3.2.1. Amazon CloudWatch for Application Monitoring (Metrics & Logs)
First Principle: Amazon CloudWatch provides a centralized service for collecting and analyzing application metrics and logs, enabling developers to monitor application health, performance, and identify operational issues.
Amazon CloudWatch is the primary monitoring and observability service for AWS. For developers, it's essential for understanding how their applications are performing in real-time.
Key CloudWatch Capabilities:
- Metrics: (Time-series data points that represent a measurement of a particular aspect of a resource or application.) Collects standard metrics from AWS services (e.g., Lambda invocations, DynamoDB read/write capacity). Developers can also publish custom metrics from their applications (e.g., successful transactions, API call latency).
- Logs: (Centralizes logs from various sources, such as Lambda functions, EC2 instances, and custom applications.) Allows for real-time monitoring and searching. Developers use CloudWatch Logs Insights for ad-hoc querying.
- Alarms: (Monitors metrics and automatically triggers actions when a defined threshold is breached.) Notifies developers of critical issues (e.g., high error rates).
- Dashboards: Create customizable visualizations of metrics and alarms for operational oversight.
Scenario: Your application, deployed on AWS Lambda and using DynamoDB, starts experiencing increased latency. You need to quickly identify if the issue is with the Lambda function itself, the DynamoDB table, or an integration point.
Reflection Question: How does Amazon CloudWatch, by providing both standard metrics (e.g., Lambda invocation duration, DynamoDB throttled requests) and centralized logs (e.g., Lambda function logs), enable you to monitor application health and pinpoint operational issues?