Monitor Incoming Client Connections

Answer - B.

The AWS Documentation mentions the following.

Elastic Load Balancing provides access logs that capture detailed information about requests sent to your load balancer.

Each log contains information such as the time the request was received, the client's IP address, latencies, request paths, and server responses.

You can use these access logs to analyze traffic patterns and troubleshoot issues.

Option A is INCORRECT because CloudTrail captures all API calls for Elastic Load Balancing as events.

This is not the recommended approach to monitoring incoming connections to the ELB.Option B is CORRECT.

Each log contains information such as the time the request was received, the client's IP address, latencies, request paths, and server responses.

You can use these access logs to analyze traffic patterns and to troubleshoot issues.

Option C is invalid since the Logs agents are installed on EC2 Instances and not on the ELB.Option D is invalid since the metrics will not provide detailed information on the incoming connections.

For more information on Application Load balancer Logs, please refer to the below link-

https://docs.aws.amazon.com/elasticloadbalancing/latest/application/load-balancer-access-logs.html

Please refer to page 99 on the below link-

https://docs.aws.amazon.com/elasticloadbalancing/latest/application/elb-ag.pdf

The option that can suffice the requirement of monitoring incoming client connections to the Elastic Load Balancer (ELB) is to enable access logs on the load balancer. Therefore, the correct answer is B.

Explanation: The Elastic Load Balancer (ELB) is a highly scalable AWS service that distributes incoming traffic across multiple targets such as Amazon EC2 instances, containers, and IP addresses. The ELB can be used to achieve fault tolerance, high availability, and elasticity for your applications.

To monitor incoming client connections to the ELB, you can enable access logs on the load balancer. Access logs capture detailed information about each request that is received by the load balancer, including the time of the request, the client's IP address, the requested URL, the response code, and more.

By analyzing the access logs, you can gain insights into your application's performance, troubleshoot issues, and optimize your infrastructure. You can also use third-party tools such as Elasticsearch or Kibana to visualize and analyze the access logs.

The other options listed in the question are not suitable for monitoring incoming client connections to the ELB:

A. AWS CloudTrail is a service that records API calls made in your AWS account and delivers log files to an Amazon S3 bucket. CloudTrail is not directly related to monitoring client connections to an ELB.

C. CloudWatch Logs Agent is used to collect logs from Amazon EC2 instances and on-premises servers. It is not directly related to monitoring client connections to an ELB.

D. Creating a custom metric CloudWatch filter on your load balancer allows you to aggregate metrics based on specific criteria, but it is not directly related to monitoring client connections to an ELB.