KCNA Kubernetes Fundamentals Practice Question
Which THREE of the following are valid reasons to use a StatefulSet instead of a Deployment? (Select 3)
⚠ Common exam trap
CNCF often tests the misconception that StatefulSets are only for persistent storage, but the trap here is that candidates overlook the requirement for stable network identities and ordered operations, which are equally critical and distinct from storage needs.
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
✓
You need stable, unique network identifiers (e.g., pod hostnames) that persist across reschedules
StatefulSets provide stable, unique network identifiers (e.g., pod hostnames) that persist across reschedules because each pod gets a fixed ordinal index (e.g., pod-0, pod-1) and a corresponding DNS name (e.g., pod-0.statefulset.namespace.svc.cluster.local). This is essential for applications like databases (e.g., Cassandra, ZooKeeper) that rely on consistent peer discovery and identity, which Deployments cannot guarantee since they assign random pod names and IPs.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
You only need a single instance of the application
Why it's wrong here
A single-instance application can be run with a Deployment with replicas:1; StatefulSet is overkill and not needed.
- ✓
You need stable, unique network identifiers (e.g., pod hostnames) that persist across reschedules
Why this is correct
StatefulSets provide stable network identities (e.g., pod-0, pod-1) that are maintained across rescheduling.
- ✓
You need each pod to have its own persistent storage that is not shared
Why this is correct
StatefulSets can define a VolumeClaimTemplate that creates a unique PersistentVolumeClaim for each pod.
- ✗
You need to deploy a stateless web application with multiple replicas
Why it's wrong here
A stateless web application with multiple replicas is precisely the use case for a Deployment, which manages identical, interchangeable Pods without stable network identities or persistent storage. A StatefulSet would be incorrect here because it enforces ordinal Pod naming and sticky identity, adding unnecessary overhead for a workload that requires neither. The temptation arises because StatefulSets are the correct choice when each replica needs a unique, stable hostname and persistent volume, such as for a database cluster or a distributed queue.
- ✓
You need ordered, graceful deployment and scaling (e.g., pod-0 starts before pod-1)
Why this is correct
StatefulSets support ordered pod creation and termination, which is important for applications like databases.
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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 valid reasons to use a StatefulSet instead of a Deployment? (Select 3)
hard- A.The application needs to be scaled up and down quickly without regard to order.
- ✓ B.The application requires stable unique network identifiers that persist across rescheduling.
- C.The application is stateless and can be replicated arbitrarily.
- ✓ D.Each Pod instance requires its own persistent storage that persists across rescheduling.
- ✓ E.The application must handle graceful shutdown and ordered termination.
Why B: StatefulSets provide stable, unique network identities (e.g., pod-0.svc.cluster.local) that persist across rescheduling, which is essential for applications like databases that rely on hostname-based discovery. Deployments assign random pod names and IPs, making them unsuitable for stateful workloads requiring consistent identity.
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.