SOA-C02 Reliability and Business Continuity Practice Question
An organization is using AWS CloudFormation to deploy infrastructure. The SysOps administrator needs to ensure that if a stack update fails, the stack automatically rolls back to the last known good state. Which stack update option should be configured?
⚠ Common exam trap
Candidates often confuse 'Rollback on failure' with 'Disable rollback' or think that change sets or stack policies handle rollback behavior, when in fact only the rollback configuration directly controls automatic recovery from failed updates.
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
✓
Rollback on failure
CloudFormation's 'Rollback on failure' option, enabled by default, automatically reverts a stack to its last known good state if a stack update fails. This ensures that failed updates do not leave the infrastructure in an inconsistent or partially deployed state, maintaining reliability and business continuity.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Disable rollback
Why it's wrong here
Choosing 'Disable rollback' explicitly turns off the automatic recovery mechanism. If an update fails while rollback is disabled, CloudFormation leaves the stack in the UPDATE_FAILED state and does not restore any resources that were already modified during the attempted update. This is the opposite of the desired behavior, because it leaves failed changes in place rather than reverting to the last known good configuration.
- ✗
Change sets
Why it's wrong here
Change sets are a planning tool: they provide a preview of the resources and properties that will be changed before you execute an update. They do not, however, have any influence on failure handling once the update is executed. A change set never triggers a rollback; it simply lets you inspect the impact of a proposed change, so it cannot satisfy a requirement to revert on update failure.
- ✓
Rollback on failure
Why this is correct
The 'Rollback on failure' stack setting is the direct mechanism that causes CloudFormation to revert resources to the last successfully deployed state if an update operation fails. When enabled, CloudFormation automatically initiates a rollback by undoing any resource changes that occurred during the failed update, keeping the stack consistent with its previous known-good template. This setting is the only option listed that actively restores the prior stack state after an unsuccessful update.
- ✗
Stack policy
Why it's wrong here
A stack policy is an identity and access control document that governs which stack resources can be updated, protecting specific resources from intentional or accidental modification. It does not provide any failure recovery or rollback logic; in fact, a stack policy that denies updates can cause an update to fail, and it might even block rollback actions if it restricts the resources involved. Therefore, it is a preventative guardrail, not a mechanism for reverting to a previous state.
Go deeper
Related to this question
About these practice questions
Courseiva writes every SOA-C02 question from scratch — 1,169 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
JA
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.