Question

An Elastic Load Balancer has marked all the EC2 instances in the target group as unhealthy. Surprisingly, when a developer enters the IP address of the EC2 instances in the web browser, he can access the website. What could be the reason the instances are being marked as unhealthy? (Select two)

a) Incorrect security group rules
b) Target group health check misconfiguration
c) Issues with the EC2 instance operating system
d) Elastic Load Balancer is not properly configured

Answer 1

An Elastic Load Balancer may consider EC2 instances unhealthy due to incorrect security group rules or a misconfiguration of the target group health checks.

Step-by-step explanation:

If an Elastic Load Balancer has marked all the EC2 instances in the target group as unhealthy, but the instances are still accessible via their IP addresses, there are two potential reasons.

First, the security group rules might be incorrectly set up, which can block the health check traffic from the load balancer to the EC2 instances.

Second, there may be a misconfiguration in the target group health checks, such as incorrect response timeouts, unhealthy thresholds, or the health check path in the target group settings does not match the application configuration.