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PASSEDcloud / cloudformation_stack_rollback
CloudFormation Stack Rollback — Production Update Failed
A CloudFormation stack update to production fails during resource creation, triggering an automatic rollback that itself gets stuck in UPDATE_ROLLBACK_FAILED state due to a manually modified resource outside of CloudFormation control.
Pattern
AWS_CLOUD
Severity
CRITICAL
Confidence
95%
Remediation
Remote Hands
Test Results
| Metric | Expected | Actual | Result |
|---|---|---|---|
| Pattern Recognition | AWS_CLOUD | AWS_CLOUD | |
| Severity Assessment | CRITICAL | CRITICAL | |
| Incident Correlation | Yes | 22 linked | |
| Cascade Escalation | N/A | No | |
| Remediation | — | Remote Hands — Corax contacts on-site support via call, email, or API |
Scenario Conditions
Production CloudFormation stack with 47 resources. Stack update adds new RDS instance. Manual security group modification outside CF. Rollback gets stuck. Stack in UPDATE_ROLLBACK_FAILED state.
Injected Error Messages (2)
aws cloudformation stack 'prod-main' entered UPDATE_ROLLBACK_FAILED state — initial update failed creating rds instance subnet group due to insufficient IP addresses in subnet, automatic rollback attempted but failed on resource 'ProdSecurityGroup' which was manually modified outside cloudformation, stack is now in an unrecoverable state requiring manual intervention via continue-update-rollback with resources-to-skip, 47 production resources at risk
production API returning errors during aws cloudformation rollback — backend services experiencing configuration drift, new resources partially created then abandoned, routing rules inconsistent between old and new configuration, manual remediation required to restore production stability
Neural Engine Root Cause Analysis
The CloudFormation stack 'prod-main' failed during an update operation due to insufficient IP addresses in a subnet when creating an RDS instance subnet group. The automatic rollback mechanism then failed because the 'ProdSecurityGroup' resource was manually modified outside of CloudFormation, creating a drift condition. The stack is now in UPDATE_ROLLBACK_FAILED state, which is an unrecoverable condition that requires manual intervention to resolve resource drift and continue the rollback process.
Remediation Plan
1. Identify the manually modified 'ProdSecurityGroup' resource and document changes made outside CloudFormation. 2. Use AWS CLI command 'aws cloudformation continue-update-rollback --stack-name prod-main --resources-to-skip ProdSecurityGroup' to skip the problematic resource and complete rollback. 3. Address the underlying IP address shortage by expanding subnet CIDR blocks or creating additional subnets. 4. Recreate or import the ProdSecurityGroup back into CloudFormation management to eliminate drift. 5. Retry the original stack update with proper subnet capacity. 6. Implement CloudFormation drift detection and prevention policies to avoid future manual modifications.
Tested: 2026-03-30Monitors: 2 | Incidents: 2Test ID: cmnckbwur08brobqe4r4wxxiu