A SysOps administrator has configured an Application Load Balancer (ALB) to route HTTP traffic to a fleet of Amazon EC2 instances. After deployment, all instances in the target group are reported as unhealthy with the status code 'HealthCheck.Failed'. The web application is configured to serve content on port 80.
Which two configurations should the administrator inspect to resolve the failing health checks? (Select TWO.)
- The security group associated with the EC2 instances to ensure it allows inbound traffic on port 80 from the ALB security group.Answer
- The health check path in the target group settings to ensure it points to a valid file that returns a 200 OK status.Answer
- CThe Route 53 routing policy to ensure that active-passive failover is correctly configured to route traffic to the primary ALB.
- DThe target group configuration to verify that the health check port is set to 443 to force secure connections.
- EThe EC2 instance configuration to verify that detailed monitoring is enabled to reduce the health check interval.
Answer
The correct configurations to verify are the security group associated with the EC2 instances to ensure it allows inbound traffic on port 80 from the ALB security group, and the health check path in the target group settings to ensure it points to a valid file that returns a 200 OK status.
For an Application Load Balancer health check to pass, the load balancer must be able to complete a TCP handshake and receive a successful HTTP response. Verifying the EC2 security group ensures the network path is open from the load balancer, and verifying the health check path ensures the application returns the expected success code (such as 200 OK).
Step-by-Step Solution
Key Concept
Successful load balancer health checks require both network-level access (via security groups and network ACLs) and application-level response (via valid HTTP endpoints returning successful status codes).