A web application runs on an EC2 Auto Scaling group (ASG) behind an Application Load Balancer (ALB). The ASG spans three Availability Zones. After a deployment, new instances frequently fail the ALB target group health checks with HTTP 5xx responses and are quickly terminated by the ASG. What change most improves resiliency during deployments with minimal downtime by preventing premature removal of instances that are still starting?

Reduce the ASG health check grace period to 0 seconds so issues are detected faster.

A shorter grace period increases the chance that instances will be marked unhealthy before the application finishes startup or initialization. That can reduce available capacity and increase downtime during deployments.

Restrict the ASG to a single Availability Zone so health check evaluation is simpler.

Reducing the ASG to one Availability Zone decreases fault tolerance. It also increases the blast radius of deployment errors or AZ issues, worsening resiliency rather than improving it.

Disable ALB health checks so the ASG does not terminate instances on HTTP 5xx responses.

Disabling health checks removes the safety mechanism that prevents routing traffic to broken instances. The system can become unavailable or degrade because the ALB may route requests to unhealthy targets.

What does this SAA-C03 question test?

Authentication checks who the user is.

What is the correct answer to this question?

The correct answer is: Use a longer ASG health check grace period and deploy new instances using controlled replacement (for example, rolling instance refresh) so existing healthy instances continue serving while new ones warm up. — Best resilience comes from extending the ASG health check grace period to cover normal startup time and using controlled replacement, such as rolling instance refresh, so existing healthy instances remain in service while new ones warm up. This combination reduces the likelihood that newly launched instances are marked unhealthy before they are ready, while preserving capacity during deployment. Shortening grace periods or disabling health checks increases user impact; reducing the number of Availability Zones reduces overall resiliency. Option A can cause premature unhealthy marking, triggering ASG termination and reducing capacity during deployments. Option C removes multi-AZ redundancy, increasing the blast radius. Option D disables health-based traffic protection, risking routing to broken instances and reducing availability.

What should I do if I get this SAA-C03 question wrong?

Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.