SOA-C02 Deployment, Provisioning, and Automation Practice Question
An organization is using AWS CloudFormation to manage its infrastructure. The SysOps administrator wants to update a stack that includes an Amazon RDS DB instance. The update requires changing the DB instance class. However, the administrator wants to minimize downtime. What should the administrator do?
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
✓
Enable Multi-AZ on the DB instance (if not already enabled) before performing the stack update.
Enabling Multi-AZ allows the RDS instance to have a standby in a different Availability Zone. When updating the DB instance class, CloudFormation can modify the standby first, then fail over to it, minimizing downtime. Options A, C, and D are incorrect: A (DeletionPolicy) controls resource retention on stack deletion, not updates; C (ApplyImmediately) may cause a brief outage; D (read replica promotion) is for scaling reads, not for minimizing downtime during instance class changes.
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 CloudFormation's 'DeletionPolicy' attribute to retain the database during updates.
Why it's wrong here
The 'DeletionPolicy' attribute only controls what occurs when a logical resource is removed from a stack or the stack is deleted—values like 'Retain' preserve the underlying RDS instance and its data, but they have no effect on resources that are being updated. An in-place modification such as changing the DB instance class will still occur, and the database will still be unavailable during that operation. Therefore, this attribute provides no downtime minimization for an instance class update.
- ✓
Enable Multi-AZ on the DB instance (if not already enabled) before performing the stack update.
Why this is correct
Enabling Multi-AZ gives the DB instance a standby replica in a different Availability Zone, which RDS can fail over to during maintenance. When a stack update changes the DB instance class, RDS applies the modification to the standby first, performs a failover, and then updates the former primary—this keeps the database available during the transition. Because the failover only causes a brief connection interruption rather than a full shutdown, Multi-AZ is the correct way to minimize downtime during an instance class update.
- ✗
Update the stack directly with 'ApplyImmediately' set to true.
Why it's wrong here
The 'ApplyImmediately' property tells CloudFormation to apply the DB instance class change during the update instead of waiting for the next maintenance window. On a single-AZ instance, modifying the instance class still requires RDS to stop and restart the database, so you experience an outage for the entire modification period. This setting simply schedules the change; it does not eliminate or even reduce the downtime caused by the instance class change.
- ✗
Create a read replica, promote it, and then delete the original DB instance.
Why it's wrong here
Creating a read replica and promoting it is a method to scale read capacity or recover from disasters, but it does not minimize downtime during a DB instance class update in a CloudFormation stack update.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This SOA-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 SOA-C02 exam.