ELB Performance Monitoring and Notification

Correct Answer - A and C.

When you use CloudWatch metrics for an ELB, you can get some read requests and latency out of the box.

For more information on using CloudWatch with the ELB, please visit the following URL-

https://docs.aws.amazon.com/elasticloadbalancing/latest/classic/elb-cloudwatch-metrics.html

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

Each log contains information on when 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.

For more information on using ELB logs, please visit the following URL-

https://docs.aws.amazon.com/elasticloadbalancing/latest/classic/access-log-collection.html

Option B is INCORRECT because using VPC flow logs, we cannot pinpoint the issues related to ELB performance.

Option D is INCORRECT because CloudTrail is used only for monitoring API activities on AWS resources.

From the given requirements, there are two aspects that need to be addressed: collecting and analyzing logs about ELB's performance, and sending notifications when latency exceeds 10 seconds. Two options need to be selected to address these requirements.

Option A: Use CloudWatch for monitoring.

CloudWatch is a monitoring and management service offered by AWS that enables users to collect and track metrics, collect and monitor log files, and set alarms. CloudWatch can be used to monitor the performance of AWS resources, including EC2 instances and ELBs.

To collect and analyze logs about ELB's performance, CloudWatch can be used to collect ELB access logs. These logs contain information about each request that is sent to the ELB, including the time taken to process the request. CloudWatch can also be used to monitor the latency of the ELB, which is the time taken to process a request from the client to the back-end instances. Using CloudWatch, users can set up alarms that notify them when the latency exceeds a certain threshold, such as 10 seconds, as required by the scenario.

Therefore, Option A is a suitable option for addressing both of the given requirements.

Option C: Enable the logs on the ELB with Latency Alarm that sends an email and then investigate the logs whenever there is an issue.

This option suggests enabling ELB logs and setting up a latency alarm to notify administrators via email when the latency exceeds 10 seconds. While this option could work, it is not as efficient as using CloudWatch, as it requires manual investigation of logs whenever there is an issue. Additionally, the logs generated by ELB may not provide as much detail as the logs collected by CloudWatch.

Option B: Enable VPC Flow logs and then investigate the logs whenever there is an issue.

VPC Flow Logs are a feature of Amazon VPC that captures information about the IP traffic going to and from network interfaces in a VPC. While this option could provide visibility into the network traffic between the ELB and the EC2 instances, it is not directly related to the ELB's performance or latency. Moreover, it does not address the need to set up alarms when the latency exceeds 10 seconds.

Option D: Use CloudTrail to monitor whatever metrics need to be monitored.

CloudTrail is a service that provides event history of AWS account activity. It records account activity made by users, services, or applications within an AWS account. While CloudTrail can provide visibility into AWS account activity, it is not suitable for monitoring the performance or latency of an ELB.

Therefore, options A and C are the most suitable options for addressing the requirements given in the scenario.