What is Amazon CloudWatch?

Overview

Amazon CloudWatch is an AWS service provided that primarily helps the maintainers of the resources to monitor their systems. The idea is that the systems push metrics to CloudWatch. These metrics can then be visualized over a period to help derive actionable items.

Basic monitoring

AWS services send metrics automatically to CloudWatch. This is at a certain predefined rate. Basic Monitoring refers to the fact that metric collection in AWS is automatically enabled, and does not need the user to do any additional steps.

For most applications on AWS cloud, basic monitoring should suffice for your needs.

Metrics

Metrics in CloudWatch are organized into namespaces. Along with each metric there is a timestamp associated. Different namespace metrics are completely isolated from each other.

AWS services that send data to CloudWatch attach a key/value pair with the metric. This key/value pair can be used for filtering metrics later. These key/value pairs are called as Dimensions

Take a look at the metrics

Collected metrics can be viewed by clicking on the metrics from the CloudWatch service left sidebar.

CloudWatch data hierarchy

Log event

A log event is a record of activity recorded by the resource being monitored. It has a timestamp and a message.

Log stream

Log Streams are groups of log events. All the log events belonging to a single log stream belong to the same resource that is monitored.

Log group

Log groups are collections of log streams. The log streams have the same retention and permissions.

This categorization and grouping of logs help keep the logs organized.

Conclusion

You can set alarms specifying threshold values. These alerts can get pushed to your company's preferred notification service. This ensures that whenever there is an issue, proactive alerting is done.