Building Unified Monitoring with Amazon CloudWatch - Designing Metrics, Logs, and Alarms
Build unified monitoring with the three pillars of metrics, logs, and alarms. This article covers interactive analysis with Logs Insights, high-precision notifications with composite alarms, and leveraging Embedded Metric Format.
Overview of CloudWatch
CloudWatch is a service that provides monitoring, log management, and alarms for AWS resources and applications. It delivers unified monitoring through three pillars: metrics (numerical data), logs (text data), and alarms (threshold notifications). You can collect application-specific indicators with custom metrics and perform interactive log analysis with Logs Insights.
Metrics and Alarm Design
AWS services automatically send basic metrics such as CPU utilization, network I/O, and request counts to CloudWatch. Custom metrics are sent via the PutMetricData API to monitor business metrics (orders per minute, revenue per hour). Alarms trigger SNS notifications or Lambda executions when a single metric exceeds a threshold. Composite alarms combine multiple alarms with AND/OR logic, reducing false alerts by triggering only when conditions like "CPU utilization is high AND memory utilization is high" are both met. Logs Insights is a SQL-like query engine for CloudWatch Logs that lets you instantly aggregate error logs and analyze latency.
Logs Insights and Contributor Insights
CloudWatch Logs Insights is an interactive log analysis query engine that uses its own query language to search and aggregate log data. By combining commands such as fields, filter, stats, and sort, you can aggregate error logs, analyze latency distributions, and search for specific patterns. Query results can be pinned to dashboards for regular monitoring. Contributor Insights is a rule-based analysis feature that automatically identifies the top N contributors from log data, such as the API with the most errors or the IP address with the most requests. Lambda Insights automatically collects performance metrics for serverless functions, including cold starts, memory utilization, and execution time. To deepen your operational monitoring expertise, specialized books on Amazon are a useful resource.
CloudWatch Cost Optimization
The main cost drivers for CloudWatch are custom metrics ($0.30/metric per month), log ingestion (approximately $0.50 per GB), and log storage (approximately $0.03 per GB per month). Differentiate between standard resolution (60 seconds) and high resolution (1 second) for metrics, and limit high resolution to only the metrics that require it. Set retention periods per log group, such as 7 days for debug logs and 1 year for audit logs, to reduce storage costs. Use Embedded Metric Format (EMF) to automatically extract metrics from application logs, reducing PutMetricData API calls for custom metrics. Regularly review and clean up unnecessary metric filters and alarms.
Summary
CloudWatch is a service that provides unified monitoring through metrics, logs, and alarms. Perform interactive log analysis with Logs Insights, and achieve high-precision notifications by combining multiple conditions with composite alarms. Automatically extract metrics from application logs with Embedded Metric Format, and identify top N contributors with Contributor Insights.