DOP-C02 Incident and Event Response Practice Question
A company uses AWS CloudFormation to deploy infrastructure. A stack update fails with the error 'UPDATE_ROLLBACK_FAILED'. What should the engineer do to resolve this?
⚠ Common exam trap
The trap is thinking a failed rollback can be fixed by simply retrying or deleting the stack, when the correct action is the ContinueUpdateRollback recovery operation.
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
✓
Use the 'ContinueUpdateRollback' operation to fix the resource that caused the failure.
When a CloudFormation stack update fails and rollback also fails, the stack enters UPDATE_ROLLBACK_FAILED, a terminal state where CloudFormation cannot automatically recover. The ContinueUpdateRollback API operation tells CloudFormation to resume rolling back the stack, optionally skipping specific resources that are stuck, so the engineer can manually fix the problematic resource and then complete the rollback. This is the documented recovery path for this state.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Retry the stack update with the same parameters.
Why it's wrong here
Retrying the stack update with identical parameters is ineffective because the underlying cause of the failure—such as an invalid resource property, insufficient IAM permissions, or a conflicting external dependency—remains unchanged. Furthermore, if the stack is in the UPDATE_ROLLBACK_FAILED state, CloudFormation blocks additional update operations until the rollback is successfully completed, so the retry may be rejected outright instead of executing.
- ✗
Delete the stack and recreate it.
Why it's wrong here
Deleting and recreating the stack is a destructive action that can cause permanent data loss for any resources that were successfully provisioned or updated before the failure, such as databases, EC2 volumes, or S3 bucket contents. It also discards any existing infrastructure state and manual dependencies that are not defined in the template, forcing a full cold-start rebuild. The recovery path should aim to restore the existing stack's previous stable state, not destroy it.
- ✗
Ignore the error and continue using the stack.
Why it's wrong here
Ignoring the error leaves the stack in a failed operational state, typically UPDATE_ROLLBACK_FAILED or UPDATE_ROLLBACK_IN_PROGRESS, which means CloudFormation cannot apply further changes and resources may be left in a partially configured, inconsistent condition. This state can cause drift, interfere with dependent stacks, and block any future update or delete operations, making the infrastructure effectively unmanageable until the rollback is resolved.
- ✓
Use the 'ContinueUpdateRollback' operation to fix the resource that caused the failure.
Why this is correct
The ContinueUpdateRollback operation is the correct recovery mechanism specifically designed for stacks that fail during an update and subsequently fail to roll back automatically, landing in UPDATE_ROLLBACK_FAILED. It instructs CloudFormation to resume the rollback to the last known good state, optionally skipping resources that are causing repeated failures via the ResourcesToSkip parameter after manually fixing them. This restores the stack to a stable, updatable condition without destroying the underlying infrastructure.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Amazon Web Services exam blueprint
This DOP-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 DOP-C02 exam.