Day 47 — Amazon CloudWatch: Monitoring, Events, Logs, and Alerts

Today I learned about Amazon CloudWatch, one of the most powerful monitoring tools in AWS. It helps keep an eye on application performance, logs, infrastructure health, and more — all in real-time.

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👀 What is Amazon CloudWatch?

Amazon CloudWatch is a monitoring and observability service built for DevOps engineers, developers, site reliability engineers (SREs), and IT managers.

It provides data and actionable insights to monitor your applications, understand system-wide performance changes, and optimize resource utilization.

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📊 CloudWatch Metrics

CloudWatch collects and tracks metrics — data points for AWS services and resources, such as:

• EC2 instances (CPU, disk I/O, network usage)

• EBS volumes (read/write operations)

• Elastic Load Balancers (healthy/unhealthy host counts)

• RDS databases, S3 buckets, CloudFront, Lambda, and more

• You can also push custom metrics from your own apps/scripts

📌 These metrics are visualized in CloudWatch Dashboards.

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🚨 CloudWatch Alarms

You can create Alarms to monitor metrics and automatically take actions like:

• Send notifications via SNS (Simple Notification Service)

• Auto-scale EC2 instances up or down

• Reboot or stop an instance

🔔 Example:

If an EC2 instance’s CPU usage is over 80% for 5 minutes, trigger an alarm and send an alert via SNS.

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🔁 CloudWatch Events (Now part of EventBridge)

CloudWatch Events deliver real-time system notifications when AWS resources change state.

You can:

• Trigger Lambda functions, SNS, or Step Functions when events occur

• Track instance state changes, code deployments, health checks, etc.

Example:

Automatically stop an EC2 instance every day at 7 PM using a scheduled rule

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📝 CloudWatch Logs

You can stream and store logs from services like:

• EC2 (via CloudWatch Agent)

• AWS CloudTrail

• Lambda logs

• Route53 DNS logs

• Custom applications (via log drivers)

Logs are searchable and retainable. You can also create metric filters from logs to trigger alarms.

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🔔 What is Amazon SNS?

Amazon SNS (Simple Notification Service) is a fully managed pub/sub messaging service.

• Used to send alerts, status updates, or event-based notifications

• Supports email, SMS, Lambda, HTTP endpoints, etc.

• Works hand-in-hand with CloudWatch Alarms to deliver updates

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🧠 What I Learned Today

• CloudWatch helps track metrics, logs, and system events in near real-time

• Alarms are essential for automating responses to thresholds

• Logs and events give deep insights into system health

• SNS integrates perfectly for alerts and notifications

Up next: Diving into Amazon EFS