CodeDeploy Automatic Rollback — Configuration Steps
A company is using AWS CodeDeploy to deploy an application to an Auto Scaling group. The deployment is failing because the new instances are not passing the health checks. The team wants to automatically roll back the deployment if health checks fail. Which THREE steps should the team take?
Quick Answer
The answer is to configure the Auto Scaling group to use an ELB health check with a sufficient grace period, set up CloudWatch alarms on the failed health check metric, and enable automatic rollback in the CodeDeploy deployment group. This combination works because the ELB health check determines instance readiness, the grace period prevents premature termination during startup, and the CloudWatch alarm triggers the rollback when the health check failure threshold is breached, while the CodeDeploy rollback setting ensures the previous revision is redeployed. On the AWS Certified DevOps Engineer Professional DOP-C02 exam, this scenario tests your understanding of how CodeDeploy’s automatic rollback integrates with Auto Scaling lifecycle hooks and ELB health checks—a common trap is confusing deployment group alarms with instance-level alarms, or forgetting that the grace period must be long enough to avoid false positives. A useful memory tip is “Alarm, Grace, Rollback”: the alarm detects failure, the grace period buys time, and the rollback restores stability.
⚠ Common exam trap
A common mix-up: candidates think that simply enabling automatic rollback on deployment failure (Option C) is sufficient, but they miss that you must also configure a CloudWatch alarm (Option B) to detect health check failures that occur after the deployment completes, because a deployment can succeed initially but then fail health checks later.
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
✓
Create a CloudWatch alarm based on the ELB health check metric.
Creating a CloudWatch alarm based on the ELB health check metric allows you to monitor the health of instances in the Auto Scaling group. When the alarm triggers due to failed health checks, it can be used in conjunction with an automatic rollback configuration to revert the deployment to the previous revision. This ensures that unhealthy instances are detected early and the deployment is rolled back automatically, minimizing downtime.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Use a deployment configuration with a high minimum healthy host percentage.
Why it's wrong here
Incorrect: Not directly for rollback.
- ✓
Create a CloudWatch alarm based on the ELB health check metric.
Why this is correct
Correct: Alarm can trigger rollback.
- ✓
Configure the deployment group to automatically roll back when a deployment fails.
Why this is correct
Correct: Enables automatic rollback on failure.
- ✓
Configure the Auto Scaling group to use an ELB health check with a sufficient grace period.
Why this is correct
Correct: Ensures health check is properly configured.
- ✗
Store the deployment artifacts in an S3 bucket with versioning enabled.
Why it's wrong here
Incorrect: Not related to rollback.
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Same concept, more angles
1 more way this is tested on DOP-C02
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A company uses AWS CodeDeploy to deploy a web application to an Auto Scaling group. After a deployment, some instances fail the health check and are terminated by the Auto Scaling group. What should the DevOps engineer do to prevent this?
hard- A.Configure a CloudWatch alarm to stop the deployment if instances are unhealthy.
- B.Modify the deployment configuration to deploy to only one instance at a time.
- ✓ C.Update the deployment group to use an Elastic Load Balancer and configure health checks.
- D.Increase the desired capacity of the Auto Scaling group to tolerate failures.
Why C: Configuring an Elastic Load Balancer (ELB) with health checks in the CodeDeploy deployment group allows CodeDeploy to monitor instance health during deployment. If an instance fails the ELB health check, CodeDeploy can automatically roll back or stop the deployment, preventing the Auto Scaling group from terminating unhealthy instances. This integrates the deployment lifecycle with load balancer health signals, ensuring only healthy instances serve traffic.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.