common exam trap
CNCF often tests the distinction between labels and annotations, trapping candidates who assume annotations can also be used for selection, when in fact only labels support selector-based filtering.
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
✓
Services use selectors to determine which Pods receive traffic
A Kubernetes Service uses a label selector to identify which Pods should receive traffic. When a Service is created with a selector matching certain labels, the endpoint controller dynamically updates the Service's Endpoints object to include the IP addresses of all Pods with those labels, enabling traffic routing.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Services use selectors to determine which Pods receive traffic
Why this is correct
Services use label selectors to route traffic to matching Pods.
- ✓
Selectors are used by Deployments to identify the Pods they manage
Why this is correct
Deployments use label selectors in their spec to manage ReplicaSets and Pods.
- ✓
Labels can be used to organize and select subsets of objects
Why this is correct
Labels are used to identify and group objects.
- ✗
Labels must be unique within a namespace
Why it's wrong here
Labels are not unique; multiple objects can have the same labels.
- ✗
Annotations are used for identification and selection
Why it's wrong here
Annotations are for non-identifying metadata, not used for selection.
Go deeper
Related to this question
Learn chapter
Kubernetes Overview and Core Components
Key term
ReplicaSet and Replication
A ReplicaSet ensures a specified number of identical pod instances are running at all times in Kubernetes, using replication to maintain availability and stability.
Key term
Kubernetes API Primitives
Kubernetes API Primitives are the basic building blocks that the Kubernetes API uses to represent and manage the state of a cluster, such as Pods, Services, Deployments, and Namespaces.
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Same concept, more angles
1 more way this is tested on KCNA
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. Which THREE of the following are true about Kubernetes labels and selectors?
hard- A.Labels are encrypted at rest by default
- ✓ B.Set-based selectors support operators like 'In' and 'NotIn'
- ✓ C.Selectors can be used by Services to identify which pods to route traffic to
- D.Labels are immutable after creation
- ✓ E.Labels can be used to organize and select subsets of objects
Why B: Kubernetes set-based selectors support operators like 'In', 'NotIn', 'Exists', and 'DoesNotExist', allowing more flexible matching than equality-based selectors. This is defined in the Kubernetes API specification for label selectors, enabling complex filtering of resources.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This KCNA 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 KCNA exam.