A large group-buying website is deployed in AWS using a classic Load Balancer and an Auto Scaling Group. The ELB is configured with the below health check:

Answer options:

A.Increase the Timeout to 25 seconds.
B.Increase the Healthy threshold to 5.
C.Decrease the Unhealthy threshold to 2.
D.Increase the Interval to 35 seconds.
E.Modify Ping target to use HTTP instead of HTTPS.

Correct Answer – A, D
Check https://docs.aws.amazon.com/elasticloadbalancing/latest/classic/elb-healthchecks.html for the configurations of Health Checks for Classic Load Balancer. Health Check parameters can be easily adjusted in the AWS console:
Option A is CORRECT: Because in this case, we should provide more time for the EC2 instance to pass the health check. Timeout controls the timer for ELB to check the configured Ping Target. Increasing the timer can help the EC2 instance to react to the ELB health check successfully.
Option B is incorrect: Because Healthy threshold is the number of consecutive successful health checks before declaring an EC2 instance healthy. If the number is increased, it will be slower for instance to pass all the health check tests.
Option C is incorrect: Because the Unhealthy threshold is the number of consecutive failed health checks before declaring an EC2 instance unhealthy. In this case, newly launched instances are already unhealthy which is the initial status. Therefore, adjusting this parameter will not help solve the problem.
Option Dis CORRECT: Similar to
Option A. This option allows more time for the instance to pass the health check. Interval is the amount of time between health checks.
Option E is incorrect: Because modifying protocol does not help pass the health check. Besides, this approach may bring in security issues.