DVA-C02 Deployment Practice Question
A company is deploying a containerized application on Amazon ECS using the Fargate launch type. The deployment must ensure zero downtime. Which ECS deployment configuration should be used?
⚠ Common exam trap
Many exam-takers assume a rolling update with high maximum percent (like 200%) guarantees zero downtime, but they overlook that the minimum healthy percent of 50% can still cause a capacity dip, and in-place updates inherently risk serving errors during the transition, whereas blue/green deployments provide true isolation and instant traffic switching.
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
✓
Blue/green deployment using AWS CodeDeploy
Blue/green deployment using AWS CodeDeploy is correct because it creates a separate, fully functional replacement environment (green) alongside the existing one (blue), allowing traffic to be switched instantly after validation. This ensures zero downtime by avoiding in-place updates that could temporarily reduce capacity or serve errors during the transition. For ECS Fargate, CodeDeploy orchestrates the shift using an AppSpec file and can automatically roll back on health check failures.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Rolling update with a minimum healthy percent of 50% and maximum percent of 200%
Why it's wrong here
A rolling update, even with a minimum healthy percentage of 50% and a maximum of 200%, does not guarantee zero downtime for all applications. While it gradually replaces old tasks with new ones, a 50% minimum healthy threshold implies that up to half of the application's capacity could be unavailable at any given moment during the update process. This transient reduction in available capacity or potential for service degradation during task replacement means it cannot reliably ensure continuous availability without any user impact, especially for highly sensitive or stateful applications.
- ✗
Set the task placement strategy to REPLICA
Why it's wrong here
Setting the task placement strategy to REPLICA ensures that a specified number of tasks are maintained and distributed across the cluster, automatically replacing unhealthy tasks. However, REPLICA is a *scheduling strategy* that dictates how tasks are run and maintained, not a *deployment type* that manages the rollout of new application versions. It does not inherently provide mechanisms for pre-testing new versions, gradual traffic shifting, or instant rollback capabilities required for a zero-downtime update of the application code itself.
- ✗
Use the DAEMON scheduling strategy with a deployment circuit breaker
Why it's wrong here
The DAEMON scheduling strategy is designed to run exactly one task on each active EC2 instance in a cluster, typically used for host-level services like logging agents or monitoring tools. While a deployment circuit breaker can detect and halt failing deployments, the DAEMON strategy itself is fundamentally unsuitable for general application deployments requiring zero downtime updates. It focuses on instance-level service presence rather than managing the graceful transition of user traffic between old and new application versions without interruption.
- ✓
Blue/green deployment using AWS CodeDeploy
Why this is correct
Blue/green deployment using AWS CodeDeploy is the most effective strategy for achieving zero-downtime updates for containerized applications on Amazon ECS. This method involves deploying the new application version (green environment) completely separate from the current production version (blue environment). Traffic is then atomically shifted from the blue to the green environment only after the new version has been thoroughly validated, allowing for quick rollback if issues arise, thus ensuring continuous service availability without user impact.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DVA-C02 practice question is part of Courseiva's free Amazon Web Services 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 DVA-C02 exam.