KCNA Cloud Native Application Delivery Practice Question
A startup wants to minimize downtime during application updates in Kubernetes. Which deployment strategy should they use?
⚠ Common exam trap
Many candidates confuse 'minimizing downtime' with 'risk mitigation' and pick Canary or Blue/Green, but the question specifically asks for the simplest strategy to minimize downtime during updates, which is RollingUpdate by default in Kubernetes.
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
✓
RollingUpdate
The RollingUpdate strategy is the default in Kubernetes and minimizes downtime by gradually replacing old Pods with new ones while the application remains available. It uses a configurable `maxSurge` and `maxUnavailable` parameters to control the rate of change, ensuring that a specified number of Pods are always serving traffic. This makes it ideal for startups seeking zero-downtime updates without the complexity of additional tooling or infrastructure.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
RollingUpdate
Why this is correct
RollingUpdate replaces pods incrementally, keeping a proportion of replicas available via maxUnavailable and maxSurge, so the Service always has ready endpoints. This satisfies the requirement to minimise downtime during updates without extra tooling or duplicate environments.
- ✗
Canary
Why it's wrong here
Canary shifts a small traffic percentage to the new version, exposing only a subset of users; the old version still serves the rest, so it limits blast radius rather than guaranteeing zero downtime. It suits gradual, risk-managed rollouts with metric validation, not the stem's requirement for uninterrupted availability during updates.
- ✗
Blue/Green
Why it's wrong here
Blue/Green runs two full environments and switches traffic at cutover, so both versions consume double resources during the transition. It suits scenarios needing instant rollback with ample capacity, but the startup's requirement is minimising downtime, which rolling updates achieve without duplicating the entire environment.
- ✗
Recreate
Why it's wrong here
Recreate terminates all existing pods before starting new ones, producing a guaranteed outage window between old and new versions. It suits development or batch workloads where brief unavailability is acceptable, but it directly contradicts the stem's goal of minimising downtime during updates.
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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 TWO of the following are deployment patterns that can be used to update applications with minimal downtime? (Choose two.)
medium- A.DaemonSet deployment
- B.Sidecar deployment
- C.Recreate deployment
- ✓ D.Blue-green deployment
- ✓ E.Canary deployment
Why D: Blue-green deployment (D) is correct because it runs two identical production environments and switches traffic from the old (blue) version to the new (green) version only after the new one is fully deployed and tested, so the cutover is near-instantaneous and downtime is minimal. Canary deployment (E) is correct because it releases the new version to a small subset of users or traffic first, then gradually shifts the remaining traffic once the canary proves healthy, allowing updates with minimal downtime and easy rollback. DaemonSet deployment (A) is not a deployment pattern for updating an application with minimal downtime; it is a Kubernetes workload that ensures one pod runs on every (or selected) node, typically for cluster-level agents. Sidecar deployment (B) is an architectural pattern where a helper container runs alongside the main application container in the same pod, not a strategy for rolling out new application versions. Recreate deployment (C) stops all old instances before starting new ones, which inherently causes downtime, so it does not meet the minimal-downtime requirement.
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.