KCNA Cloud Native Architecture Practice Question
A retail company runs its e-commerce platform on Kubernetes. During a flash sale, the application experiences high latency. The team notices that the database pods are CPU-bound and the application pods are waiting on database responses. Which architectural change would best address this bottleneck?
⚠ Common exam trap
CNCF often tests the misconception that scaling application pods (Option C) is a universal fix for performance issues, but here it would amplify the database bottleneck rather than resolve it.
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
✓
Implement read replicas for the database and configure the application to use them for read operations.
The bottleneck is caused by the database being CPU-bound, meaning it cannot process requests fast enough. Implementing read replicas offloads read queries from the primary database, reducing its CPU load and allowing it to handle write operations more efficiently. The application can be configured to route read operations to the replicas, which directly addresses the latency caused by waiting on database responses.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Change the database service type from ClusterIP to NodePort.
Why it's wrong here
Changing ClusterIP to NodePort only alters how external clients reach the Service; it does not relieve CPU saturation on the database pods, so application pods still wait. NodePort suits exposing a Service on each node's IP for external access, not resolving database compute bottlenecks.
- ✓
Implement read replicas for the database and configure the application to use them for read operations.
Why this is correct
Read replicas offload read queries from the primary database, distributing CPU load across additional nodes so the CPU-bound database pods are no longer saturated. Configuring the application to route reads to replicas directly reduces the wait time for application pods, addressing the bottleneck identified during the flash sale.
- ✗
Increase the number of application pod replicas.
Why it's wrong here
Adding application replicas multiplies the number of clients waiting on the same CPU-bound database, worsening contention. Horizontal scaling of stateless application pods suits handling increased request volume when the backend has spare capacity, not when the database itself is the saturated component.
- ✗
Store database configuration in a ConfigMap to improve startup time.
Why it's wrong here
A ConfigMap supplies configuration data to pods; it does not affect CPU consumption or query throughput, so the database remains CPU-bound. ConfigMaps suit decoupling environment-specific settings from container images, not scaling compute for a saturated database during traffic spikes.
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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.