AWS Certified DevOps Engineer – Professional (DOP-C02) — Question 287

A DevOps team supports an application that runs in an Amazon Elastic Container Service (Amazon ECS) cluster behind an Application Load Balancer (ALB). Currently, the DevOps team uses AWS CodeDeploy to deploy the application by using a blue/green all-at-once strategy. Recently, the DevOps team had to roll back a deployment when a new version of the application dramatically increased response times for requests.

The DevOps team needs use to a deployment strategy that will allow the team to monitor a new version of the application before the team shifts all traffic to the new version. If a new version of the application increases response times, the deployment should be rolled back as quickly as possible.

Which combination of steps will meet these requirements? (Choose two.)

Answer options

• A. Modify the CodeDeploy deployment to use the CodeDeployDefault.ECSCanary10Percent5Minutes configuration.
• B. Modify the CodeDeploy deployment to use the CodeDeployDefault.ECSLinear10PercentEvery3Minutes configuration.
• C. Create an Amazon CloudWatch alarm to monitor the UnHealthyHostCount metric for the ALB. Set the alarm to activate if the metric is higher than the desired value. Associate the alarm with the CodeDeploy deployment group. Modify the deployment group to roll back when a deployment fails.
• D. Create an Amazon CloudWatch alarm to monitor the TargetResponseTime metric for the ALB. Set the alarm to activate if the metric is higher than the desired value. Associate the alarm with the CodeDeploy deployment group. Modify the deployment group to roll back when alarm thresholds are met.
• E. Create an Amazon CloudWatch alarm to monitor the TargetConnectionErrorCount metric for the ALB. Set the alarm to activate if the metric is higher than the desired value. Associate the alarm with the CodeDeploy deployment group. Modify the deployment group to roll back when alarm thresholds are met.

Correct answer: A, D

Explanation

Using the CodeDeployDefault.ECSCanary10Percent5Minutes deployment configuration allows the DevOps team to route a small portion (10%) of traffic to the new version for a 5-minute evaluation period before shifting the rest of the traffic. To automate the rollback specifically for latency issues, creating a CloudWatch alarm on the ALB's TargetResponseTime metric and associating it with the CodeDeploy deployment group ensures that any spike in response times immediately triggers an automatic rollback. Other options either use linear traffic shifting which takes longer to fully deploy, or monitor metrics that do not directly measure application response times.