An organization hosts a legacy payroll application on Amazon EC2 instances managed by an Auto Scaling group (ASG) behind an Application Load Balancer (ALB). The payroll application runs on port 8088. The target group is configured to route HTTP traffic to the EC2 instances on port 8088. The EC2 instances are in a security group that allows inbound traffic on port 8088 from the ALB's security group. However, the ALB marks all registered EC2 instances as unhealthy. A solutions architect discovers that the target group's health checks are configured to use HTTP on port 80. How should the solutions architect resolve this issue and restore the system to a healthy state?
- AConfigure the target group's health check port to use port 80 to match standard HTTP configurations.
- BAdd an inbound rule to the EC2 instances' security group to allow return traffic on ephemeral ports from the ALB, as security groups are stateless.
- Modify the target group's health check settings to use port 8088 or set the health check port to traffic-port.Answer
- DConfigure an Amazon Route 53 latency routing policy to route traffic directly to the EC2 instances instead of the ALB to bypass the target group health checks.
Answer
Modify the target group's health check settings to use port 8088 or set the health check port to traffic-port.
The correct option is to modify the target group's health check settings to use port 8088 or 'traffic-port'. By default, the ALB target group health check uses the port configured for traffic routing ('traffic-port') unless overridden. If it was overridden to port 80, the health check requests will be sent to port 80 on the EC2 instances. Since the payroll application is listening on port 8088 and no service is listening on port 80, the health checks will fail. Correcting the health check port resolves this mismatch.
Step-by-Step Solution
Key Concept
ELB Target Group Health Check Port Configuration
Estimated Time:1m 30s