CKAD Services and Networking Practice Question
A Pod needs to access an external database at db.example.com:3306. Which Service type allows Pods to resolve a cluster-local name to this external address?
⚠ Common exam trap
Candidates often confuse ExternalName with ClusterIP, thinking any Service can resolve external names, but only ExternalName provides a CNAME-based DNS alias without proxying traffic.
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
✓
ExternalName
The ExternalName Service type maps a cluster-local DNS name (e.g., `my-db.default.svc.cluster.local`) to an external DNS name (`db.example.com`) using a CNAME record. This allows Pods to resolve the service name to the external database address without needing to modify application code or use an external endpoint.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
ExternalName
Why this is correct
An ExternalName Service maps a Service's DNS name to an external fully-qualified domain name. When queried, CoreDNS returns a CNAME record directly to the target, such as db.example.com, so pods can reach the database through an in-cluster alias without any proxy or selector.
- ✗
LoadBalancer
Why it's wrong here
A LoadBalancer Service provisions a cloud-provider load balancer with a public IP to expose an internal set of pods to external traffic. It does not resolve or alias external DNS names; it is an ingress mechanism, not a DNS-level redirect, so it cannot make db.example.com reachable as a cluster-local name.
- ✗
NodePort
Why it's wrong here
NodePort exposes a Service on a static high-port on every node, allowing external clients to connect using nodeIP:port. It only opens a port to reach backend pods; it has no DNS resolution capability and cannot create a CNAME or otherwise map a Service name to an external database.
- ✗
ClusterIP
Why it's wrong here
ClusterIP is the default Service type, assigning a virtual IP that is only routable inside the cluster for pod-to-pod communication. It has no link to external DNS — creating a ClusterIP Service for db.example.com would merely allocate an internal IP that cannot forward traffic to the database.
Visual reference
Go deeper
Related to this question
About these practice questions
One of 826 original CKAD practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CKAD 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 CKAD exam.