KCNA Kubernetes Fundamentals Practice Question
You have a Deployment with the following rollout strategy: rollingUpdate: maxSurge: 1, maxUnavailable: 0. What behavior does this configuration enforce?
⚠ Common exam trap
The trap in this question is that candidates often mistakenly think 'maxSurge: 1, maxUnavailable: 0' allows one old pod to be terminated before a new one starts (like a 'one-by-one' strategy). In reality, 'maxUnavailable: 0' forces a new pod to be created and become ready before any existing pod is removed, ensuring zero downtime. This is Kubernetes-specific and differs from simpler rolling update strategies.
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
✓
The rollout will create one additional pod before terminating the old pod, ensuring zero downtime
The rolling update strategy `maxSurge: 1, maxUnavailable: 0` ensures that during the rollout, one additional pod is created above the desired replica count before any existing pod is terminated. This guarantees that the total number of available pods never drops below the desired count, achieving zero downtime. The `maxUnavailable: 0` setting prevents any pod from being taken down until a new one is ready, while `maxSurge: 1` allows one extra pod to be created temporarily.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The rollout will terminate all old pods at once and then create new ones
Why it's wrong here
maxUnavailable: 0 forbids dropping below the desired ready replica count, so old pods cannot all be terminated before replacements exist. It is tempting because Recreate strategy does exactly that, but this Deployment specifies rollingUpdate, which preserves availability throughout the rollout.
- ✗
The rollout will create all new pods first, then delete all old pods
Why it's wrong here
maxSurge: 1 caps extra pods at one above desired count, so Kubernetes adds one new pod at a time rather than all new pods before deleting old ones. It is tempting because a full surge rollout does create replacements ahead of termination, but that requires maxSurge set to the full replica count.
- ✗
The rollout will terminate one old pod before creating a new one
Why it's wrong here
maxUnavailable: 0 prevents terminating any old pod before its replacement is ready, so capacity never dips. It is tempting because terminating one old pod then creating a new one describes a surge-free rolling update, which requires maxUnavailable of at least one and maxSurge of zero.
- ✓
The rollout will create one additional pod before terminating the old pod, ensuring zero downtime
Why this is correct
maxSurge: 1 lets the Deployment add one pod above the desired count, while maxUnavailable: 0 forbids dropping below it. The controller therefore starts a new pod and waits for it to become Ready before terminating an old one, guaranteeing zero downtime.
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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.