# AWS CloudWatch

> Amazon CloudWatch collects metrics, logs and events from AWS resources and applications, and offers dashboards, alarms and automated actions.

- Source: https://www.itwonderlab.com/aws-cloudwatch/
- Published: 2026-10-05
- Updated: 2026-10-05
- Author: Javier Ruiz Jiménez (https://www.javierruizjimenez.com/)
- Site: IT Wonder Lab (https://www.itwonderlab.com/)

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**Amazon CloudWatch** is the monitoring and observability service of AWS. It collects data from AWS services and from your applications, and lets you visualize it, set alarms and react automatically.

### Key concepts

- **Metrics**: time series such as the CPU of an [EC2](https://www.itwonderlab.com/aws-ec2/) instance or the requests of a [load balancer](https://www.itwonderlab.com/aws-elastic-load-balancing/). AWS services publish metrics automatically (EC2 basic monitoring every 5 minutes, detailed monitoring every 1 minute) and applications can publish **custom metrics**.
- **Alarms**: watch a metric and change state when it crosses a threshold. They can notify [SNS](https://www.itwonderlab.com/aws-sns/) topics, trigger [Auto Scaling](https://www.itwonderlab.com/aws-auto-scaling/) policies or run EC2 actions. **Composite alarms** combine several alarms.
- **Logs**: log groups and streams that store logs from [Lambda](https://www.itwonderlab.com/aws-lambda/), [ECS](https://www.itwonderlab.com/aws-ecs/), [EKS](https://www.itwonderlab.com/aws-eks/), [VPC Flow Logs](https://www.itwonderlab.com/aws-vpc/), [CloudTrail](https://www.itwonderlab.com/aws-cloudtrail/) and the **CloudWatch agent** on servers. **Logs Insights** queries them, and **metric filters** turn log lines into metrics.
- **Dashboards**: graphs of metrics, logs and alarms, also across accounts and Regions.
- **Events**: Amazon EventBridge (the evolution of CloudWatch Events) routes events from AWS services, schedules and SaaS partners to targets such as Lambda.
- **Application and infrastructure monitoring**: Container Insights, Lambda Insights, Application Signals, Synthetics canaries and RUM.

### Pricing

Pay per custom metric, alarm, dashboard, GB of logs ingested and stored, and queries. Many AWS service metrics are free. See the [CloudWatch pricing](https://aws.amazon.com/cloudwatch/pricing/).

### With Terraform

The resources are `aws_cloudwatch_metric_alarm`, `aws_cloudwatch_log_group`, `aws_cloudwatch_log_metric_filter`, `aws_cloudwatch_dashboard` and `aws_cloudwatch_event_rule`.

See also: [AWS CloudTrail](https://www.itwonderlab.com/aws-cloudtrail/) records who did what; CloudWatch records how the systems behave.