---
title: "Operations, cost, performance, and sustainability"
chapter: "10"
---

# Operations, cost, performance, and sustainability

A design is not finished until teams can see, run, and afford it.

## Observability

Collect metrics, logs, traces, and business outcomes. CloudWatch provides
metrics, logs, alarms, dashboards, and synthetics. X-Ray or OpenTelemetry traces
requests across services. CloudTrail answers who changed AWS resources.

Alarm on symptoms users feel and on causes operators can act on. Every critical
alarm needs an owner and a runbook.

## Infrastructure and change

Use CloudFormation, CDK, Terraform, or another governed infrastructure-as-code
tool. Review changes, scan them, deploy through environments, and detect drift.
Use Systems Manager for fleet operations and Parameter Store where appropriate.

## Cost

Tag and account-separate ownership. Use Cost Explorer, Budgets, Cost and Usage
Reports, Savings Plans, Spot capacity, and Compute Optimizer. Track unit cost,
such as cost per order, not only the monthly total.

The biggest wins usually come from architecture: deleting idle resources,
right-sizing, using storage lifecycle policies, scheduling non-production,
choosing efficient data transfer paths, and matching purchase models to demand.

## Performance

Test with realistic load. Select the right compute, database, storage, and
networking. Cache only with a clear freshness and invalidation policy. Use
CloudFront close to global users and asynchronous work when a response need not
wait.

## Sustainability

Use fewer resources for the same outcome: scale with demand, eliminate idle
capacity, use managed services, efficient processors such as Graviton where
compatible, efficient code, sensible data retention, and Regions that meet both
business and sustainability requirements.