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Zorluk: KolayAWS CloudFormation Stack and Drift Management

A SysOps Administrator initiates an update on an AWS CloudFormation stack. During the update, a resource creation fails. CloudFormation attempts to roll back the stack to its previous stable state, but the rollback process fails, leaving the stack in the UPDATE_ROLLBACK_FAILED state. Which of the following is a common cause for this rollback failure?

  1. A resource in the stack was manually deleted or modified outside of CloudFormation before the rollback was attempted.Cevap
  2. B
    The rollback was initiated automatically, but CloudFormation requires a manual rollback trigger to proceed from a failed update.
  3. C
    The update was performed using an in-place deployment strategy instead of a blue/green deployment strategy.
  4. D
    The user initiating the update lacks the iam:PassRole permission required to execute the rollback operation.

Cevap

A resource in the stack was manually deleted or modified outside of CloudFormation before the rollback was attempted.
The correct answer is that a resource in the stack was manually deleted or modified outside of CloudFormation before the rollback was attempted. When resources are modified or deleted out-of-band, the stack suffers from drift. During a rollback, CloudFormation attempts to return the resources to their previous configuration. If a resource no longer exists or is in an unexpected state, the rollback operation will fail, placing the stack in the UPDATE_ROLLBACK_FAILED state.

Adım Adım Çözüm

1
Analyze the stack status transitions.
The stack went from UPDATE_IN_PROGRESS to UPDATE_ROLLBACK_IN_PROGRESS and finally to UPDATE_ROLLBACK_FAILED.
Understanding the status flow helps pinpoint where the failure occurred.
2
Determine why CloudFormation would fail to revert a resource during a rollback.
If the resource state has drifted or if the resource was deleted manually outside of CloudFormation, CloudFormation's internal engine cannot reconcile the expected state.
Identifying the root cause of rollback failures is key to resolving stack update errors.

Anahtar Kavram

AWS CloudFormation Rollback Failures and Drift Management
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