Identifying EC2 Instances with Low Utilization Rates
Question
Your DevOps team has maintained a large number of EC2 instances in several AWS accounts.
There are some instances that were launched for testing purposes and are no longer used.
To save cost, you need to work out an approach to quickly identify the EC2 instances that have a low utilization rate, such as daily CPU utilization is 10% or less for several days.
Which method is the best that you should choose?
Answers
Explanations
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A. B. C. D.Correct Answer - D.
The question asks for the method that can quickly identify the EC2 instances with low utilization.
Therefore it should be avoided to perform configurations or checks for each instance repeatedly.
Option A is incorrect: Because it is not the best approach if compared with Option D as it has to configure every instance.
Option B is incorrect: Because the user has to create a new Lambda function, which is not the quickest way.
Option C is incorrect: Because the CPU usage data is already in CloudWatch Metrics.
So creating Filter in CloudWatch Logs is not essential.
Besides, each EC2 instance needs to install a CloudWatch Logs agent.
Option D is CORRECT: Because Trusted Advisor can efficiently identify those EC2 instances with low utilization, which is the best way to be chosen.
Check the below for its usage:
https://aws.amazon.com/premiumsupport/technology/trusted-advisor/best-practice-checklist/
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To identify the low utilization rate of EC2 instances, the best approach would be to use CloudWatch Metrics to create an alarm and trigger an SNS notification when CPU utilization is below 10% for several days.
Option A: In CloudWatch Metrics, for each instance, create an alarm and trigger an SNS notification when CPU utilization is below 10%.
This option is the most efficient and cost-effective way to identify low utilization rate of EC2 instances. By creating an alarm for each instance in CloudWatch Metrics, it will monitor the CPU utilization rate for each instance and trigger an SNS notification if the CPU utilization rate falls below 10% for several days. This will give the DevOps team the opportunity to either terminate the instance or take necessary actions to increase its utilization rate.
Option B: Create a Lambda function that checks the CPU utilization for each instance and triggers an SNS notification if the average CPU utilization rate is low.
This option involves creating a Lambda function that checks the CPU utilization rate for each instance and triggers an SNS notification if the average CPU utilization rate is low. Although this option can work, it requires more effort and resources to implement and maintain the Lambda function. Additionally, it may not be as effective as the first option because it only checks the average CPU utilization rate, whereas the first option checks for daily CPU utilization rate and triggers an alarm when it's below 10%.
Option C: In CloudWatch Logs, configure a Filter to check the usage rate of EC2 instances. Create an alarm if the utilization is low.
This option involves configuring a filter in CloudWatch Logs to check the usage rate of EC2 instances and creating an alarm if the utilization is low. Although this option can work, it is not as efficient and cost-effective as the first option because it requires more resources to configure and maintain the filter. Additionally, it may not be as effective as the first option because it checks for the usage rate, whereas the first option checks for CPU utilization rate.
Option D: In Trusted Advisor, check the status of Low Utilization Amazon EC2 Instances which is part of Cost Optimization Checks.
This option involves using Trusted Advisor to check the status of Low Utilization Amazon EC2 Instances. Although this option can work, it is not as effective as the first option because it only provides a general overview of low utilization instances and does not give detailed information about each instance. Additionally, it requires a subscription to Trusted Advisor, which is a paid service.
In conclusion, the best approach to quickly identify the EC2 instances that have a low utilization rate is to use CloudWatch Metrics to create an alarm and trigger an SNS notification when CPU utilization is below 10% for several days. This option is the most efficient and cost-effective way to identify low utilization instances.