The correct answer is to use a blue/green deployment by creating a new stack with the larger instance type and updating the application to point to the new database. This approach is necessary because CloudFormation in-place updates to an RDS instance type require a database reboot, which causes downtime; a blue/green deployment avoids this by provisioning the upgraded instance in a separate, parallel environment (green) while the original (blue) continues serving traffic, then performing a seamless cutover. On the AWS Certified Developer Associate DVA-C02 exam, this question tests your understanding of zero-downtime deployment strategies versus the default CloudFormation behavior, where changing the DBInstanceClass triggers a replacement or modification that interrupts service. A common trap is assuming that removing the DeletionPolicy or using a simple update will suffice, but any change to the instance class inherently requires a reboot. Memory tip: think "Blue stays live while Green gets the upgrade" — you never modify the running database directly.
DVA-C02 Deployment Practice Question
This DVA-C02 practice question tests your understanding of deployment. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A developer is using AWS CloudFormation to deploy a stack that includes an Amazon RDS DB instance. The developer wants to update the DB instance to a larger instance type without causing downtime. The current template has DeletionPolicy set to 'Delete'. What should the developer do?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Use a blue/green deployment by creating a new stack with the larger instance type and updating the application to point to the new database.
Option B is correct because a blue/green deployment allows you to create a new stack with the larger DB instance type in a separate environment (green), then switch the application traffic to the new database with minimal downtime. This approach avoids the downtime associated with in-place modifications, as CloudFormation updates to RDS instance types typically require a reboot, which causes an outage. By using a blue/green deployment, the developer can validate the new instance and cut over seamlessly.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Take a snapshot of the DB instance and restore it to a larger instance type.
Why it's wrong here
Restoring from snapshot causes downtime.
✓
Use a blue/green deployment by creating a new stack with the larger instance type and updating the application to point to the new database.
Why this is correct
Blue/green deployment minimizes downtime by switching to a new stack.
Related concept
Read the scenario before looking for a memorised answer.
✗
Change the DeletionPolicy to 'Retain' and update the stack.
Why it's wrong here
DeletionPolicy only affects deletion, not updates.
✗
Create a read replica with the larger instance type and promote it.
Why it's wrong here
Promoting a read replica can cause downtime and data loss.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates assume CloudFormation stack updates can resize RDS instances without downtime, but in reality, modifying the DBInstanceClass requires a reboot, making blue/green deployments the only zero-downtime option among the choices.
Detailed technical explanation
How to think about this question
Blue/green deployments for RDS often use DNS switching or application-level connection pooling to redirect traffic with minimal disruption. Under the hood, CloudFormation stack updates for RDS instance types trigger a ModifyDBInstance API call with the ApplyImmediately parameter, which forces a reboot; blue/green deployments avoid this by provisioning a parallel stack and using Route53 weighted records or an external load balancer for cutover. In real-world scenarios, this approach is critical for production databases where even seconds of downtime can impact SLAs.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A company's IT admin needs to give a contractor read-only access to production logs without sharing account credentials. Using role-based access control (RBAC) and temporary scoped permissions — not a permanent shared password — is the correct pattern. Questions like this test whether you can apply least-privilege access across cloud identity services.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Deployment — This question tests Deployment — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Use a blue/green deployment by creating a new stack with the larger instance type and updating the application to point to the new database. — Option B is correct because a blue/green deployment allows you to create a new stack with the larger DB instance type in a separate environment (green), then switch the application traffic to the new database with minimal downtime. This approach avoids the downtime associated with in-place modifications, as CloudFormation updates to RDS instance types typically require a reboot, which causes an outage. By using a blue/green deployment, the developer can validate the new instance and cut over seamlessly.
What should I do if I get this DVA-C02 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
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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. A developer is using AWS CloudFormation to deploy a stack that includes an Amazon RDS DB instance. The developer wants to update the stack to change the DB instance class. The update fails because CloudFormation cannot modify the DB instance class without replacement. The developer needs to complete the update with minimal downtime. What should the developer do?
hard
A.Delete the stack and create a new stack with the new DB instance class.
✓ B.Use a custom resource with an AWS Lambda function to perform the modification, ensuring data is backed up and downtime is minimized.
C.Update the stack and disable rollback on failure.
D.Update the stack using a change set, then execute it.
Why B: Option B is correct because a custom resource backed by an AWS Lambda function allows you to perform the RDS DB instance class modification outside of CloudFormation's direct lifecycle, enabling you to use the 'ApplyImmediately' parameter to minimize downtime. CloudFormation's native update for RDS DB instance class requires replacement (i.e., a new physical resource), which causes downtime; a custom resource can orchestrate a 'modify-db-instance' API call with '--apply-immediately' to change the class in-place with only a brief reboot.
Last reviewed: Jun 24, 2026
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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.
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