Q: Your application has no observability and you need to build a monitoring stack from scratch on AWS. What would you set up?
Layer by layer:
#AWS #Monitoring & CloudWatch #L3 #Cloud #Infrastructure #EC2
🎙️ Candidate Opening & Architectural Context
""When an interviewer asks how I troubleshoot this in AWS, I frame it through my hands-on production experience. 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
Layer by layer:
- CloudWatch with EC2/ECS/RDS default metrics.
- CloudWatch Agent on EC2 for memory, disk (not in default metrics).
- Custom CloudWatch metrics via AWS SDK (request rate, error rate, business metrics).
- Or: Prometheus + Grafana running on ECS/EKS. More flexible.
- CloudWatch Logs (simple) or OpenSearch (for complex searching).
- Log groups per service, retention policy set.
2️⃣
Remediation & Permanent Safeguards
Infrastructure metrics: Application metrics: Logs: Distributed tracing: Alerting: Dashboards: Uptime monitoring:
- AWS X-Ray — traces requests across services, shows where latency is.
- CloudWatch Alarms → SNS → PagerDuty/Slack.
- CloudWatch dashboards or Grafana for a unified view.
- CloudWatch Synthetics — canary scripts that test your endpoints from outside.
💡 The Senior SRE Gold Nugget (Key Architectural Takeaway)
"Pro-Tip: CloudWatch with EC2/ECS/RDS default metrics.."
⚡ 60-Second Elevator Pitch Talking Points
- CloudWatch with EC2/ECS/RDS default metrics.
- CloudWatch Agent on EC2 for memory, disk (not in default metrics).
- Custom CloudWatch metrics via AWS SDK (request rate, error rate, business metrics).
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