How to Create a CloudWatch Alarm for RDS CPU Utilization
A SysOps administrator needs to monitor the CPU utilization of an Amazon RDS for PostgreSQL instance and receive an alert if the usage exceeds 80% for 5 consecutive minutes. The database is in a production environment. What is the MOST efficient way to achieve this?
Quick Answer
The answer is to create an Amazon CloudWatch alarm on the RDS CPUUtilization metric with a threshold of 80 and an evaluation period of 5 minutes. This is correct because CloudWatch natively publishes the CPUUtilization metric for every RDS instance at one-minute intervals when standard monitoring is enabled, allowing you to set up a CloudWatch alarm for RDS CPU utilization that directly checks for five consecutive data points exceeding 80% without any custom scripts or additional infrastructure. On the AWS Certified SysOps Administrator Associate SOA-C02 exam, this scenario tests your understanding of native CloudWatch-RDS integration versus more complex solutions like Lambda or EC2-based monitoring—a common trap is overcomplicating the answer by adding unnecessary steps. Remember that for RDS, the CPUUtilization metric is always available by default, so the most efficient path is always a simple CloudWatch alarm. Memory tip: "Five minutes, one metric, no gimmicks" — keep it native.
⚠ Common exam trap
The trap here is that candidates may overcomplicate the solution by assuming CloudWatch cannot natively monitor RDS CPU utilization or that custom code is required, when in fact RDS automatically publishes CPUUtilization to CloudWatch and alarms can be configured directly.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Create an Amazon CloudWatch alarm on the CPUUtilization metric with a threshold of 80 and an evaluation period of 5 minutes.
Amazon CloudWatch natively publishes the CPUUtilization metric for RDS instances every minute (standard monitoring) or every 5 minutes (enhanced monitoring). Creating a CloudWatch alarm with a threshold of 80% and an evaluation period of 5 consecutive minutes directly meets the requirement without additional infrastructure. This is the most efficient approach as it uses built-in RDS monitoring capabilities with no custom code or third-party tools.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Configure an Amazon Simple Notification Service (SNS) topic to subscribe to CloudWatch alarms for all RDS metrics and filter for CPUUtilization.
Why it's wrong here
SNS is a notification delivery channel, not a monitoring or alarm configuration tool.
- ✗
Create an AWS Lambda function that queries the RDS performance schema every minute and publishes a custom metric to CloudWatch, then set an alarm.
Why it's wrong here
This is overly complex; RDS CPUUtilization is already available as a standard CloudWatch metric.
- ✓
Create an Amazon CloudWatch alarm on the CPUUtilization metric with a threshold of 80 and an evaluation period of 5 minutes.
Why this is correct
CloudWatch directly monitors RDS metrics and can trigger an alarm based on the metric's value over a specified period.
- ✗
Use a third-party monitoring tool such as Datadog because CloudWatch cannot monitor RDS CPU utilization.
Why it's wrong here
CloudWatch natively monitors RDS CPU utilization; third-party tools are not the most efficient.
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Same concept, more angles
2 more ways this is tested on SOA-C02
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A SysOps administrator needs to monitor the CPU utilization of an Amazon RDS for MySQL DB instance. The administrator wants to receive a notification when the average CPU utilization exceeds 80% for 10 consecutive minutes. Which steps should the administrator take to set up this monitoring?
easy- A.Use CloudWatch Logs to monitor the database logs and create an alarm based on log patterns.
- B.Enable Enhanced Monitoring and create an alarm on the 'CPUUtilization' metric in RDS console.
- ✓ C.Create a CloudWatch alarm on the 'CPUUtilization' metric with a threshold of 80% and an SNS topic for notifications.
- D.Enable CloudTrail and create a metric filter for CPU utilization.
Why C: Amazon RDS automatically publishes the 'CPUUtilization' metric to CloudWatch, and a CloudWatch alarm can be configured with a threshold of 80% for the 'Average' statistic over a period of 10 consecutive minutes (e.g., 10 evaluation periods of 1 minute each). The alarm can then trigger an SNS topic to send notifications when the threshold is breached. This directly meets the requirement without additional services.
Variation 2. A SysOps administrator needs to monitor the CPU utilization of an Amazon RDS DB instance and receive an alarm when CPU utilization exceeds 80% for 5 consecutive minutes. Which AWS service should be used to create this alarm?
easy- A.AWS CloudTrail
- ✓ B.Amazon CloudWatch
- C.AWS Config
- D.AWS Trusted Advisor
Why B: Amazon CloudWatch is the native AWS monitoring service that can track RDS DB instance metrics, such as CPU utilization, and trigger alarms based on thresholds and time periods. In this scenario, you would create a CloudWatch alarm on the `CPUUtilization` metric for the specific DB instance, with a threshold of 80% and a period of 5 consecutive minutes (e.g., 5 datapoints of 1-minute periods).
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This SOA-C02 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the SOA-C02 exam.