DVA-C02 Troubleshooting and Optimization Practice Question
A developer is deploying a new version of a Lambda function using an alias for blue/green deployment. Traffic is gradually shifted to the new version. During the shift, a high error rate is observed. What should the developer do to minimize impact?
⚠ Common exam trap
Test-takers frequently think manual reversion (Option B) is the simplest fix, but the exam emphasizes automated rollback strategies (like canary deployments with alarms) as the best practice for minimizing impact during blue/green deployments.
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
✓
Configure the alias with a canary deployment and an error rate alarm for automatic rollback.
It automates the rollback process using AWS CodeDeploy's canary deployment with an Amazon CloudWatch alarm on the error rate. When the alarm triggers, CodeDeploy automatically shifts traffic back to the previous version, minimizing impact without manual intervention. This is the recommended approach for safe blue/green deployments with Lambda aliases.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Use the Lambda function's provisioned concurrency to pre-warm the new version.
Why it's wrong here
Provisioned concurrency allocates a pre-initialized number of execution environments for a Lambda function version, significantly reducing cold start latency. While beneficial for performance-critical applications, it does not provide any mechanism for safe deployment strategies like gradual traffic shifting or automatic rollback in case of errors. Therefore, it doesn't address the core requirement of a controlled deployment with error detection and recovery.
- ✗
Manually revert the alias to point back to the old version.
Why it's wrong here
Manually reverting a Lambda alias to point back to an older version is a reactive and labor-intensive process. This approach introduces significant delay between error detection and resolution, potentially prolonging service disruption for users. Furthermore, manual steps are inherently prone to human error, which can exacerbate the issue rather than resolve it efficiently or automatically.
- ✓
Configure the alias with a canary deployment and an error rate alarm for automatic rollback.
Why this is correct
Configuring a Lambda alias with a canary deployment allows for gradual shifting of traffic to the new function version, starting with a small percentage. Integrating this with an Amazon CloudWatch error rate alarm enables automatic rollback: if the new version's error rate exceeds a predefined threshold during the canary phase, the alias automatically reverts all traffic to the stable old version. This strategy minimizes the impact of potential issues by detecting them early and automating recovery.
- ✗
Delete the new version and redeploy after fixing the issue.
Why it's wrong here
Deleting a new Lambda function version and then redeploying after fixing an issue is a highly disruptive and inefficient approach. This method would likely result in significant downtime or service interruption for users while the new version is being fixed and redeployed. It lacks any mechanism for graceful degradation or immediate recovery, making it unsuitable for maintaining high availability during deployments.
Quick reference
Cloud Service Model Comparison
| Model | You Manage | Provider Manages | Examples |
|---|---|---|---|
| IaaS | OS, runtime, apps, data | Hardware, hypervisor, networking | EC2, Azure VMs, GCP Compute Engine |
| PaaS | Apps and data | OS, runtime, middleware, hardware | Elastic Beanstalk, Azure App Service |
| SaaS | Data and settings only | Everything else | Microsoft 365, Salesforce, Workday |
| FaaS / Serverless | Function code only | Infra, scaling, runtime | Lambda, Azure Functions, Cloud Run |
| CaaS | Containers and apps | Kubernetes, OS, hardware | EKS, AKS, GKE |
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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.