Q: You're being charged for more CloudWatch API calls than expected. How do you investigate and reduce costs?
1. Cost Explorer — filter by service CloudWatch to see which API calls cost the most (GetMetricStatistics, PutLogEvents, etc.).
#AWS #Monitoring & CloudWatch #L3 #Cloud #Infrastructure #S3
🎙️ Candidate Opening & Architectural Context
""In a previous role, our monitoring paged me for a similar incident across our AWS VPC infrastructure. When addressing this question, I walk the interviewer through our production incident runbook: isolating the blast radius, checking diagnostic logs and metrics, and applying a safe fix.""
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🛠️ Production Runbook & Step-by-Step Resolution
1️⃣
Initial Diagnostics & Root Cause Analysis
- Cost Explorer — filter by service CloudWatch to see which API calls cost the most (GetMetricStatistics, PutLogEvents, etc.).
- Reduce log retention — logs stored indefinitely are the biggest cost driver. Set retention (30/90 days depending on compliance).
- High-resolution metrics — 1-second metrics cost 10x more than 1-minute. Only use for critical alarms.
- Agent config — CloudWatch Agent flush interval. Shorter interval = more API calls. Increase from 10s to 60s for non-critical metrics.
2️⃣
Remediation & Permanent Safeguards
Execute the resolution runbook and verify workload health:
- Reduce custom metric count — each unique metric (unique combination of namespace + dimensions) has a cost.
- Use EMF (Embedded Metric Format) — batch metrics embedded in log entries. Cheaper than individual PutMetricData calls.
- S3 access logs → Athena instead of CloudWatch for high-volume access logs analysis.
💡 The Senior SRE Gold Nugget (Key Architectural Takeaway)
"Pro-Tip: Cost Explorer — filter by service CloudWatch to see which API calls cost the most (GetMetricStatistics, PutLogEvents, etc.).."
⚡ 60-Second Elevator Pitch Talking Points
- Cost Explorer — filter by service CloudWatch to see which API calls cost the most (GetMetricStati...
- Reduce log retention — logs stored indefinitely are the biggest cost driver. Set retention (30/90...
- High-resolution metrics — 1-second metrics cost 10x more than 1-minute. Only use for critical ala...
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