CKAD Services and Networking Practice Question
Which Service type is used to expose a Service on a static port on each node in the cluster?
⚠ Common exam trap
Many exam-takers confuse NodePort with LoadBalancer, thinking LoadBalancer also exposes a static port on each node, but LoadBalancer actually creates an external LB that routes to NodePort or ClusterIP, not a static port on every node itself.
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
✓
NodePort
NodePort is the correct Service type because it exposes the Service on a static port (in the range 30000-32767) on every node's IP address in the cluster. Traffic sent to any node's IP on that port is forwarded to the Service's ClusterIP and then to the selected Pods, enabling external access without a cloud load balancer.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
ClusterIP
Why it's wrong here
ClusterIP assigns the Service a stable virtual IP that is reachable only inside the cluster's network. It does not create any node-level port binding, so external clients cannot access the Service using a host IP and port. Since the question requires exposing on a static port accessible from outside the cluster, ClusterIP's internal-only reachability makes it incorrect.
- ✗
ExternalName
Why it's wrong here
ExternalName returns a CNAME record pointing to an external DNS name, and it has no selectors, no ports, and no cluster IP. It is used for internal pods to reference an external service via a DNS alias, not to expose an internally defined service on a static port. Because it does not open any port or proxy traffic, it cannot fulfill the requirement.
- ✓
NodePort
Why this is correct
NodePort exposes the Service on a static port in the default range 30000–32767 on every node in the cluster. kube-proxy listens on this NodePort and forwards traffic to the corresponding ClusterIP, which then load-balances to the backing pods. This allows external clients to reach the Service by connecting to any node's IP address with the NodePort, making it the correct Service type for static port exposure.
- ✗
LoadBalancer
Why it's wrong here
LoadBalancer provisions an external load balancer (usually in a cloud provider) that forwards traffic to the Service's NodePort. While it ultimately exposes the Service externally, it works by layering on top of NodePort and typically assigns a dynamic cloud load balancer IP rather than exposing a static port on the nodes themselves. The Service type that actually exposes a static port on each node is NodePort; LoadBalancer adds an indirection and is therefore not the direct answer.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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