CKA Workloads and Scheduling Practice Question
A StatefulSet 'db' has 3 replicas. You scale it down to 1. In what order are the pods deleted?
⚠ Common exam trap
Test-takers frequently confuse StatefulSet scaling behavior with Deployment scaling, where pods are deleted in random order or simultaneously, leading them to incorrectly choose options A, B, or C instead of the reverse ordinal deletion required by StatefulSet.
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
✓
db-2, db-1, db-0
When a StatefulSet is scaled down, pods are deleted in reverse ordinal order, starting from the highest index. This ensures that the StatefulSet's ordinal and identity guarantees are maintained, as each pod has a unique, stable identity. For a StatefulSet with 3 replicas (db-0, db-1, db-2), scaling to 1 deletes db-2 first, then db-1, leaving db-0 running.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
db-0, db-1, db-2
Why it's wrong here
This sequence represents the ascending order of pod creation when scaling up a StatefulSet from 0 to 3 replicas. During a scale-down operation, Kubernetes terminates pods in the exact reverse order of their creation to maintain data safety and state consistency. Therefore, db-0 and db-1 would not be targeted for deletion before db-2.
- ✗
Random order
Why it's wrong here
Unlike stateless workloads managed by Deployments or ReplicaSets, which terminate pods in an arbitrary or non-deterministic order, StatefulSets enforce strict, ordered pod management. Pods are assigned unique, persistent ordinal indexes that dictate a predictable lifecycle sequence. Consequently, Kubernetes will never delete StatefulSet pods in a random or chaotic fashion.
- ✗
All pods are deleted simultaneously
Why it's wrong here
StatefulSets default to a sequential termination policy where each pod must be completely shut down and deleted before the next one is targeted. Deleting all pods simultaneously would violate the controller's guarantee of orderly termination, potentially causing data corruption in distributed databases. Only when a pod is fully terminated will the controller proceed to the next lower ordinal.
- ✓
db-2, db-1, db-0
Why this is correct
When scaling down a StatefulSet, Kubernetes terminates pods one at a time in reverse ordinal order, starting from the highest index down to the lowest. In this scenario, the controller first gracefully terminates db-2, waits for its complete removal, and then proceeds to terminate db-1 to reach the target of 1 replica (db-0). This predictable, step-by-step reduction ensures that distributed state is safely migrated or persisted.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CKA 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 CKA exam.