Lessons

Setting Up SNS Notifications for CloudWatch Alarms

Introduction

In this lesson, we will learn how to set up SNS notifications for CloudWatch alarms. SNS (Simple Notification Service) is a fully managed messaging service provided by AWS that makes it easy to set up, operate, and send notifications from the cloud. CloudWatch is a monitoring and observability service provided by AWS that allows you to collect and track metrics, monitor log files, set alarms, and automatically react to changes in your AWS resources. By setting up SNS notifications for CloudWatch alarms, you can receive alerts when certain thresholds are breached, allowing you to take timely action to address any issues.

Prerequisites

Before we begin, make sure you have the following prerequisites:

  • An AWS account
  • AWS CLI installed and configured
  • Node.js and npm installed
  • Basic knowledge of AWS CDK and Typescript

Setting Up SNS Topic

The first step in setting up SNS notifications for CloudWatch alarms is to create an SNS topic. An SNS topic is a communication channel that allows you to send messages and notifications to subscribed endpoints. To create an SNS topic, you can use the AWS CDK with Typescript. Here’s an example code snippet to create an SNS topic:

import * as sns from '@aws-cdk/aws-sns';
import * as cdk from '@aws-cdk/core';

export class SnsTopicStack extends cdk.Stack {
  constructor(scope: cdk.Construct, id: string, props?: cdk.StackProps) {
    super(scope, id, props);

    const topic = new sns.Topic(this, 'MySnsTopic', {
      displayName: 'My SNS Topic',
    });
  }
}

In this code snippet, we import the necessary modules from the AWS CDK library and create an SNS topic with the display name ‘My SNS Topic’. Make sure to deploy this stack using the AWS CDK CLI after defining the stack in your project.

Creating CloudWatch Alarm

Next, we need to create a CloudWatch alarm that will trigger when a certain threshold is breached. You can create a CloudWatch alarm using the AWS CLI. Here’s an example command to create a CloudWatch alarm that monitors the CPU utilization of an EC2 instance:

aws cloudwatch put-metric-alarm --alarm-name "CPUUtilizationAlarm" --alarm-description "Alarm when CPU utilization exceeds 70%" --metric-name "CPUUtilization" --namespace "AWS/EC2" --statistic "Average" --period 300 --threshold 70 --comparison-operator "GreaterThanThreshold" --dimensions Name=InstanceId,Value=i-1234567890abcdef0 --evaluation-periods 1 --alarm-actions arn:aws:sns:us-east-1:123456789012:MySnsTopic

In this command, we use the put-metric-alarm API to create a CloudWatch alarm that monitors the CPU utilization metric of an EC2 instance. We set the threshold to 70% and specify the SNS topic ARN to receive notifications when the alarm is triggered.

Subscribing to SNS Topic

Once the SNS topic and CloudWatch alarm are set up, you need to subscribe to the SNS topic to receive notifications. You can subscribe to an SNS topic using the AWS CLI. Here’s an example command to subscribe an email address to the SNS topic:

aws sns subscribe --topic-arn arn:aws:sns:us-east-1:123456789012:MySnsTopic --protocol email --notification-endpoint example@example.com

In this command, we use the subscribe API to subscribe an email address to the SNS topic with the ARN arn:aws:sns:us-east-1:123456789012:MySnsTopic. Once subscribed, the email address will receive notifications when the SNS topic publishes messages.

Testing the Setup

To test the setup, you can manually trigger the CloudWatch alarm by simulating a high CPU utilization on the EC2 instance. Once the alarm is triggered, you should receive a notification via email from the SNS topic.

Conclusion

In this lesson, we learned how to set up SNS notifications for CloudWatch alarms using practical examples with AWS CDK and Typescript. By following the steps outlined in this lesson, you can effectively monitor your AWS resources and receive timely alerts when thresholds are breached. Key learnings from this lesson include creating an SNS topic, setting up a CloudWatch alarm, subscribing to the SNS topic, and testing the setup to ensure notifications are received successfully.

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