KCNA Kubernetes Fundamentals Practice Question
You create a Service of type ClusterIP in the 'default' namespace. You try to reach the Service from a pod in the 'production' namespace using the service name. The connection fails. What is the most likely reason?
⚠ Common exam trap
A common mistake is to think that Kubernetes network policies block cross-namespace traffic, but the actual issue is DNS name resolution. A Service DNS name is only resolvable within the same namespace unless a fully qualified domain name (FQDN) is used.
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
✓
The pod cannot resolve the DNS name because service DNS names are only resolvable within the same namespace
By default, Kubernetes DNS resolves Service names only within the same namespace. A Service named 'my-svc' in the 'default' namespace is resolvable as 'my-svc' only from pods in the 'default' namespace. From a pod in the 'production' namespace, the DNS name must be fully qualified as 'my-svc.default.svc.cluster.local' to be resolved, otherwise the DNS lookup fails, causing the connection to fail.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
The pod cannot resolve the DNS name because service DNS names are only resolvable within the same namespace
Why this is correct
DNS resolution for services is namespace-scoped; you need to use the FQDN.
- ✗
Cross-namespace service access is not allowed by default
Why it's wrong here
It is allowed, but the DNS name must include the namespace.
- ✗
The service has no endpoints
Why it's wrong here
This would cause a different error, like connection refused.
- ✗
The service port is not correctly configured
Why it's wrong here
This would cause issues even within the same namespace.
Visual reference
Go deeper
Related to this question
About these practice questions
Courseiva writes every KCNA question from scratch — 833 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
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.