AWS CloudWatch

Amazon CloudWatch is the default observability hub for many AWS workloads. It stores metrics, collects logs, triggers alarms, and powers dashboards that show how systems behave over time. If DevOps is about reliable delivery and operations, CloudWatch is one of the first services you need because it tells you whether applications are healthy, overloaded, idle, or failing.

Metrics are numeric time-series data such as EC2 CPUUtilization, Lambda errors, request count, or custom business measurements. Logs are raw event streams written by services and applications into log groups and log streams. Alarms watch metrics and notify or automate responses when thresholds are crossed. Dashboards let you combine multiple graphs into one operational view for teams or on-call rotations.

CloudWatch is often confused with CloudTrail, but they answer different questions. CloudWatch asks, “How is the system behaving?” CloudTrail asks, “Who did what in the AWS account?” When an instance has high CPU or a Lambda function times out, CloudWatch is the right tool. When a security group changes or a user deletes a bucket, CloudTrail gives you the API history.

Effective monitoring combines both platform metrics and application signals. CPU and memory alone rarely tell the full story. Queue depth, error rate, request latency, and deployment events help teams spot issues before customers report them. CloudWatch works best when alarms map to meaningful operational thresholds rather than noisy values no one acts on.

Continue with AWS CloudWatch Metrics for hands-on alarms and log patterns.

aws cloudwatch list-metrics --namespace AWS/EC2 --query 'Metrics[0:10].[MetricName]' --output table
aws logs describe-log-groups --output table

Operational note

Good monitoring is less about collecting everything and more about creating signals that lead to action. Prefer alarms tied to user impact, error budgets, queue backlogs, or sustained saturation over noisy one-off spikes. Teams trust observability more when alerts are specific, actionable, and rarely ignored. Shared standards like this make future environments easier to launch, review, and support.