Answer - C.
This is clearly mentioned in the AWS Documentation.
When creating an alarm, select a greater than or equal period to the frequency of the metric to be monitored.
For example, basic monitoring for Amazon EC2 provides metrics for your instances every 5 minutes.
When setting the alarm on a basic monitoring metric, select a period of at least 300 seconds (5 minutes)
Detailed monitoring for Amazon EC2 provides metrics for your instances every 1 minute.
When setting the alarm on a detailed monitoring metric, select a period of at least 60 seconds (1 minute).
If you set the alarm on a high-resolution metric, you can specify a high-resolution alarm with a period of 10 seconds or 30 seconds, or you can set a regular alarm with a period of any multiple of 60 seconds.
Option A is incorrect since the question does not mention anything on notifications.
Option B is incorrect since the standard resolution counters will not help define triggers within a 10 second interval.
Option D is incorrect since Cloudtrail is used for API Activity logging.
For more information on Cloudwatch metrics, please refer to the below Link-
https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/cloudwatch_concepts.html
To monitor application-specific events with a standard AWS service, we have several options available. In this case, we need to capture the number of logged-in users and trigger events accordingly. Also, during peak times, monitoring frequency will occur every 10 seconds.
Option A: Create an Amazon SNS notification Amazon Simple Notification Service (SNS) is a fully managed messaging service for both application-to-application (A2A) and application-to-person (A2P) communication. It can be used to send notifications via email, text, or push notification. However, SNS is not suitable for capturing and storing metrics.
Option B: Create a standard resolution custom Amazon CloudWatch log Amazon CloudWatch Logs is a fully managed service that makes it easy to collect, monitor, and analyze log files from EC2 instances, AWS CloudTrail, and other AWS services. CloudWatch Logs can capture and store any type of log data, including application logs. However, it is not designed to capture metrics and trigger events.
Option C: Create a high-resolution custom Amazon CloudWatch metric Amazon CloudWatch Metrics is a fully managed service that provides monitoring and observability for resources and applications on AWS. With CloudWatch Metrics, you can collect and store metrics, set alarms, and automatically react to changes in your AWS resources. CloudWatch Metrics provides a wide range of predefined metrics for AWS services and applications, and you can also create custom metrics based on your specific needs. CloudWatch Metrics can capture metrics at a resolution of up to one second, which is suitable for monitoring application-specific events every 10 seconds.
Option D: Create a custom Amazon CloudTrail log Amazon CloudTrail is a fully managed service that enables you to monitor, troubleshoot, and audit your AWS resources. CloudTrail provides event history of your AWS account activity, including actions taken through the AWS Management Console, AWS SDKs, command line tools, and other AWS services. However, CloudTrail is not designed to capture metrics and trigger events.
Therefore, the correct option to capture the number of logged-in users and trigger events accordingly, with monitoring frequency during peak times of every 10 seconds, is to create a high-resolution custom Amazon CloudWatch metric (Option C).
