Amazon CloudWatch is a monitoring and observability service that collects performance metrics from AWS resources and applications. For SysOps Administrators, understanding CloudWatch metrics is essential for cost and performance optimization.
CloudWatch automatically collects metrics from over 70 …Amazon CloudWatch is a monitoring and observability service that collects performance metrics from AWS resources and applications. For SysOps Administrators, understanding CloudWatch metrics is essential for cost and performance optimization.
CloudWatch automatically collects metrics from over 70 AWS services including EC2, RDS, Lambda, and ELB. These metrics are organized into namespaces, with each service having its own namespace (e.g., AWS/EC2, AWS/RDS).
Key performance metrics include:
**EC2 Metrics:** CPUUtilization, NetworkIn/Out, DiskReadOps, DiskWriteOps, and StatusCheckFailed. Note that memory and disk space utilization require the CloudWatch agent installation.
**RDS Metrics:** DatabaseConnections, CPUUtilization, FreeStorageSpace, ReadIOPS, WriteIOPS, and ReadLatency/WriteLatency.
**ELB Metrics:** RequestCount, HealthyHostCount, UnHealthyHostCount, Latency, and HTTPCode errors.
Metrics are stored at different resolutions:
- Standard resolution: 1-minute granularity (default for most services)
- High resolution: 1-second granularity (custom metrics)
- Basic monitoring: 5-minute intervals (free tier)
For cost optimization, CloudWatch helps identify underutilized resources through metrics analysis. You can set up alarms to trigger when thresholds are breached, enabling automated responses via Auto Scaling or SNS notifications.
CloudWatch Dashboards provide visualization capabilities, allowing you to create custom views of critical metrics. Metric Math enables calculations across multiple metrics for deeper analysis.
Best practices include:
- Enable detailed monitoring for production workloads
- Install CloudWatch agent for OS-level metrics
- Create composite alarms for complex monitoring scenarios
- Use anomaly detection for dynamic thresholds
- Leverage Contributor Insights for high-cardinality data analysis
Retention periods vary: data points under 60 seconds are retained for 3 hours, 1-minute data for 15 days, 5-minute data for 63 days, and 1-hour data for 455 days.
CloudWatch Performance Metrics
Why CloudWatch Performance Metrics Are Important
CloudWatch performance metrics are fundamental to AWS operations because they provide visibility into the health, performance, and operational status of your AWS resources. For a SysOps Administrator, understanding these metrics is essential for maintaining system reliability, optimizing costs, and ensuring applications meet their performance requirements. Without proper monitoring, issues can go undetected until they impact end users.
What Are CloudWatch Performance Metrics?
CloudWatch metrics are time-ordered data points that represent the behavior of your AWS resources over time. These metrics fall into two categories:
Basic Monitoring - Free tier that collects metrics at 5-minute intervals for most AWS services.
Detailed Monitoring - Paid option that collects metrics at 1-minute intervals, providing more granular visibility.
Key EC2 Performance Metrics: - CPUUtilization: Percentage of allocated EC2 compute units in use - NetworkIn/NetworkOut: Bytes received and sent on all network interfaces - DiskReadOps/DiskWriteOps: Completed read and write operations - StatusCheckFailed: System and instance status check failures
Important Note: Memory utilization and disk space are not default CloudWatch metrics. These require the CloudWatch Agent to be installed on instances.
How CloudWatch Performance Metrics Work
1. Data Collection: AWS services automatically publish metrics to CloudWatch. Custom metrics can be sent using the PutMetricData API.
2. Storage and Retention: - Data points with period less than 60 seconds: Available for 3 hours - 1-minute data points: Available for 15 days - 5-minute data points: Available for 63 days - 1-hour data points: Available for 455 days (15 months)
3. Alarms: You can create alarms that watch metrics and trigger actions based on thresholds. Alarm states include OK, ALARM, and INSUFFICIENT_DATA.
4. Dashboards: Visualize metrics in customizable dashboards for real-time monitoring.
CloudWatch Agent
The unified CloudWatch Agent enables collection of: - Memory utilization - Disk swap utilization - Disk space utilization - Page file utilization - Custom application logs
Exam Tips: Answering Questions on CloudWatch Performance Metrics
Tip 1: Remember that memory and disk space metrics require the CloudWatch Agent. If a question asks how to monitor RAM usage, the answer involves installing the CloudWatch Agent.
Tip 2: Know the difference between basic (5-minute) and detailed (1-minute) monitoring intervals. Questions often test whether you understand when detailed monitoring is necessary.
Tip 3: Understand metric retention periods. Questions may ask about accessing historical data beyond certain timeframes.
Tip 4: For cross-account monitoring scenarios, remember that CloudWatch can aggregate metrics from multiple accounts using cross-account observability.
Tip 5: When questions mention high-resolution metrics, remember these can be collected at 1-second intervals for custom metrics.
Tip 6: Status checks are critical - System Status Checks monitor AWS infrastructure issues, while Instance Status Checks monitor software and network configuration problems on the instance itself.
Tip 7: If asked about reducing monitoring costs while maintaining visibility, consider adjusting metric collection intervals or using metric filters selectively.
Tip 8: For questions about automated responses to metric thresholds, think about CloudWatch Alarms integrated with SNS, Auto Scaling, or EC2 actions like stop, terminate, or reboot.