Monitoring and Health Checks for Classic Load Balancer and Auto Scaling Group

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.

To determine which health check parameter to adjust, we need to understand the purpose and behavior of each parameter:

• Timeout: The amount of time the load balancer waits for a response from the target before considering it a failed health check. If the target is taking too long to respond, increasing the timeout can help prevent false positives.
• Interval: The amount of time between health checks. If the interval is too short, targets may be overloaded with health checks. If the interval is too long, failures may go undetected.
• Healthy threshold: The number of consecutive successful health checks required before a target is considered healthy. Increasing this can help prevent false positives.
• Unhealthy threshold: The number of consecutive failed health checks required before a target is considered unhealthy. Decreasing this can help detect failures faster.
• Ping target: The protocol, port, and path used to check the target's health. Switching to HTTP from HTTPS can reduce the load on the target.

In this scenario, the website is experiencing health check failures with a classic Load Balancer and an Auto Scaling Group. Therefore, the most likely solution is to adjust one of the health check parameters to improve the detection of failures.

Option A: Increasing the Timeout to 25 seconds might help prevent false positives by allowing more time for targets to respond. However, it may also delay the detection of real failures.

Option B: Increasing the Healthy threshold to 5 can reduce false positives but may also delay the detection of real failures.

Option C: Decreasing the Unhealthy threshold to 2 can help detect failures faster, but it may also increase the risk of false positives.

Option D: Increasing the Interval to 35 seconds can reduce the load on targets but may also delay the detection of real failures.

Option E: Modifying the Ping target to use HTTP instead of HTTPS can reduce the load on targets and may help detect failures faster.

Based on the above analysis, Option E seems like the best solution as it can reduce the load on targets and may help detect failures faster. However, the best solution may depend on the specific nature of the failures and the workload of the targets. It is important to monitor the effects of any changes to health check parameters to ensure they are effective and do not cause new issues.