Examkin

Question

Difficulty: EasyAuto Scaling and Elasticity

An Auto Scaling group is configured to scale out when CPU utilization exceeds 70%. During a traffic spike, a scale-out event is triggered. Arrange the operational steps in the correct chronological order from the initial metric alarm to the point where the new instance handles active client requests.

  1. 1The CloudWatch alarm breaches the threshold and triggers the Auto Scaling scale-out policy.
  2. 2The Auto Scaling group launches a new EC2 instance using the configuration defined in the active launch template.
  3. 3The newly launched EC2 instance is registered with the target group of the associated Application Load Balancer.
  4. 4The Application Load Balancer conducts health checks on the new instance and begins routing traffic to it once it becomes healthy.

Answer

The correct chronological sequence starts with the CloudWatch alarm triggering the scale-out policy. Next, the Auto Scaling group provisions the new instance using the active launch template. Then, the instance is registered with the target group of the Application Load Balancer. Finally, the load balancer routes client traffic to the instance once it passes health checks.
The correct order follows the logical operational flow: an alarm triggers the policy, the instance is provisioned, registered with the load balancer target group, and finally, traffic is routed to it after passing health checks.

Step-by-Step Solution

1
Triggering the policy
The CloudWatch alarm alerts the Auto Scaling group that CPU utilization has exceeded the threshold, starting the scale-out process.
Monitoring metrics must detect the load breach before any scaling action is initiated.
2
Provisioning the instance
Auto Scaling calls the EC2 API to boot up a new instance based on the launch template.
An active virtual machine must exist before it can be registered to receive network traffic.
3
Registering with the target group
The instance is registered with the load balancer target group in an initial state.
Registration is required so the load balancer is aware of the new resource's existence and IP address.
4
Passing health checks and serving traffic
The load balancer sends health probes to the instance, marks it healthy, and starts routing client requests.
Traffic routing must be delayed until the application on the instance is fully initialized and passing health checks to avoid routing requests to a broken node.

Key Concept

Auto Scaling instance launch and registration lifecycle with Elastic Load Balancing.
Rate this question

Topics

Auto Scaling and Elasticity

More questions from this topic