Examkin

Question

Difficulty: MediumAWS CloudFormation Stack and Drift Management

An administrator is managing an AWS CloudFormation stack that contains an Amazon RDS DB instance. A stack update fails because of an invalid parameter value, and the stack enters the UPDATE_ROLLBACK_FAILED state. Upon inspecting the stack events, the administrator discovers that a dependency resource was manually deleted outside of CloudFormation during the update, preventing the DB instance from rolling back to its previous configuration. Which two actions should the administrator take to successfully return the stack to a working state and reconcile the resource configurations? (Select TWO.)

  1. Perform the Continue Update Rollback action and select the database resource to be skipped.Answer
  2. Manually update the actual resource configuration to match the expected template state after the rollback completes.Answer
  3. C
    Initiate a new stack update with the Force Rollback option enabled to ignore the deleted dependency.
  4. D
    Execute the Resolve Drift API command to automatically recreate the deleted dependency.
  5. E
    Add the iam:PassRole permission to the CloudFormation service role and immediately trigger a stack update.

Answer

Perform the Continue Update Rollback action, select the database resource to be skipped, and then manually update the actual resource configuration to match the expected template state after the rollback completes.
To resolve an UPDATE_ROLLBACK_FAILED state, the administrator must invoke the Continue Update Rollback action. By specifying the database resource to be skipped, CloudFormation can bypass the blocked resource and successfully roll back the rest of the stack. Once the stack reaches UPDATE_ROLLBACK_COMPLETE, the skipped resource must be manually updated to align with the template configuration.

Step-by-Step Solution

1
Identify the resource causing the rollback failure from the CloudFormation event logs.
The Amazon RDS DB instance is identified as the resource failing to roll back because its subnet/dependency was deleted.
Before resolving the rollback failure, the administrator must determine which resource is blocked.
2
Execute the Continue Update Rollback operation in the CloudFormation console or via the AWS CLI, specifying the blocked RDS resource to be skipped.
CloudFormation skips the rollback for the specified resource and successfully rolls back all other resources, transitioning the stack to the UPDATE_ROLLBACK_COMPLETE state.
Skipping the failing resource is the only way to move the stack out of the UPDATE_ROLLBACK_FAILED state without deleting the stack.
3
Manually recreate or update the skipped resource to match the template configuration, or update the template to match the resource's current state.
The resource and template configurations are reconciled, resolving the drift state.
Resources skipped during rollback remain out of sync with the CloudFormation template and must be reconciled manually.

Key Concept

Recovering from UPDATE_ROLLBACK_FAILED requires running ContinueUpdateRollback and optionally skipping the blocked resources. The skipped resources must then be reconciled manually to resolve any resulting drift.
Rate this question

Topics

AWS CloudFormation Stack and Drift Management

More questions from this topic