Examkin

Question

Difficulty: MediumAuto Scaling and Elastic Load Balancing (ELB)

An enterprise is migrating a legacy customer management API to AWS. The API runs on a cluster of Amazon EC2 instances in a private subnet, configured to listen on port 8080. An Application Load Balancer (ALB) is deployed in public subnets to distribute incoming traffic. The application needs to dynamically scale based on demand while maintaining high availability. Traffic to the backend instances must be securely restricted, and the load balancer must accurately determine target health. Which two configurations should the solutions architect implement to satisfy these requirements? (Select two.)

  1. Configure the target group to route traffic to port 8080 and set the health check port to use the traffic port.Answer
  2. Configure the security group of the EC2 instances to allow inbound traffic on port 8080 from the security group of the Application Load Balancer.Answer
  3. C
    Configure the target group health check to query the default port 80 to ensure the web server is listening, while routing main traffic to port 8080.
  4. D
    Create a Network ACL on the private subnet that allows inbound traffic on port 8080 from the security group of the Application Load Balancer.
  5. E
    Configure an Amazon Route 53 latency-based routing policy to direct client requests directly to the private EC2 instances to handle the scaling load.

Answer

To support an application running on port 8080, the target group must route traffic to port 8080 with the health check port matching the traffic port, and the EC2 instances' security group must allow inbound traffic on port 8080 from the security group of the Application Load Balancer.
To support an application running on port 8080, the target group must route traffic to port 8080 and its health checks must target the same port (or 'traffic-port') to ensure accurate status reporting. Additionally, to secure the architecture, the EC2 instances' security group should allow inbound traffic on port 8080 specifically from the security group of the Application Load Balancer.

Step-by-Step Solution

1
Configure the ELB Target Group mapping.
The target group is set to route requests to backend instances on port 8080.
Since the legacy API is configured to listen on port 8080, the ALB needs to target that specific port.
2
Align target health check port configuration.
The target group health checks query port 8080 (the traffic port).
Matching the health check port to the traffic port ensures that the load balancer correctly detects application availability without causing false unhealthy states.
3
Configure instance security group rules.
The EC2 instances' security group is restricted to allow port 8080 traffic only from the ALB's security group.
This implements the principle of least privilege by securing the backend instances so they can only receive traffic originating from the load balancer.

Key Concept

Integrating Elastic Load Balancing (ELB) with backend EC2 targets requires matching application ports for routing and health checks, and establishing secure path communications via security group chaining.
Estimated Time:2m 0s
Rate this question

Topics

Auto Scaling and Elastic Load Balancing (ELB)

More questions from this topic