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Difficulty: EasyAuto Scaling and Elastic Load Balancing (ELB)

A company is hosting a simple web application on Amazon EC2 instances. The instances are managed by an Auto Scaling group (ASG) and receive traffic through an Application Load Balancer (ALB). The web application is configured to run on custom port 80808080. The solutions architect needs to configure the load balancer and security groups to ensure traffic is correctly routed and instances are properly monitored.

Which of the following actions should the solutions architect perform to meet these requirements? (Select two.)

  1. Configure the target group of the Application Load Balancer to perform health checks on the custom port 80808080.Answer
  2. Configure the security group of the EC2 instances to allow inbound traffic from the security group of the Application Load Balancer on port 80808080.Answer
  3. C
    Configure the target group to perform health checks on default port 8080, while keeping the application listener on port 80808080.
  4. D
    Configure a stateless Network ACL on the subnet to allow inbound traffic on port 80808080, relying on the stateful security group to automatically permit return traffic without additional outbound rules.
  5. E
    Configure an Amazon Route 53 Latency routing policy pointing to individual EC2 instances to dynamically handle load balancing and instance failover.

Answer

Configure the target group of the Application Load Balancer to perform health checks on the custom port 80808080, and configure the security group of the EC2 instances to allow inbound traffic from the security group of the Application Load Balancer on port 80808080.
To ensure that the Application Load Balancer (ALB) can successfully route traffic and monitor the health of the EC2 instances, the target group health checks must query the port where the application is listening (port 80808080). Additionally, the security group attached to the EC2 instances must allow inbound traffic on port 80808080 from the security group of the ALB.

Step-by-Step Solution

1
Identify the application port configuration.
The application listens on custom port 80808080.
All traffic from the load balancer and health checks must be routed to this specific port.
2
Set the health check port for the ELB Target Group.
The Target Group is configured to run active health checks on port 80808080.
If default port 8080 is used, health check probes will fail because no service is listening on port 8080, causing the ALB to flag all instances as unhealthy.
3
Configure instance-level security groups to accept traffic.
The EC2 instances' security group is updated to allow inbound TCP traffic on port 80808080 from the ALB's security group source.
This allows the ALB to forward client requests and perform health check probes successfully.

Key Concept

ELB Target Group health check configurations and security group port alignment for custom application ports.
Estimated Time:1m 0s
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Topics

Auto Scaling and Elastic Load Balancing (ELB)

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