slo

Synthetics canaries catch user-journey failures before customers tweet — but a 1-minute canary fleet can quietly dominate the CloudWatch bill. Runtime, VPC, alarm wiring to Application Signals SLOs, and a reproducible checklist.

Monitoring is visibility; alerting is interruption. Teams with 40+ CloudWatch alarms and an actionable page rate under 50% are monitoring loudly and alerting poorly — fix ownership, SLO burn, and canaries before adding another metric.

A stack of ALB + EC2 + RDS Multi-AZ + S3 composes to ~99.83% availability—so promising customers 99.9% is a check you cannot cash. This guide does the composition math, converts it to an error budget (99.9% = 43.2 min/month), and shows why AWS service credits never fund your SLA penalties.